BaseLayers

Layer categories are separated into base layers (next to the skin), mid layers (added atop the base layers to add warmth without adding bulk), insulating layers of fleece, wool or down worn in cold conditions under the shell, and the outerwear (hard shell or soft shell, either water resistant or waterproof). These layers are available in several weights, and often midweight base layers are used as mid layers, and heavy base layers can be used as insulating layers as an alternative to a sweater, vest or insulating jacket. There is no specific dividing line regarding the use of various layer weights, but there are purpose-designed insulating layers, such as lofted jackets (synthetic, wool, fleece or down), sweaters and insulating shirts.

This page details current lightweight, midweight and expedition weight
synthetic and Merino base layers, and gives examples of their usage.

By the time you finish this page, you will likely know more than you wanted to about base layers, but you will also know exactly what to think about and how to select base layers which will be the best for your particular needs.

The temperature ranges indicated on this page are based on light to medium activity. Strenuous activity will allow you to be comfortable at lower temperatures and will bring the upper temperature range down, lack of activity will have the opposite effect. Also, people who are permanently acclimated to lower temperatures will find the entire range lowered in their estimation.

Use the Layering Index links below to jump to a section.

 

Layering Index
 

 

Introduction

Base Layers: Synthetic and Merino

Field Shirts, Pants, and Outerwear

Legacy Synthetics

Summary and Recommendations

Product Descriptions

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Minaret_Ritter_Sunrise_2209-10_SXL


Minaret Ritter Sunrise 2209-10 SXL

The Minarets, Mount Ritter and Banner Peak in the Ritter Range of the Sierra Nevadas.

(from the Assorted Scenic section, Potpourri page)

There is a rule of thumb that has been around for quite a while which states that you should use a three layer system consisting of a base layer, an insulating layer, and a shell. This method gives you no options for temperature regulation. If you wear layers which are heavy enough to keep you reasonably warm when you start out, before you begin generating body heat, you are going to be too warm when you are generating body heat and far too hot as the temperature rises later in the day. When you strip off the insulating layer, you will lose quite a bit of body warmth all at once, and may become chilled. If there is more than a 30 degree swing in temperature during the day, or you alternate between strenuous activity to low activity levels or rest, it is quite likely that you are going to spend the day fluctuating from too hot to too cold. It is better to use a larger number of lighter layers which allow you to fine tune your body temperature, using materials with superior temperature regulation characteristics.

As was mentioned on the section index page, the last time I acquired a new kit I did it in stages, first planning on augmenting my existing legacy kit and then deciding to create multiple interacting kits made from three complete layering arrays designed for different conditions. The original acquisition was two pair of Merino briefs and a Smartwool Funnel Zip midweight Merino layer intended to act as an interstitial layer between two upper legacy synthetic layers to widen the range of temperatures within which the layering array could operate and improve the temperature regulation. The Funnel Zip did exactly what it was expected to, and the Merino briefs were a revelation, prompting me to consider both acquiring a set of current synthetics and exploring the options for Merino layering arrays as well as the possibilities generated by creating interacting arrays of synthetic and Merino.

The result was a greatly increased flexibility over a wider range of temperatures with significantly less bulk.

Below are the layering arrays which resulted from these experiments
and a detailed breakdown of the individual products and field testing.
—  Only base layers and insulating layers are listed in the arrays  —

Layering Arrays

Tops


Array 1
Breathable Synthetic with Interstitial Merino element and Merino Insulating Layer
 

Patagonia Capilene 1 -or- WoolX X302 T-shirt
Patagonia Capilene 2 Lightweight Zip-Neck
Patagonia Merino 3 Midweight Zip-Neck

Patagonia Capilene 3 Midweight Zip-Neck
Patagonia Capilene 4 Thermal Weight Hoody
WoolX X704 Blizzard Expedition Weight Zip-Neck


Array 2
Breathable Merino with Interstitial Synthetic element and Merino Insulating Layer
 

Icebreaker GT200 Sprint Crew -or-
Mountain Hardwear Integral Pro Crew
Patagonia Merino 2 Lightweight Zip-Neck

Patagonia Merino 3 Midweight Zip-Neck
Patagonia Capilene 4 Thermal Weight Hoody
Smartwool MerinoMax Heavy-Midweight Zip-neck


Array 3

Minimal Merino Array
 

WoolX X302 S/S or X304 L/S T-shirt
WoolX X507 Midweight Zip-Neck

Patagonia Merino 3 Midweight Hoody
WoolX X704 Blizzard Expedition Weight Zip-Neck


Used with a light shell, Arrays 1 and 2 are good to below freezing, Array 3 to the mid-30s
(assuming light to medium activity — strenuous activity allows use to lower temperatures).
Listed below are numerous alternate tops which have a group of desirable characteristics.
These tops can also be used together in extended arrays for use at very low temperatures.
(See the Summary and Recommendations page for suggested extended layering arrays).

Bottoms
 

Smartwool NTS 195 Lightweight Boxer Brief
-or- WoolX X303 Lightweight Boxer Brief -or-
Patagonia Merino 1 Silkweight Boxer Brief

WoolX X509 X-Plorer Midweight Bottoms
Patagonia Capilene 2 Lightweight Bottoms
Patagonia Merino 2 Lightweight Bottoms


The Bottoms can be used alone (with a brief) or together in an extended array at lower temperatures.

Keep in mind that how you handle heat and cold is dependent upon your body type, percentage of body fat, circulation, and other factors. I am 5'6" and 150 pounds (168 cm, 68 kg), and am an ex-gymnast (to give you an idea as to my body type). Except for a little around the middle (you know how it is), I do not have much built-in insulation, and I generally require more layers to be comfortable in cold weather than some people. I am also acclimated to a warmer climate (Southern CA), and until I have spent some time in the mountains or other colder areas, I require more layers than people who are already acclimated to colder temperatures. Evaluate your tolerance to cold weather and your typical activity levels, and plan your kit accordingly.


Patagonia Capilene Synthetic Base Layers

The Patagonia Capilene line of synthetics has evolved over many years. The line as a whole is lightweight and designed in a manner which allows them to be used over a very wide range of temperatures. The individual elements of the line are designed to work in synergy with each other, and while several of the garments can be used alone, the moisture transport and temperature regulation characteristics are superior when used along with another layer. The Capilene products use the Polygiene textile treatment, a Bluesign approved antimicrobial odor control technology which uses silver chloride made from 100% recycled silver on the fabric surface to combat the dreaded synthetic stench.

The current Patagonia synthetics seem from my testing to be noticeably better at temperature regulation than legacy synthetics. The legacy synthetics as a group seemed to have a 10 to 15 degree window of comfort between a little cool and a little warm, and about 15 to 20 degrees between stripping off or putting on a layer... some at the lower end of that scale, and some at the higher end. The current synthetics are a little different. The Capilene 1 T-shirt and Capilene 4 have a much wider usable range. The Capilene 2 and Capilene 3 have a little wider range of usable temperatures, and their synergy allows them to be used together over a much wider range than either can be used alone. The group with the Capilene 4 is far superior at temperature regulation than the group without the Capilene 4, but the temperature regulation characteristics of the synthetics as a group still do not approach the wide usable range of Merino wool, although they wick moisture more efficiently.

In my opinion the most effective way to work with synthetics is to insert a Merino layer
in between two synthetic layers, allowing you to get the advantages of both materials.

Capilene 1 Silkweight Graphic T

The Patagonia Capilene 1 Silkweight Graphic T is a 156 g/m, 94% polyester 6% Spandex Jersey blend which allows air to flow through the weave, and when worn with another layer this shirt wicks moisture and adds warmth. Quick-drying, with offset shoulder seams to avoid pack straps and side seams which roll forward for comfort under outer layers, it is amazingly comfortable in hot weather with even the slightest breeze, and when under a field shirt it wicks like a champion and can be worn to very high temperatures. It is still quite comfortable at over 90 degrees in direct sunlight under a field shirt. The Capilene 1 shirt has a superb feel next to the skin, and works synergistically with its colleagues, improving the performance of the other Capilene tops in the areas of moisture transfer, thermal efficiency, and temperature regulation.

The attention to detail in the Patagonia design can be seen in the seam placement forward of the shoulders and sides to avoid chafing by the pack, and the extra piece of thicker black material below the inside of the rear neck seam, allowing you to easily determine the correct orientation of the T-shirt in any light... a nice touch.

One of the questions I have been getting since this dissertation went up is: “Why a T-shirt instead of a long-sleeved Crew and which T-shirt do you like best?” A long-sleeved crew is useful as a core base layer in lower temperatures, but less flexible as the temperature rises. I prefer to use a short-sleeved T-shirt when the day will peak over 75 F., which allows me to bare my arms as the temperature rises (covering them with a vented field shirt whose sleeves can easily be rolled up and fixed in place), and using a lightweight and/or midweight zip-neck atop the T-shirt when required, which allows me to zip down the front to vent heat as needed. Of course, in very cold weather or in buggy conditions the long-sleeved T is the best option (I have several).

Regarding which I like best, it depends on the temperature range. If it is going to be quite hot at mid-day (between 90-100+), there is no doubt I will select the Capilene 1. While it does not regulate temperature as well as either Merino T-shirt, it wicks moisture better than either (often, after a sweaty session, I take off my field shirt and the Capilene 1 T-shirt is dry). You may feel warmer in the Capilene than the Merino 1 up to about 95 (where the Merino starts to become too warm and tends to saturate more easily), but you will feel drier and above 95 there is no question it is the right shirt. The Merino 1 T-shirt does wick quite well, just not as well as the Capilene. Both Merino T-shirts are far better at keeping you warm in cool weather and cool in warm weather... the WoolX X302 at the lower end of the temperature scale and the Merino 1 at the higher end. They are both good in mild temperatures, and the Merino 1 is more breathable. If it is going to start out cold, I use the WoolX. If the day is starting in the 50-60 degree range I select the Merino 1. They all have their place. Select the one(s) that make most sense for you.

Capilene 2 Lightweight Zip-Neck

The Patagonia Capilene 2 Lightweight Zip-Neck is a 122 g/m Polartec Power Dry (100% polyester) double-knit lightweight mock zip-neck with a 13” extra-long welted zipper (with zipper garage) to keep metal away from skin, offset shoulder seams to avoid pack straps, side seams which roll forward for comfort under outer layers, and long sleeves with thumb loops. The open knit interior surface increases wicking effectiveness, and the smooth outer surface slides under upper layers. The zipper welt has a nice texture which feels good against the neck, although it is not quite as luxurious as the Capilene 3 welt. It can be used as a core layer, but it really works better with the Capilene 1 shirt under it (which also feels better against the skin). Together, the Capilene 1 and 2 can be used from the 50s to about 80-85 degrees, depending upon your cold weather acclimation and the level of activity. If you are a polar bear, you could probably use them into the 40s.

Capilene 3 Midweight Zip-Neck

The Patagonia Capilene 3 Midweight Zip-Neck is a 183 g/m Polartec Power Dry (100% polyester) double-knit midweight high zip-neck top with an 11” long welted zipper (with a zipper garage, like all Patagonia zip-necks), offset shoulder seams to avoid pack straps, side seams which roll forward for comfort under outer layers, and long sleeves with thumb loops. The interior surface is a staggered interlocking grid which is brushed for warmth and softness, and the smooth outer surface slides under outer layers. The interior of the Capilene 3 has been vastly improved over the legacy top, and it can be worn against the skin although it works better in all respects if you are wearing the Capilene 1 shirt below it. The interior of the zipper welt is a velvety smooth fabric which feels like microfiber. The neck of the top reaches to the top of your neck. I smiled when I wrote that.

The Capilene 1, 2 and 3 were obviously designed to work well as a team. Together they are a wicking force of nature... moisture is transported away from the body with speed and efficiency. Together they are quite warm... depending upon your cold weather acclimation and the level of activity they work from the high 40s to about 75-80 degrees. Together the temperature regulation characteristics are good... you can wear the group comfortably to a higher temperature than you can wear the Capilene 3 alone (as is the usual case, temperature regulation and wicking characteristics of the Capilene 2 and 3 tops improves when you wear the Capilene 1 T-shirt). The arm diameter of the Capilene 3 top is a little larger than the Capilene 2, which leaves room below for the other top. The neck height of the Capilene 2 is lower than the Capilene 3, and the zipper of the Capilene 2 is 2” longer than that of the Capilene 3, so when they are both pulled down (or up) the zippers do not fall atop one another.

With all of this said, the Capilene 1, 2, 3 array is best in the cool to hot temperature ranges, although during strenuous exercise they could be used at lower temperatures. At low to medium activity levels near the lower end of the range I add the Capilene 4 hoody. Inserting a Merino top in between the Capilene 2 and 3 widens the effective temperature range. The Capilene 3 zip-neck also makes a superb top layer for use over a Merino 1, 2, 3 array in cool-to-warm weather (my primary use for this top).

Capilene 4 Thermal Weight 1/4-Zip Hoody

The Patagonia Capilene 4 Thermal Weight Hoody is made with an ultralight 129 g/m Polartec Power Dry double-knit fabric (92% polyester, 8% Spandex) that has a grid-patterned brushed fleece interior with wide gaps between the tiny fleece grids. It is a highly breathable and surprisingly warm base layer or light insulating layer with a double-layer hood that traps heat, a smooth face which glides under outer layers, extra-long sleeves with thumb loops, a zippered chest pocket, a long welted center-front zipper which reaches well below the chest, and a drop-tail hem. The collar is quite high, reaching above the upper lip when the hood is closed, and the double-layer hood is anatomically shaped. With the hood down and the neck zipped up and folded over, it makes an exceptionally effective neck gaiter which can be pulled up over the chin if the wind is chilly (although you will probably put the hood up in that case). When the hood is zipped up and over the lip, the top of the zipper welt in the lighter two colors forms a mustache. Someone had a sense of humor. The top packs into a LowePro 1W belt bag (5” cylinder, 6” tall).

This hoody is unusual in many ways. It is extremely lightweight, yet very warm. The large gaps between the fleece blocks in the grid allow the material to breathe very well (and let in any trace of breeze). It can be used in mild to warm weather with a T-shirt (or alone), and it works synergistically with layers worn below. I have used it alone in 80 degree weather in direct sunlight with a light breeze, and while I was sweating a bit, it was still comfortable as the fabric let in quite a lot of the breeze. I have the chartreuse version (aka the Deck the Halls version because it can be seen from space), and besides the high visibility of this color (it reflects enough sunlight to blind birds and pilots of low-flying aircraft), reflecting sunlight helps to keep you cool. As has usually been the case, in combination with the T-shirt it wicks and regulates temperature better and is more comfortable. The upper limit of the T-shirt and Capilene 4 Hoody is at about 90 degrees. Normally, I would remove this top before reaching those temperatures, but I had to test it.

At lower temperatures, when used along with an underlying layer array, the Capilene 4 hoody adds breathable warmth. When covered with a layer which traps air, it gets even warmer... the Capilene 1 through 4 along with the Torrentshell Pullover makes an extremely flexible array. When using the Capilene 4 Hoody in cooler temperatures, it is best to use another layer on top to block the wind. I use a field shirt, the Nike Hyperwarm 1/4-zip, or the Smartwool MerinoMax on top in cold to cool temperatures, either with or without a shell, depending on circumstances. In warmer weather or during strenuous activity, the air flow helps with temperature regulation and it is used as the top layer.

The way that the interior grid is constructed, with small fleece-blocks alternating with equal-sized gaps, creates a lofted series of miniature ripples which alternately heats and breathes. This is a highly technical fabric which works very differently depending on whether it is worn next to the skin or over other layers. When worn as an insulating layer over other layers with another layer or a shell on top it is exceedingly warm. The sleeves are long enough that you can extend your arm over and behind your head with your thumbs in the thumb loops without putting pressure on the web between thumb and forefinger (great for climbing). The extreme flexibility of this hoody as an insulating layer and as a base layer makes it one of the most versatile tops I have used.

Capilene 2 Lightweight Bottoms

The Patagonia Capilene 2 Lightweight Bottoms are made of 122 g/m Polartec Power Dry 100% polyester double-knit fabric. These have an open knit interior surface to increase wicking effectiveness, a smooth outer surface to slide easily under outer layers, a functional fly, a gusseted crotch for added mobility, and a brushed elastic waistband for comfort next to skin. The material wicks and breathes well and dries exceptionally quickly. Unlike the legacy Capilene 1 bottoms the current Capilene 2 has longer legs with longer cuffs and does not slip up the leg when squatting or raising the leg high.

The Capilene 2 bottom is used alone in chilly to mild conditions or with one of the Merino bottoms in colder conditions. In very cold conditions, it will be used between the WoolX X509 Merino and the Patagonia Merino 2 bottoms in an array.

Capilene 1 Silkweight Boxer Briefs

The Patagonia Capilene 1 boxer briefs are a 156 g/m, 94% polyester 6% Spandex Jersey blend which allows air to flow through the weave, and the tagless brushed elastic waistband is comfortable next to the skin. The Polygiene odor treatment combats microbial growth. The underwear are loose where it counts, tight elsewhere, and the leg reaches to the middle thigh, longer than their Merino briefs (which tend to ride up). The Patagonia briefs are more breathable than the Ex Officio briefs, and are the finest of the various synthetic briefs I have used over the years, but they are still best used in mild to cold weather as they are seem to breathe less well than Merino underwear. They are great for medium activity into the 70s or strenuous activity into the 60s, but if you go much above those temperatures they seem to become a little overwhelmed, creating a rather humid environment down there. These are the best synthetic underwear I have ever used, and I have tried quite a number of them, but in higher temperatures they create a humid environment unless you are wearing vented shorts or pants such as the Kuhl Krux or the Kuhl Kontra Air with all of the vented pockets open.
 

As an aside regarding partial arrays, the Capilene 1 T-shirt and Capilene 4 Hoody are extremely useful for mild to warm weather (add a Capilene zip-neck if there is a chilly wind or the temperature drops). The Capilene 1 and 4 combination is useful up to fairly high temperatures even in direct sunlight (assuming you have the chartreuse version which reflects sunlight)... as long as there is a breeze, because the Hoody will let in any trace of breeze to keep you cool.

On the other end of the temperature spectrum, the addition of either a lightweight or midweight Merino layer between the Capilene 2 and Capilene 3 tops extends the low end of the temperature range down significantly as well as widening the effective temperature range by increasing temperature regulation effectiveness (allowing use to a higher temperature).

With regards to the Polygiene antimicrobial treatment, several hours of sweaty use still builds up an odor, but far less than the stench I am unfortunately used to with legacy synthetics. A quick rinse and dry, and the odor is reduced to barely detectable. After another sweaty session, the odor accumulates and again the garment is rinsed and dried. Each time this is done the odor is a little more noticeable. You can continue this process for three to five days before odor becomes objectionable, depending upon your odor tolerance (and that of your companions). This is light years better than the legacy synthetics. It is nothing like Merino, which can be worn five solid days in the upper temperature range without a rinse before the stink alarm goes off... but it is a vast improvement which should significantly reduce the need to carry replacements.

Nike Pro Hyperwarm Special Field Fitted 1/4-zip Mock Neck

This Special Field version of the Pro Hyperwarm fitted 1/4-zip mock-neck (~220 g/m, body: 88% polyester, 12% spandex, mesh panels: 92% polyester, 8% spandex) was acquired as an exterior layer for use atop or within both Capilene and Merino arrays, to act as a windshirt and to provide a more durable surface. The exterior surface of the body is a dense, smooth knit, and is essentially a softshell with mesh panels on the back and under the arms for increased ventilation. The bottom hem is extra long, reaching the upper thigh, and there are ergonomically designed flat-lock seams throughout. The interior of the Dri-Fit fabric has a brushed surface, and wicks moisture through to the exterior surface of the fabric quite effectively. It has extra-long sleeves (with thumbholes) like the standard Nike Pro Hyperwarm Fitted 1/4-zip mock but without the heat-transfer markings on the back mesh and the Nike Pro on the nape of the neck, and with an embroidered swoosh logo on the left breast instead of on the left side of the neck.  It was available in multiple field colors plus black, white and obsidian, and the only place that I am aware of where it was available was at tacticalgear.com (it may have been a custom order by the retailer).

While the fabric weight of the Hyperwarm is about the same as the Merino 3 (thus the ~220 g/m estimate), it is a fairly dense and smooth surface, much like a softshell jacket, and regarding warmth, it acts more like a 300 g/m garment. It traps air and blocks wind effectively, while still breathing well enough for comfort, and wicks quite well. It is not at all waterproof, though. The Nike Hyperwarm is a superb windshirt and an effective light insulating layer, but it soaks instantly in a rainstorm. I am going to try applying a DWR coating to it to attempt to reduce this issue.

When used atop a Merino array, the Hyperwarm 1/4-zip provides additional hand protection and wind resistance as well as a more durable, abrasion-resistant surface which is especially useful when bushwhacking or moving through dense forest. When actually climbing on rock I generally replace this with the legacy Nike Dri-Fit 1/4-zip as it is already abraded. When it is used atop the full Patagonia Capilene array it extends the temperature range of the array down into the 30s (see the Summary page).

The Nike Hyperwarm and the Patagonia Capilene 4 Hoody go really well together... while they are only about 450 g/m together, they act more like 575-600 g/m due to the insulating properties of the Polartec grid fleece when covered by a layer which traps air and blocks wind, combined with the additional insulating properties of the Nike Hyperwarm fabric.

Capilene_1-4_InteriorComp


Capilene 1,2,3,4 Interior Surface Images

The interior surfaces of the Capilene 1, 2, 3 and 4 synthetics. Capilene 1 is a 156 g/m jersey knit blend of polyester/spandex. Capilene 2 is a 122 g/m Polartec Power Dry polyester double-knit with an open-knit surface to increase wicking effectiveness. Capilene 3 is a 183 g/m Polartec Power Dry polyester double-knit with a brushed interlocking grid interior for more warmth. Capilene 4 is an ultralight 129 g/m Polartec Power Dry polyester/spandex double-knit with a grid-patterned brushed fleece interior that has wide gaps between the tiny fleece grids which allow the material to breathe as well as provide warmth.

Capilene_1-4_ExteriorComp


Capilene 1,2,3,4 Exterior Surface Images

The exterior surfaces of the Capilene synthetics are smooth to allow them to slide easily under outer layers.
Note the welted zippers in the Capilene 2, 3 and 4 images, and the flat-lock seam in the Capilene 1 image.

Capilene_3_SurfaceComp


Current and Legacy Capilene 3 Interior Surface Images

A comparison of the current and legacy Capilene 3 interior surfaces. The current Capilene 3 is a brushed
interlocking grid which is much softer against the skin than the earlier version, which was rather irritating.

Capilene_4_Interior-Exterior


Capilene 4 Exterior and Interior Surface Images

Detail of the smooth exterior face and the spaced fleece grid interior of the highly breathable Capilene 4.

Merino Wool

As a general rule fewer layers of similar weight are required for a given temperature range with Merino wool than with synthetics. Merino wool also has a much wider range of effective temperature use than the typical synthetic (there are some exceptions depending on how the synthetic is used in an array, such as the Capilene 4). Merino wool also typically reaches its upper limit at a lower temperature than synthetic layers (depending on the fabric weight). In general, I prefer Merino to synthetic base layers, with a few exceptions depending on conditions.

Unlike polyester, Merino can move moisture in its vapor state as well as mechanically in the liquid state as polyester does. Wool fibers have a natural crimp which create dead air space, which is a superb insulator. Wool fibers can move moisture even when saturated and can absorb up to 30% of their dry weight before feeling wet (most synthetics feel wet after absorbing about 7% of their dry weight). Merino wool stores moisture in the core of the fiber and as your body heats up, the stored moisture begins to evaporate, cooling the air between your skin and the fabric. Merino naturally resists odor, and the small fiber size eliminates the itch of traditional wool, increases the elasticity of the fabric, and reduces drying time.

Wash Merino wool in cold water (inside-out or in a lingerie net), dry on low heat to nearly dry (or air-dry).

Merino wool has become increasingly popular over the last 10 years or so for its next-to-skin comfort, as well as its wicking ability and thermal regulation effectiveness. Merino is most effective at temperature regulation when worn next to the skin. Merino has replaced traditional wool due to its superfine fibers which are typically about 18 microns, roughly 2/3 to 1/5 the diameter of the human hair (which ranges from 30 to 100 microns). These finer fibers and smaller scales make Merino one of the softest types of wool available, and Merino is also capable of retaining warmth when wet, thus helping the user to avoid hypothermia. It also has an excellent warmth to weight ratio compared to other wools.

As with the synthetic products, there are no standards regarding what fabric weight constitutes lightweight or midweight, etc. Different manufacturers label their products relative to the rest of their range, within generalized categories. Sometimes a product is labeled midweight when it is similar in weight to another manufacturer’s lightweight. It can be confusing, thus I am giving fabric weights per unit area wherever possible.

Patagonia, Smartwool and WoolX make their products in different weight ranges, and some weight ranges nearly overlap:

Patagonia tops are (in grams of wool per meter square):

Silkweight (120 g/m), Lightweight (165 g/m) and Midweight (220 g/m);

Smartwool tops are:

Micro (150 g/m), Light (195 g/m), Mid (250 g/m), and heavy-midweight (280 g/m);

WoolX tops are:

Lightweight (170 g/m), Explorer (midweight, 260 g/m), and Blizzard (expedition weight, 400 g/m).

The bottoms are typically of similar weights, although the Patagonia Lightweight Bottoms are of a different blend at 215 g/m. As you can see, the Patagonia Silkweight is considerably lighter than the Smartwool Micro, their Lightweight is just a bit heavier than the Smartwool Micro and about the same as the WoolX Lightweight, and the Patagonia Midweight is lighter than the other two manufacturer’s Midweights, which are about the same weight. The Smartwool Light fits between the Patagonia Lightweight and Midweight, and the WoolX Blizzard 400g/m top is nearly double the weight of the Patagonia Midweight.

The Patagonia line of Merino, when used in a single layer of each weight, will take you from cool temperatures to very hot as you take off each layer. The Smartwool line used in the same manner will take you from chilly to hot, and the WoolX line will take you from cold to very warm. These temperature designations are purposely vague, as they depend on both the activity level and the individual’s acclimation to cold weather. Of course you can mix weights from different manufacturers or wear more than one of each to alter these line characteristics, but I think you can see that each line is targeted at a different heat range.

Patagonia was crafty in the design of their Merino/Capilene blend. From the tests I have done, 100% Merino is superior to the Merino/Capilene blend in temperature regulation: a lighter weight garment made of Merino/Capilene feels warmer when worn in a temperature near the upper limit than a heavier weight 100% Merino garment worn in the exact same conditions... but, if there is a breeze, the fact that Patagonia made their garments quite breathable means that it will feel cooler, as their products are all more breathable than the 100% Merino products with which I have experience. Also, since their products are lighter in weight, they are often worn in an array in conditions where you are either using a lesser number of 100% Merino garments, or wearing a single garment. The multi-garment array will work together synergistically to achieve superior temperature regulation. Crafty.

Many Merino products are in dark colors or black, which is great for gathering energy from the sun when it is cold, however as the temperature rises, you want to put on a light colored field shirt to reflect the sun to allow you to withstand higher temperatures (some lightweight Merino products are available in lighter colors for this reason, such as T-shirts and crew tops).

As you saw in the product list, I selected T-shirts from WoolX and Patagonia in their lightest weight range. WoolX does not yet make a Lightweight Crew or Hoodie (coming in June), but Patagonia does make a Silkweight (and Lightweight) Crew. A T-shirt allows me to expose my arms when stripping to the core layer, and I cover my arms with a field shirt (or roll the shirt sleeves up and fix them in position). Other than when wearing a T-shirt in the core layer position, I have determined that it is best for me to work with a zip-top to allow me to zip down to release heat or zip up to conserve heat. Plenty of people do like to use Crew tops.

I will first discuss a few assorted Merino tops (midweight and heavy-midweight tops from Smartwool and light midweights from Icebreaker and Uniqlo) and the Smartwool Boxer Briefs.

Smartwool NTS Mid 250 Funnel Zip T

The Smartwool NTS 250 Funnel Zip T is a non-gusseted raglan-sleeved 250 g/m 100% Merino zip-top with a long 15.5" welted zipper which can be opened to vent body heat and a high-back neck for coverage to the hair line. The Smartwool Funnel Zip was acquired one size up to allow it to be used between two synthetic layers to act as a shallow lofted layer, improving temperature regulation when wearing a legacy synthetic array. It can also act as a light insulating layer when used atop another Merino midweight. This is an exceptionally good way to improve the performance of a legacy synthetic array, and as it is as warm as two typical synthetic layers it gives you the opportunity to either extend the temperature range of your kit, remove two synthetics to get the same warmth with better temperature regulation, or to delegate two synthetics to spare change status.

Unlike cotton tops or vented field shirts, Merino tops work most effectively when they are tight rather than loosely fit. They also wick and regulate temperature more effectively when used in combination with another layer. My concept for getting this top one size large was to allow it to be used over two synthetics and under a third, or over a midweight Merino layer, and when worn in that manner it is a tighter fit. The Funnel Zip is often used over a light-to-medium array when I start out at the lower end of the temperature range to add insulation before I generate body heat, and gets put back on when the activity level drops. The front of the neck of the Funnel Zip is roughly the same height as a mock neck, but the rear of the neck is quite high. When worn over the WoolX X507, the back of the Funnel Zip neck goes over the top of the WoolX neck, but the front is about an inch below the top of the WoolX neck, thus the zippers do not overlap when both are zipped up.

Besides its original intended use as an interstitial layer between two synthetics, the Funnel Zip is most often used atop another midweight Merino layer (either the Patagonia Merino 3 zip-neck or the WoolX X507 zip-neck, along with a Merino T-shirt) to create a highly flexible cool-to-warm weather 3-layer array.

When compared to the WoolX midweight (260 g/m), the Smartwool Funnel Zip allows more air through the weave. You can feel a breeze more through the Funnel Zip. When comparing temperature regulation characteristics of the Smartwool vs. the WoolX midweight, both used over the WoolX T-shirt, the WoolX regulated temperature better (It was warmer in cooler weather and cooler in warmer weather), but considering that the WoolX is tighter, it is possible that the difference was caused by the additional air space under the Smartwool. What I can say is that the Smartwool functions perfectly as intended when used over two synthetic layers and under a third (or over a midweight Merino top), as I can wear that array to a higher temperature with the Smartwool than without it, and of course it is significantly warmer in cooler temperatures than when I wear the three synthetics with another synthetic of roughly the same weight as the Smartwool in its position.

While it is not as effective at wicking or regulating temperature when worn alone due to the looser fit, this is a very comfortable top which is often worn alone or under a field shirt in milder temperatures. When worn under a field shirt, the ability to open the extra-long zipper to well below the bottom of the chest allows you to vent body heat quite effectively. The Smartwool NTS 250 Funnel Zip does not have as good a surface finish as the WoolX X507 X-Plorer (260 g/m), as can be seen in the surface comparison image below, and it pilled a bit after its first wash (wash inside-out or use a lingerie net).

Smartwool MerinoMax Heavy-Midweight Half-Zip

A relaxed fit, densely woven 280 g/m Ponte knit top (97% Merino, 3% Elastane) with extra-long sleeves and low-profile in-seam thumbholes above the wide cuffs that disappear when not in use. The zippered chest pocket has a grommeted hole in the polyester mesh pocket interior lining allowing a headphone cord to pass through to the inside of the top (the pocket is on the left side so it does not stack on top of the Funnel Zip pocket, which is on the right side). It has a long 13" zipper with storm welt, a high neck that is loose enough to allow two high-neck tops below, and the wide cuffs of the extra-long sleeves protect the back of the hands (especially when using the thumbholes). All seams are flatlock stitched to eliminate chafing if worn next to the skin.

The Smartwool MerinoMax half-zip is a legacy top (also available in a full-zip), both of which are still available at a discount from a number of distributors (the more recent equivalent is the PhD Hyfi mid-layer, the primary differences are a more athletic fit and zippered hand pockets, also still available at a discount. Neither are in the current line). The MerinoMax is a loosely fit top making it a superb choice for a upper layer, especially when used along with the Patagonia Capilene 4 hoody as the looser fit traps air assisting the insulating character of the lofted Polartec fleece hoody. It is also often used atop the Smartwool Funnel Zip to extend the temperature range of another array.

The Smartwool MerinoMax was acquired one size up, and along with the relaxed fit this allows it to be used atop a full array to extend the temperature range of the array, or atop the Patagonia Capilene 4 hoody, where the looser fit traps more air under the densely woven wool improving the insulating properties of the pair.

Smartwool NTS Micro 150 Boxer Brief, Smartwool NTS Light 195 Boxer Brief

These are Smartwool’s lighter two weights of Merino in well designed boxer briefs. The difference in temperature range is little, and the only reason I select one over the other is when the temperature will be well over 90 degrees, in which case I will use the Micro 150. They are both form-fitting, with flat-lock seams, wool terry loop on the interior of the waistband, and fall to mid-thigh. The top of the waistband seam of the Micro 150 brief has become frayed after 10 washings, and may require reinforcement.

I cannot say enough about the comfort of Merino underwear. It is as soft next to the skin as cashmere, wicks well, never feels clammy even when wet and regulates temperature far better than other underwear. The surface finish of both the Micro 150 and Light 195 Merino is better than that of the Mid 250 Funnel Zip. The NTS Light 195 briefs are enthusiastically recommended, although the current Smartwool line contains only the NTS 150 Brief.
 

Other Merino Tops

Icebreaker GT200 Sprint Long Sleeve Crew

The Icebreaker GT200 Sprint is a crew-necked lightweight (200 g/m) T-shirt with extra-long sleeves and thumbholes, made from 96% Merino and 4% Elastane (Lycra). This legacy top is part of their technical series, and has an athletic fit, with slightly looser-than-normal arms, gusseted raglan sleeves and flatlock seams. It is available at a discount from various distributors. The top has a very smooth surface character and is quite comfortable next to the skin. The GT200 was originally acquired to act as a core layer under the somewhat scratchy Patagonia Merino specifically because of its comfort next to the skin and because the extra-long sleeves and thumbholes add hand protection, but it has become a go-to core layer when I am not wearing the WoolX array or in several truncated arrays (as have the Mountain Hardwear Integral Pro and Uniqlo Merino sweater described below).

By the way, for those who are interested in an extremely comfortable Merino T-shirt for use in very warm conditions, the Icebreaker Aero Crewe (a 90% Merino, 10% polyester 120 g/m featherweight running shirt) is nearly as soft as the WoolX, wicks as well and dries as fast as the Patagonia Merino 1 (although not as well as the Capilene 1), and is highly breathable.

Mountain Hardwear Integral Pro Long Sleeve Crew

The Mountain Hardwear Integral Pro is an unusual top, blended from 60% Merino and 40% Polypropylene. Its surface is quite a bit smoother than the somewhat scratchy Patagonia Merino/Capilene blend, and I acquired two of these to act as more comfortable core layers under the Patagonia Merino. The top is between silkweight and lightweight (about 140 g/m), and it has become a go-to lightweight long-sleeved layer for use alone in mild-to-warm conditions (especially climbing) as well as for its original intended purpose and as a light interstitial layer in some arrays. They are available at a discount from various retailers.

Uniqlo Extra-Fine Merino Crew-neck Sweater

The Uniqlo sweater is not a technical top, but is rather a standard clothing item from Uniqlo.com, a Japanese clothing manufacturer which happens to make a few items that are interesting for outdoor use. This is a midweight (roughly 220 g/m) traditional-style sweater that happens to be made of very fine-threaded merino which feels extremely good next to the skin. I use this in one or more arrays below the Patagonia Merino (with or without the Mountain Hardwear top). The sweater can be bought for $29.95 (!), makes a very comfortable core layer, and is used as a core base layer with both synthetic and Merino arrays. Their Dry V and Airism lines also make very inexpensive alternatives to synthetic technical tops, and their Supima cotton boxer briefs are excellent for hot weather use.

Bosque_delApache_Sunrise_4498_16x9


Bosque del Apache Sunrise 4498 16x9

A magnificent New Mexico sunrise paints clouds over the main pool at Bosque del Apache Wildlife Refuge.

WoolX Base Layers

The WoolX base layers are designed as a group to work in a lower temperature range than Smartwool or Patagonia products. In tops, they offer a lightweight T-shirt and a new long-sleeved Crew and Hoodie; midweights in Crew, Turtleneck and Zip-neck; and expedition weight in Crew, Zip-neck and Hoodie (they have two expedition weight Crew tops, one with extra-long sleeves with thumb holes). In bottoms, they offer lightweight briefs and long bottoms in midweight and expedition weight. I prefer using zip-necks to allow me to vent or retain body heat as needed, but when doubling up on layers in colder weather (such as wearing two midweight layers over a T-shirt) having the option of working with different neck heights is quite useful. WoolX uses 17.5 and 18.5 micron yarn weights.

WoolX uses a Mercerization process on their Merino wool. Mercerization was developed in the 19th century, originally for processing cotton, linen and hemp threads. The threads are bathed in an alkaline bath while under tension, then bathed in an acidic solution to neutralize the base. Bathing the fibers under tension causes the fibers to swell, increases the surface area and reflectance, and gives the fibers a softer feel. The resulting fiber is stronger, more lustrous and very noticeably softer.

The WoolX Merino has the smoothest surface and the softest feel next to the skin of the
Merino with which I have experience, and feels cool to the touch when you first put it on.

After several months of use in comparison to the Smartwool and Patagonia products, I have to say that I prefer the WoolX for its comfort, construction quality, and durability. If I am asked to recommend one line of Merino products, WoolX would be that line.

WoolX X302 Outback Lightweight 170 g/m T-Shirt

The WoolX X302 T-shirt is a lightweight crew intended to act as the core layer under one or more heavier layers, although it can be worn alone as the day warms up. In light to medium activity the upper temperature limit is 85 degrees in the shade or when worn under a field shirt. At about 80 degrees in direct sunlight, the T-shirt becomes rather warm when worn alone. The fact that it is only available in dark colors causes it to absorb all of the energy of the sun, which allows you to use it down to cooler temperatures before putting on another layer (or strip off the upper layer earlier). The T-shirt wicks and regulates temperature very effectively when used under another layer. This is the softest and most comfortable of the T-shirts next to the skin, but the dark colors and relatively dense weave makes it better for use in cool to warm rather than hot weather.

I used this T-shirt to test for odor retention and wore it under another Merino layer, alone under a field shirt, and by itself on five consecutive days in temperatures from 50 to over 90 degrees. After three sweaty days I showed it to my wife, who was shocked and amazed at the complete lack of odor. You could just begin to detect an odor on the morning of the fifth day, and it began to be objectionable in the afternoon of the fifth day after several hours at over 90 degrees. The odor was still less than that of the Under Armour HeatGear T-shirt after two hours at 90 degrees, but five days is the limit in my opinion. Merino base layers can be used for many days in succession and require less changes for a long trip than synthetics. These tests were purposely done at temperatures over the comfort limit... this T-shirt is not the one to wear at 90 degrees.

See the note below the Patagonia Capilene 1 T-shirt for the answer to:
“Why a T-shirt instead of a long-sleeved Crew, and which T-shirt is best?”

WoolX X304 Base Camp Lightweight 160 g/m Long-Sleeve T-shirt

The WoolX Base Camp Lightweights are made of 160 g/m material with a lower-density weave which lets more air through the material than the 170 g/m Outback T-shirt. The X304 LS T-shirt has deeply-gusseted articulated raglan sleeves which reach to the base of the hand and is exceptionally useful alone in mild-to-warm buggy situations, as a core layer when full-length sleeves are desired, or as a lightweight mid-layer. It is generally selected instead of the short-sleeved T-shirt when bugs are going to be a problem, although it is also useful as a lightweight mid-layer along with the X302 T-shirt.

I generally prefer a zip-neck mid-layer to allow venting heat when necessary, but the low-density weave of the Base Camp material allows enough air through to be comfortable when you are moving or when there is a breeze present. Generally, the X304 is chosen as a core layer instead of the X302 T-shirt rather than used along with it, in situations where full coverage is desirable. When used along with the X305 hoodie (below), both of which allow a fair amount of breeze through the weave, they make a highly complementary pair offering extreme comfort in mild to warm weather and give excellent protection from bugs. The X304 and X305 are good together into the low 50s... adding the X302 T-shirt would take the array down to the mid-40s, although in most situations I would prefer to work with a midweight zip-neck mid-layer in the 40s.

WoolX X305 Base Camp Lightweight 160 g/m Hoodie

The WoolX X305 Base Camp Hoodie is a lightweight made from 160 g/m material. The Base Camp Hoodie is a 1/4 zip with a traditional-style hood (unlike the semi-balaclava hoods of the Patagonia Capilene 4 and Merino 3 hoodies, the WoolX Base Camp Hoodie has a 3-panel hood which goes straight down the side of the face between the ear and the cheekbone). The contrasting zipper is welted on the interior (kissing welts) to prevent the zipper from contacting skin (or catching chest hair) and is exposed on the exterior. The tail is long, reaching to the hip joint, and the deeply-gusseted articulated raglan sleeves are also extra-long, with a flat-lock seam across the sleeve at the wristbone, a 2.5" sleeve extension beyond the seam which has a reinforced cross-over thumb opening, and a 0.5" smooth reinforced sleeve termination with flat-lock seam. The sleeve end stays in place over the back of the hand or can be fixed in place while reaching overhead or climbing by placing the thumb in the thumb hole. The thumb hole opening is reinforced with cross-over double-stitched contrasting Merino and is very comfortable (unlike the typical elastic band thumb retainers, this method does not pinch the web between the thumb and forefinger). The hood opening is also reinforced with contrasting double-stitched Merino, which helps to keep the hood in place.

The Base Camp Hoodie is unbelievably soft and can be worn directly against the skin by itself in mild to warm weather or as a core base layer, or atop one or more underlying layers. I acquired mine one size up to allow it to be worn atop either the WoolX T-shirt, the X507 midweight, or both. The material is a denser jersey weave than the Patagonia Merino 3 hoodie, and while it is a bit lighter it blocks a cool breeze as well, and offers almost the same amount of warmth. This is superb for cool to warm weather (or as an interstitial layer in cold weather) and is perfect to carry for cool mornings and evenings on very hot days.

The combination of the X302 Outback T-shirt and X305 Base Camp hoodie are comfortable into the mid 50s, and adding the X507 Explorer midweight would take you to the high 40s. Using the X304 as the core layer along with the X507 midweight and X305 hoodie adds 5-10 degrees. This is an exceptionally flexible and extremely comfortable layering array, and offers the best feel next to the skin of any array I have used. These temperature ranges all assume medium activity levels.

WoolX X507 Explorer Midweight 260 g/m 1/4-Zip Top

The WoolX X507 is a midweight zip-top with an exceptionally soft and smooth surface finish that feels cooler next to the skin than the Smartwool Funnel Zip or Patagonia Merino/Capilene tops. It was acquired in actual size, and it is superb at heat regulation and wicking, although both are improved when it is used along with a T-shirt underneath. For example, when it is used along with the X302 T-shirt, the combination has the same upper temperature limit as the X302 alone when used for low to medium activity (the X507 when used alone is good from 50 degrees, and reaches its limit at 75 degrees in direct sunlight and at 80 degrees in the shade or when worn under a field shirt). High temperatures like this are mentioned specifically to give a reference as to the temperature regulation capabilities of a top or array... normally you would strip the top off and change to a lighter layer or strip to an underlying T-shirt before you reached the limit.

The combination of the X302 T-shirt and X507 is significantly warmer than with the X507 alone, extending the lower end of the range downward to the low 40s. When I am starting out in the low 40s, until I have generated body heat I wear the X704 or the Smartwool Funnel Zip and Capilene 4 hoody on top (which set gets carried is based on how hot the day will be). For medium to high activity levels on days which will exceed 80 degrees I substitute either the Merino 1 T-shirt or the Capilene 1 T-shirt.

Keep in mind that your tolerance to various temperatures may be different than these guidelines.

This top is warmer than two typical synthetic tops, and does not retain odor even when worn for several consecutive days. It can replace those two tops and any changes which would have to be carried to substitute for those retired due to odor buildup. The X507 top has gussets under the arms which greatly increase mobility, and it is superb when climbing. Note: the 260 g/m X507 sleeves are somewhat short (stretch them when damp), although the new 230 g/m version has longer sleeves.

The WoolX X507 is, when used alone, cooler at a given high temperature than the equivalent Smartwool or Patagonia garment, and when each is used along with the WoolX X302 Merino T-shirt as a control, the combination of the X302 and X507 is also cooler than the X302 and the Merino 3 (either zip-neck or hoody) or the X302 and Smartwool NTS 250, thus my conclusion is that the WoolX X507 is superior to either of its competitors in temperature regulation, either with or without an assisting T-shirt. The weight of the Smartwool is slightly less (250 g/m vs 260 g/m) and the Patagonia is 220 g/m. However, both the Smartwool and the Patagonia products are more breathable than the WoolX, thus if there is a breeze, they will feel cooler. As both Smartwool and WoolX are 100% Merino, I assume the difference in performance between the two is due to the fact that the WoolX fits tighter to the skin than the Smartwool due to the size difference.

The X507 makes a superbly synergistic companion to the Patagonia Merino 3 Hoody in place of the Merino 2 Zip-neck. It is warmer in cold weather and it is far more wind-resistant, but it is less flexible as the temperature rises. The only downsides to the WoolX X507 are the short arms and that the substantial neck seam contacts the body at the zipper directly over the throat.

WoolX X704 Blizzard Heavyweight 400 g/m 1/4-Zip Top

The WoolX X704 is an expedition weight zip-neck top with deeply-gusseted, extra-long raglan sleeves which reach the knuckles and stay in place. It can act as a heavyweight upper base layer under an insulating layer in very cold conditions, an insulating layer in cold conditions, or a top layer in cool to mild conditions without the bulk of a typical insulating layer, and can replace at least three typical synthetics and any changes which would have to be carried to substitute for those retired due to odor. It is also quite useful as a top layer in milder conditions when used with only a Merino T-shirt. When used alone or with a T-shirt, it regulates temperature well up to 65 degrees (it wicks better when worn with a layer underneath). It is roughly as warm as two midweight Merino tops, and in my opinion this is one of the most versatile tops for use in very cold to mild conditions.

This is the top you want to put on when starting out in the morning before generating body heat, or when your body begins to chill as the activity level or temperature drops. The WoolX X704 is 2/3 as warm (with better neck protection and a far smoother transition of warmth from on to off) as the Under Armour Sherpa fleece hoodie (which was my standard insulation layer) at roughly a third of the bulk, and greatly outperforms heavy sweatshirts and most wool sweaters. It is not as good an insulation layer as a lofted jacket, but it has far more uses and requires less space in the pack. It can be used in such a wide range of conditions that the only reason not to take this top is when the temperature would be above its useful range (about 65 F.).

WoolX X509 Explorer Midweight 230 g/m Bottoms

The WoolX X509 midweight bottoms have a high-contoured back rise which provides extended coverage regardless of your movement or position and does not slip down, and along with the double-panel gusset allows for a wide range of movement. For those who have climbed in long underwear and experienced the typical “plumber’s exposure”, this will mean a lot. These bottoms are quite warm by themselves (warmer than silkweight and midweight synthetics together), and the Merino is soft and comfortable next to the skin. They are the go-to bottoms in cool to mild conditions. The only downside to these is that you can feel the flat-lock seams where the double-panel gusset and double-panel fly are if they are worn alone, but I always wear Merino underwear underneath so this is not an issue.

The WoolX X509 bottoms are good between the high 30s and 70. WoolX also has an Extremes 400 g/m version of these bottoms which I would think would extend the temperature range down well below zero F. when used with the X509, although I do not have a pair, preferring to work with multiple lighter layers. The Patagonia Merino 2 lightweight bottoms when used along with the WoolX X509 will take you down into the low 20s, and putting the Capilene 2 lightweight in between will take you down to zero degrees F. I prefer using the X509 next to the skin in either array due to the soft feel of the superb surface finish.

WoolX X303 X-Lite 160 g/m Daily Boxer Briefs

The WoolX boxers are lightweight jersey-knit boxer briefs with a 5" inseam which falls to mid-thigh, a double-panel gusset and a double-panel fly with flat-lock seams (which overlaps more than the other three brands creating a smaller opening... a possible consideration). They have a contoured back rise that provides extended coverage regardless of your movement or position and does not slip down, which along with the gusset allows for a wide range of movement. The 160 g/m Merino is lighter than that used in the WoolX T-shirt (slightly), and is not quite as soft until after the second wash (turn them inside-out or use a lingerie net). The fit of the X303 brief is superb. These are highly recommended.

Merino underwear is the most comfortable in both cold and hot weather in my experience, with excellent wicking and temperature regulation properties, and they resist odor for days (rinse as necessary).

Alaskan_Coastal_Brown_Bear_XL


Alaskan Coastal Brown Bear XL

Alaskan Coastal Brown Bear male and a Golden female at sunset,
taken at Silver Salmon Creek in Lake Clark National Park, Alaska.

Patagonia Merino Base Layers

Patagonia uses a Merino/Capilene blend for increased durability, to increase the wicking ability, and to reduce drying time over 100% Merino while maintaining odor resistance. Patagonia offers Merino 1 (silkweight) in boxer briefs, briefs, T-shirt and Crew, Merino 2 (lightweight) in a Polo, Crew, Zip-neck and bottoms, and Merino 3 (midweight) in a Zip-neck and Hoody. They use different blends depending on the weight and application. Patagonia Merino is an 18.9 micron yarn.

Patagonia was crafty in the design of their Merino/Capilene blend. From the tests I have done, 100% Merino is superior to the Merino/Capilene blend in temperature regulation: a lighter weight garment made of Merino/Capilene feels warmer when worn in a temperature near the upper limit than a heavier weight 100% Merino garment worn in the exact same conditions... but, if there is a breeze, the fact that Patagonia made their garments quite breathable means that it will feel cooler, as their products are all more breathable than the 100% Merino products with which I have experience. Also, since their products are lighter in weight, they are often worn in an array in conditions where you are either using a lesser number of 100% Merino garments, or wearing a single garment. The multi-garment array will work together synergistically to achieve superior temperature regulation. Crafty.

Like their Capilene products, the Patagonia Merino/Capilene line is designed as a group to work in a higher temperature range than the WoolX or Smartwool products, and is a thinner more breathable material. You can wear a particular array to a higher temperature than a similar array from WoolX, for instance, but to go to lower temperatures you will very likely need an extra layer or a heavier array, assuming the same activity level. The feel of the material is completely different than the WoolX, which is softer against the skin, has a smoother surface, and actually feels cool to the touch when you first put it on. The Merino/Capilene blend is still soft, but it has a somewhat rougher surface feel. Without the instruments to measure it, based on feel the Patagonia Merino/Capilene does seem to wick more rapidly than the 100% Merino products I have used.

Most wool fabrics are treated with chlorine to remove scales which make them itchy and cause them to shrink. Patagonia uses an environmentally friendly chlorine-free slow-wash descaling process, and the garments require washing before they soften. Even after a number of washes, the Patagonia Merino/Capilene blend is still considerably rougher than any other Merino products I have used, including the Mountain Hardwear 60/40 Merino/Polypropylene blend used in the Integral Pro. I acquired two of these silkweight long-sleeve crew necks primarily for use as a core layer under the Patagonia Merino, and unlike the Patagonia blend this blend feels smooth and comfortable against the skin. It is possible that my skin is a bit overly sensitive.

A technique which I have found to be extremely effective in softening rough wool is to soak the garment overnight in water mixed with hair conditioner, then wash the garment (in cold water) to remove the conditioner. After several months of using Patagonia Merino/Capilene products, I can safely say that they tend to shrink even when washed in cold water and hung to dry. I highly recommend buying these one size up. The Merino 3 tends to shrink more than the Merino 2 or Merino 1 from my experience. I have found that applying pressure atop the seam and stretching the damp top while it is laying on a flat surface works well.

Patagonia Merino 1 Silkweight T-Shirt

The Patagonia Merino 1 T-shirt is an ultralight Merino layer (120 g/m) that does not add much warmth but greatly improves wicking and temperature regulation to the layers above. It is quite breathable and can be used to fairly high temperatures. The WoolX X302 T-shirt (which at 170 g/m does add significant warmth to layers above) is reaching its limit at 85 degrees when worn under a field shirt at medium activity levels... the Merino 1 T-shirt is still going strong, and does not become warm under a field shirt in direct sunlight until about 95 degrees (I have worn it under a field shirt at 92 during medium activity and it was just beginning to get warm).

As mentioned, it does not add much warmth to layers above, so its selection as the core layer is best on days which start out cool but will reach into the upper temperature range, or when you plan high activity levels on a day which will be warm and you want a more breathable core layer. Its upper temperature range is below that of the Capilene 1 T-shirt and wicking is not as efficient (although temperature regulation is better... it is cooler in hot weather than the Capilene T-shirt, but less comfortable at very high temperatures where it tends to saturate), and its lower temperature range is significantly above the range of the heavier WoolX X302 T-shirt, but it breathes much better. The Merino 1 T-shirt is the middle choice as a core layer. With that said... I have two Merino 1 T-shirts and one each of the Capilene 1 and WoolX X302 T-shirts, and wear the Merino 1 T-shirt more often than either of the other two. The Merino 1 silkweight material is quite thin and can be easily damaged if it catches a twig or other object. Care should be taken when tucking it in and avoid brushing against rock or other objects if it is worn alone.

The attention to detail in the Patagonia design can be seen in the seam placement forward of the shoulders and sides to avoid chafing by the pack, and the extra piece of thicker black material below the inside of the rear neck seam, allowing you to easily determine the correct orientation of the T-shirt in any light... a nice touch.

See the note below the Patagonia Capilene 1 T-shirt for the answer to:
“Why a T-shirt instead of a long-sleeved Crew, and which T-shirt is best?”

Patagonia Merino 2 Lightweight Zip-Neck

The Patagonia Merino 2 zip-neck has a mock neck and a 12” zipper (with zipper garage) which reaches below the sternum. It is a relatively thin garment with long sleeves which cover the back of the hand, and elastic thumb loops which are attached inside the sleeve. The Merino 2 zip-neck is most useful as a core layer or as the second layer in an array over a T-shirt, as it is rather light (165 g/m). It is essentially a more breathable, long-sleeved, slightly less soft, zip-neck version of the WoolX X302 T-shirt. The Merino 2 is far more effective in both moisture transport and temperature regulation when used as part of an array. Alone, the Merino 2 is good for medium activity down into the mid-50s (after you are already generating body heat and assuming there is not much wind, otherwise low 60s), the addition of the Merino 1 T-shirt adds a bit of warmth but greatly improves the wicking and temperature regulation. The Merino 2 zip-neck is superb together with a Merino 3 top, and it is also quite useful as a light insulating layer between a Capilene 2 and 3 top in a cold weather array (as is the Merino 3).

Both the Merino 2 and Merino 3 are quite breathable, much more than the WoolX, which makes them more comfortable as the temperature rises with a breeze, but at the lower end of their temperature range that same breeze can make them a little chilly. See the notes under the Merino 3 Hoody below.

Patagonia Merino 3 Midweight Zip-Neck

The Patagonia Merino 3 zip-neck is a light midweight which is quite breathable. It has a higher neck than the Merino 2 zip-neck, and a 12.75” welted zipper (with zipper garage) so if the top is zipped down (or up) the zippers do not fall atop one another. It has long sleeves which cover the back of the hand, and elastic thumb loops. As is typical, it wicks and regulates temperature better when used atop another layer, generally either a T-shirt or the Merino 2.

In a test, wearing the black Merino 3 (with the neck unzipped) over a Merino 1 T-shirt with no field shirt, carrying 30 pounds at 80 degrees with a 6 mph breeze in direct sunlight, the array was warm but tolerable... I would say the upper limit without a field shirt is about 85, and with a light colored field shirt it is at least 90. In a two-layer array with the Merino 2 zip-neck, the Merino 3 can be used from the high 40s to about 75 or so (if there is a breeze at the bottom of its temperature range it can be a bit chilly, see the notes under the Merino 3 Hoody below). These are tests for the upper limit and to determine temperature regulation characteristics... usually you would take the Merino 3 off earlier depending on activity level.

The Merino 3 zip-neck is exceedingly valuable when it is used as an interstitial insulating layer between two synthetic layers such as the Capilene 2 and 3, adding about 20 degrees of warmth and improving the temperature regulation characteristics. The other primary use of the Merino 3 zip-neck is as the center layer of a 3-layer array, typically with the Smartwool Funnel Zip and the WoolX X305 Base Camp Hoodie. This makes an exceptionally flexible array for use from the low 40s up.

The Merino 3 zip-neck is not as warm as the WoolX X507, but as long as it is covered with a field shirt, it is more comfortable when used at a higher temperature due to the lighter weight and the fact that it lets a breeze in. In this respect, it is more like the Smartwool 250 Funnel Zip but of a lighter weight and with better wicking capabilities. The neck-to-body seam of the Merino 3 is far less substantial than that of the WoolX X507 and contacts the body below the throat, thus it is more comfortable.

Patagonia Merino 3 Midweight Hoody

The Patagonia Merino 3 Hoody is a versatile mid-layer with an anatomically-shaped hood, long sleeves which cover the back of the hand, and elastic thumb loops which are attached inside the sleeve. When the hood is up and fully zipped, it covers the upper lip falling just below the nose. When the hood is down but the neck is fully zipped, it can be folded over to make an exceptionally effective neck gaiter which can be pulled up over the chin if the wind is chilly.

The Merino 3 Hoody can be used as the top layer in a two-layer array with the Merino 2 zip-neck from the mid-40s (assuming no breeze) to above 80 degrees in the shade (with a light layer above such as a field shirt or the Capilene 4 Hoody to reflect the sun it can be used to the mid-70s in direct sunlight for low to medium activity). The Merino 2 and Merino 3 tops are quite breathable, and if there is a light breeze, the Merino 2+3 array is a bit chilly in the mid-40s without a shell or other layer on top. Adding the Merino 1 T-shirt adds a little warmth, takes the three layer array down to the low 40s and cuts the wind to the body core a noticeable amount. The Merino 1 T-shirt and Merino 3 Hoody also make a superb general-purpose 2-layer light array.

A note on the Merino 1,2,3 combination: when just starting out at the lower end of the temperature range (low-40s to mid-50s), before you generate body heat the breathability of this array can make it a bit chilly... add your shell or a midweight layer.

The temperature regulation of the Merino 2 zip-neck together with the Merino 3 Hoody is superb, and is improved further with the addition of the Merino T-shirt. The fabric thickness of the Merino 2+3 is about the same as the WoolX X507, but the combined pair are warmer, with better wicking and temperature regulation (although at a higher cost). If you put the Capilene 4 Hoody atop the Merino 2 and the Merino 3 Hoody, this array should take you into the 30s, most definitely if you wear a T-shirt as the core layer. The two hoodies together are quite toasty (the Merino 3 hood is slightly closer-fitting than the Capilene 4 hood) — if you don’t like stacking hoodies, use a Merino 3 zip-neck instead of the hoody.

The Merino 3 Hoody can be used alone as a light insulating layer atop a layer array, along with the Capilene 4 Hoody as a very flexible two-layer light insulation array, or you can add the WoolX X704 for a heavy two or three layer insulating array.

Patagonia Merino 2 Lightweight Bottoms

The Merino 2 Lightweight bottoms are about the same weight as the Merino 3 tops (215 g/m vs 220 g/m), but the blend is different (77% Merino, 18% Capilene polyester, 5% Spandex vs. 80% Merino, 20% Capilene polyester in the tops). They feel about the same weight as the Merino 3 rather than the Merino 2 top, thus you might consider these a midweight. They have a brushed elastic waistband, a fully functional fly and offset seams. They are lighter than the WoolX X509 bottoms (and a little rougher in texture), and heavier than the Capilene 2 bottoms (and quite a bit warmer). I used them under the Arc’teryx midweight pants at 45 degrees in a light wind (~15 mph) for medium activity, and this was approaching their comfort limit at this activity level for me. Below the mid-40s I would layer the Merino 2 with the Capilene 2 bottoms. The Arc’teryx pants are fairly light, and with heavier pants the temperature range would move down. Below freezing I would use them (with heavier pants) atop the WoolX X509, and to go to sub-zero I would use them as the top layer of a WoolX X509, Capilene 2, Merino 2 array.

Patagonia Merino 1 Silkweight Boxer Briefs

The Patagonia Merino 1 Silkweight Boxer Briefs feature a tagless brushed waistband and a 65% Merino, 35% Capilene blend. They wick and breathe very well and are quite comfortable. The Merino 1 brief is shorter than the Capilene 1 brief, reaching to the upper thigh. I prefer underwear that reach to mid-thigh as they do not tend to ride up into the hip joint when making high leg moves or squatting down with one or both legs, which tends to happen quite often as you know. They are superb in every other respect, and they get worn quite often, especially at higher temperatures. While the tendency to ride up is a minor annoyance, the Patagonia Merino 1 brief is the most comfortable of the Merino briefs in very hot weather.

With that said, after six months of use in a rotation of four Merino briefs, I have had to repair two half-inch holes in the Merino 1 brief that spontaneously appeared in non-stress areas, plus one in a stress area (I have also had to repair several holes in the Merino 1 T-shirts). After 8 months use, wearing them about 50 times and washing about 25 times, they have had to be repaired 10 times for holes in the fabric, most of which have not appeared near seams. I have not had this problem with any other Merino garments. The Merino 1 silkweight material is easily damaged, and it seems that threads can pop and a hole can appear without any apparent cause. While the Merino 1 is superb in hot weather, they will not last more than a year.

Surface Comparison Images

Merino_SurfaceComp


Merino Wool: Surface Comparison Images

The Patagonia Merino/Capilene and the Smartwool 250 are somewhat rough surfaces in
comparison to the Smartwool 195 and the WoolX X507, as can be seen in these images.

The rougher look translates directly into the feel on the skin. WoolX is the softest of the
Merino products in this dissertation, and the Smartwool 195 has the second best finish.

 A technique which I have found to be extremely effective in softening wool
is to soak the garment overnight in water mixed with hair conditioner,
then wash the garment (in cold water) to remove the conditioner.
 

The next section details usage of Outerwear, including Field Shirts and Pants,
Field Shorts and Knickers, Rain Gear, Softshell and Hardshell Jackets, and Hats.

Outerwear


Click to move on to the Outerwear page.

Layering


Click the Display Composite above to return to the Layering Index page.

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