Do moisture-wicking fabrics work?

good article thanks

one thing you mentioned in passing is that all the base layer fabrics had about the same, near zero insulation value.  it doesn’t make much difference which base layer you use

I am skeptical that wicking fabrics are useful, more just marketing hype.  I think your article is consistent with that.  But I’m open minded about it.

I don’t see how there’s any advantage to wicking the sweat away from my skin.  Whether the water is next to my skin or wicked into a mid layer, eventually it will have to be evaporated which cools me down.  The amount of cooling is dependent on the amount of sweat, not its location.

If the sweat stays on my skin, then I’ll be more aware of it.  Then I can remove insulation so I quit sweating.  So, wicking may actually be a disadvantage.

The key to moisture is to not have too much insulation so you don’t sweat.  Either remove insulation layers or unzip a full front zipper.  Or slow down and quit generating so much heat.

This is cold weather related.  If it’s hot that’s a different subject.

I’m re-reading your article several times.  Complicated subject.  Nice experiments and write-up – thanks

Testing brings back a lot of memories.  I worked for many years in the InkJet business and wicking is a key parameter both in ink delivery systems (foam) as well as ink absorbtion into paper.

Is ther an advantage to wicking moisture away from your skin?  Well, in humid conditions, silk is and ideal material to draw moisture away and keep you cooler.  Prior to all of the current synthetics, silk long underwear was very common.

That being said, wicking is a very complex topic.  My understanding is that sock design can be very intricate as the weave and pattern is designed to pull moisture up from your feet and out through the upper sections of your sock.  Crazy stuff.

Hi Jerry:

Do wicking fabrics work?  That is the $64000 question and, as I say in the article, one that will be addressed in a future article.    I hope people will discuss their experience with both summer and winter wicking layers–what might work, what might not work.  Thank you for reading and commenting!

This topic makes my head spin whenever I think about it. It’s so complicated. There’s wicking (liquid transport), vapor transport, evaporation, condensation – and it’s all happening at once at just about every point in the clothing system. The processes reach a semi-stasis at a constant output (exertion level), a new semi-stasis when hiking uphill, another one when hiking downhill, another one at rest.

The main thing I’ve learned in the winter is that nothing is constant, and the clothing system usually degrades (accumulates moisture) the longer you hike (even if you don’t “sweat” because you will emit vapor and that will condense as liquid moisture in your clothing layers in cold temps, and then your body heat will be sapped to evaporate it). So carry a dang big puffy for the end of the day, because that’s an important insurance policy.

My approach to winter layering is this:

1. I try to regulate my output (heat production) as much as possible. But if I’m doing something hard and fast, that’s impossible. There’s no option but to generate sweat. I can easily exert myself enough to sweat at 0 °F wearing fishnet and a windshirt if I’m carrying a pack uphill.
2. I use a wool base layer. It does not “wick” quickly. But here’s why I like wool as a base layer: its moisture capacity is high – but it absorbs the moisture into the cortex (inner hydrophilic core) of the fiber, not the cuticle (hydrophobic) outer shell (scales) of the fiber. That means it “feels” dryer against the skin, and that’s good for morale and comfort because it doesn’t distract me.
3. I *really* like using the Brynje super-thermo wool mesh baselayer underneath a Polartec Alpha Direct mid-layer. The big pores of the mesh allow moisture vapor to go into the midlayer, away from my skin. Again, this is a psychological comfort issue for me.
4. As long as I’m moving fast, I don’t really worry about moisture accumulation in my inner layers.
5. But when I stop to rest, or to camp, I have to carry more insulation (puffy layer) in order to slow the effects of evaporative cooling.

So I carry more weight than is necessary (high loft insulation layer) on trips where I have to move fast and sweat to meet some arbitrary objective I set 🙄

So to save weight on clothing: move slower, don’t sweat. That’s rule #1.

Selecting layers that “wick” the “right” way … I think that’s how Stephen is going to educate us in this series! Maybe that will be rule #2.

I used to wear shorts and short sleeve shirt in summer to stay as cool as possible

Then I switched to long pants and sleeves for sun and bug protection

Initially, the long sleeves and legs were annoying because they get wet with sweat.  And it seemed like I was getting hotter.

Except after a while I am thinking it doesn’t make me hotter.  The extra fabric will actually cool off a little from evaporative cooling so maybe it’s about the same.

If the fabric was wicking maybe it would be cooler?

I seem to remember an article on BPL about this a few years ago

excellent info.  Thank you.  I would be interested in learning more about fabric systems and how they work.  For example Paramo has a multi layer fabric it uses to push water away from you.  Does it work and how well?

Would like to have seen some other fabrics besides polartec tested.  Specifically curious about the phasic fabrics from Arcteryx.  I own several and they “seem” to perform quite well in my anecdotal assessment

Thanks for another good article.  In your future tests of wool it would be nice to compare alpaca.  I like alpaca plus bison down, yak and others.

Interesting, but sounds like article 2 will probably answer more questions :)

I do remember when Patagonia came out with their Thermal Weight base layers (I think it was named at least three different names- never quite understand why they do that).  I thought this will make a great mid-layer as often the older R-1 was simply too heavy.  The thermal weight didn’t make a great mid-layer at all and I thought I had wasted my $.  Then someone here mentioned that it makes a great base layer in cold conditions.  I was skeptical as I was in the camp of lightest base layer year round is what you want.  So I tried it.  Voila- a great base layer in cold conditions!

My go to base layers (outside of cold) are the (now discontinued) Patagonia Lightweight Capilene and OR’s Echo line, which God bless them they haven’t discontinued.  Upon casual examination, they look almost identical (and are pretty much identical in weight).

Please include one of these in further testing.

Thanks

Mike

HI Karl: Both Paramo and Buffalo are interesting systems.  I did a limited test on a Paramo  Ostro fleece and Bentu jacket several years ago.  Both are treated to be hydrophobic. Both pieces offered good MVTR.  The Bentu is a rather heavy microfiber wind layer.  It had decent HH for a wind layer. Air permeability is around 3 CFM/Ft 2, so good wind blocking.  The Bentu has very good breathability, most likely, due to its microfiber fabric.  I would say both pieces should offer good vapor transmission performance, but since they are treated to be  hydrophobic, I don’t see how they would wick.  If sweat evaporates on the skin or an underlying layer, the vapor may well escape through the layers as long as it does not encounter temperatures below dew point or freezing.  Then, mechanical ventilation such as pit zips may be necessary to allow vapor to escape.  I did not conduct wicking tests on these garments.

I have never seen a Buffalo Systems garment in real life.  I have looked at photographs of some of the garments.   The skin side can have the appearance of a fleece but it does not appear to be napped.  It appears  to be pile, which are yarns (collections of individual fibers) that unlike fleece or napped base layers, would contain well defined capillaries.  As such, they probably wick very well.

If anyone has examples of these systems and are curious about their performance, I am happy to look at them.  I would like to test a Buffalo systems pile jacket.  If you are interested in sending me one of these, just PM me.

Hi Randy:  Until your post, I had not heard of  Phasic. I thought maybe it had some cool Phase Change technology.  But, no.   I took a look at the Arcteryx website and it seems to be sort of like Patagonia Capilene which does not describe a specific fabric technology, rather a generic term for a base layer that might use a variety of technologies. In my brief look, I found references to bicomponent yarns, combinations of wicking and non-wicking fibers and just references to Phasic without any further explanation.   If someone wants to send me some Phasic examples, for testing, I am happy to do it.  I just need them for a few days.  PM me and let me know what you have.

By the way, I started with Polartec fabrics because I can buy them by the yard and they supply lots of brands and seem to incorporate a lot of the existing technologies.   Buying fabrics by the yard is relatively inexpensive and I can cut them up for R value testing on the guarded hot plate.  Testing finished garments is another story.  The test garments will have far higher costs and thermal performance cannot be tested without destroying the garment.

I am happy to test a wide array of brands and fabrics but someone has to provide them to me for testing.  If members have a particular wicking garment they want tested, PM me and prepare to live without it for a few days.  Of course, I will not be cutting it up for thermal testing.  The wicking/drying test and drop testing can be easily and quickly accomplished.

I recently went snowshoeing in 18-25 degree F temps with a Brynje merino wool layer under a 150 weight Icebreaker Cool Lite shirt. The Icebreaker outer layer was saturated over the areas of heavy perspiration, with moisture visible on the slim tendrils of the fabric, but in the same areas the underlying Brynje next to my skin was only very slightly damp.

The nice thing (or one of the nice things) about my Buffalo Systems jacket is that it has full length zips on the sides, with a velcro attachment at the bottom to keep it closed at the hem. So you can pretty much fully vent on the sides when really working hard.

When I did my winter trip with Ike in northern Michigan I wore a Montane Extreme Smock (similar concept as Buffalo) which I bought for the trip. It was much too warm when working hard (even in ~10-15 degree temps with a wicked wind that drove temps further down), so even with those zips open I’d sweat a lot but once we stopped and I put on a jacket everything, including me, was dry pretty quickly. (I sweat a lot easily and always have, I once did a winter dayhike up Mt. Si with my brother while it was lightly snowing/misting in ~25 degree temps wearing only a KUIU Peloton 97 shirt on my upper body and didn’t get cold until we stopped regardless of being quite wet and still sweating). I became a fan of the system after that trip with Ike, and bought a lighter Buffalo Systems jacket for winter use, as well as a pair of bibs.

Of course, being me, I haven’t used them as a system because I haven’t been on a true winter backpacking trip since I bought them. But I have no doubt they’d work great for someone like me. I need to use the jacket on a cold winter hike one of these days.

I’ve lost track with the what Paramo are selling now but have a number of Paramo items from around 15 years ago that I still wear during the shoulder seasons. The old single layer shirts I have certainly do wick. Pour some water on a hard surface and drop the shirt furry side down and water is drawn up onto the smooth outer side. It doesn’t spread outward by much but within a short time the inner surface feels noticeably drier than the outside. The fabric does become saturated fairly quickly but I’ve found that it does dry reasonably quickly if you stay active.
I use the thicker double layer fleece in winter though usually with a wool layer or two beneath it. I be had a layer of frost across the outside though suspect this is mostly from vapour moving through the outer layers.

I enjoyed the testing report though do wonder if placing the fabric over something that simulated a skin surface would be better than a sponge, after all a sponge is “designed” to hold on to water.

Hi Mike:  I thought article 1 was already long enough.  So,  more to come.  I wish I understood the naming conventions. I have two Polartec bottoms The other is a much lighter, loosely knit fabric.  Both are hydrophobic.  They don’t wick and, they work very well for me.  As I mentioned in the article, I don’t know if they started out hydrophobic, but they are now. The one in the photograph is a little warmer but much heavier than the one they label thermal weight.  Sort of like the 9110 style in the report.  The one called “thermal weight” is very light.  It is lighter and looser knit than either the 9076 or 9077 styles that I tested.  I am confident that if I cut the thermal weight (not willing to) and tested it on the hot plate, it would show less warmth than the 9076 or 9077 styles and a lot less warmth than the 9110 style. So, what does thermal weight mean?  I don’t have a clue.  However, I am confident that my Polartec thermal weight bottom is no warmer than one made from Power Dry 6000 or Delta Cool Mesh 6093 which are not marketed for warmth, just wicking.

So, does your thermal weight wick?  Mine does not.  Take a dropper and apply some drops and see if the drops are absorbed or just sit on the fabric.  With my thermal weight, the drops will sit on the fabric until they evaporate.

Hi Chris.  I appreciate your description.  Paramo makes two kinds of fabrics.  The first kind is rendered hydrophobic by application of Nik-Wax.  It will not wick until the DWR coating wears off.  At this point, Paramo recommends reapplying Nik-Wax.  The other type is called Parameta.  It is designed to wick and not rendered hydrophobic with Nik-Wax.  I would suggest, if you have a garment that was coated with Nike-Wax  that the coating has degraded.  Of course,  if it is Parameta, it is probably doing what it is supposed to.  You can read about this here.

Concerning the sponge.  You are clearly a careful reader!  The method of water application in a wicking test can greatly influence the results of the test.  I have tried a variety of materials and keep coming back to a sponge.  What I am trying to avoid is imparting energy or mass that exceeds what is available on the skin surface.   I think, by the way you worded your comment that you are concerned that water could wick out of the sponge and then back into the sponge.  It is possible, but remember, the way wicking works: wetting, capillary transfer, spreading and evaporation.  It it cannot evaporate, saturation occurs and wicking stops.  In the wicking test, to work in reverse, water would would have to move into the sponge and then evaporate into the environment around the sponge.  Since this environment has very high humidity and high temperature, evaporation and therefore backwards wicking is unlikely.  At some point,  one might expect the sponge to run dry. Then wicking would stop or possibly moisture move from the fabric to the sponge by diffusion.  I use a thick, large sponge that sits in a small pool of water, so it has a reservoir available to replace water that leaves the sponge.   If  any of these things happened drying would be seen in the thermal image occurring around the sponge perimeter. I have never witnessed this sort of behavior.  When I run the test for longer periods, drying always occurs at the kettle perimeter and works its way back to the sponge.  Sort of like watching the video in reverse.  The sponge never dries in the video.  If it did, the garment surface over and around the sponge would warm. It never has.  So, perhaps someone in the community can suggest another method and if it is something I can implement, I will try it.

Ryan…..What other ways do you use Polartec Alpha as a midlayer besides under a rain layer?

Stephen- I have both tops and bottoms (actually a couple of each) of the “thermal weight” Patagonia ones.  I’m assuming they’re wicking as the moisture is moving from inner to outer and leaving them  pretty dry, pretty quickly.  Possibly another action going on???

They aren’t overly warm, but definitely warmer then most light base layers (ie the Capilene Lightweight/OR Echo ones)

It seems to me. the article is discussing wicking materials and what a lot of people are interested is the overall water transportion on a system level and in particular during the winter.

I tend to agree with Ryan.  It seems to me the key ot to “Not Sweat”.  Wear multiple layers, and adjust dynamically.  It is almost like you want to never be warm, just cool and dry.  While the focus is on gear, a lot of moisture/water control is technique.

Here is an old article that was published in BPL years ago. https://gizmodo.com/how-the-navy-seals-prepare-for-extreme-cold-weather-sur-1737644998.  My understanding is that the of all the Navy Seals courses, the artic one is the most demanding.  It takes a lot of practice to adjust your clothing correctly in cold enviroments.  My 2 cents.

Good article but somewhat confusing in that VAPOR transmission has not been mentioned much.

I like polyester base layers and have different weights for different temperatures activity levels. Heavier weights DO insulate more, despite this article’s observations, unless I have misunderstood.

I want hydroPHOBIC base layers to let sweat vapor through the base layer to outer layers. Why do we say , “Cotton kills”? Precisely because cotton IS highly hydrophilic and keeps moisture next to our skin, cooling us dangerously.  Wool is somewhat hydrophilic itself when compared to polyester base layers.

“Part II” will be interesting to me if vapor transfer is addressed in more detail.

Hi Eric:  Thanks for reading and your comments.  Vapor transmission is of great importance.  I have discussed this at length in prior articles and it  will definitely be part of a future article.  I think wool vs polyester will be next up. Concerning warmth:   You can review table 2 and compare the warmth of different weights and construction of base layers.   My point is not that higher weights are not warmer.  They tend to be.  My point is that it is an inefficient way to keep warm for two reasons: 1) higher weights tend to reduce wicking performance (seen figure 9) and 2) The increase in warmth for the weight gain is inefficient (shown in figure 7).  The best course if you are using a wicking layer is to  to wear an excellent  wicking layer against your skin  and a mid layer that provides adequate warmth.

Hi Stephen

A very detailed article. Thank you.

The first photo in your article shows some brown Power Dry fabric. Interesting. I bought some of this fabric in 2007 or 2008 off-label at the local fabric shop. It was fairly cheap. See attached. A close-up detailed examination of my fabric shows exactly the same napped and knit appearance as your photos.

This was its first outing. The top has since been relegated to home use as it was not all that wonderful.

I wonder whether it was in production BEFORE Polartec decided to sell it as one of their products? It would seem extremely likely. Hum . . .

Cheers

Hi Roger.  I suspect I purchased both of my Polartec bottoms at a shop in Keane, NY, in the Adirondacks around 2015. So, I am guessing yours is not the one in my photograph.

One thing I learned from this project is that a lot of the Polartec fabrics look similar but perform differently.  And, of course, you can’t really guess how they perform by looking at them. At least I can’t, not even under the microscope.  I think among other things, their chemical treatments vary a good bit from style to style.  But the  pillar density and spacing can vary and the fibers can vary.

Of course, there are always a lot of knock offs of Polartec products.  They did not patent their original fleece, but now they have lots of patents, many of which have already expired.  Some of the knockoffs look like the real thing.  Others can be pretty readily recognized as not the real thing.

It would appear that your backpack is not consistent with ultralight backpacking!