Gear Skeptic Baselayers

Started watching, not sure his approach is gonna make sense here.  Watched his Brynje conclusions and they don’t match my field experience at all. Maybe human sensations aren’t quantifiable by the metrics he’s using.

Watched his Brynje conclusions and they don’t match my field experience at all

It’s been a few days since I watched it, so I don’t remember his wording exactly. Seem to remember him saying something to the extent of Brynje being so different that it doesn’t compare 1 to 1 with the rest.

It does kind of highlight the problem with objective testing though. Controlled, verifiable tests are  reductionist by nature, while actual use is subject to a complex mix of parameters.
While I probably didn’t come out on the other end knowing much more with regards to what will be the best and worst products for me, it was a well made video and an interesting data point to further my understanding of how different characteristics can be between fabrics that are very similar on paper (polyester vs polyester).

he said that simulations are better for comparing different clothing but not so good at comparing to reality.  For example, they have sweating manikins but argue about whether the details matter, like how many body parts there are and how they simulate movement of the manikin in the test vs actual humans.

There is no direct human perception of wetness.  You can feel clamminess where the fabric sticks to your skin, and you can detect cold temperature.  Fishnet has holes in it so there is less area contact between fabric and skin so it feels better.

One thing he said that resonates with me was that he likes his base layer to be able to function by itself when conditions dictate, so he wants it to have sun and bug protection.  Tight weave to accomplish that.

Another thing he said was that you should control sweating by slowing down or removing insulation, but that in some cases, you can’t just slow down, then maybe which base layer you have could be more important.

Another thing he said was the thicker the fabric is, the more water it can absorb, which makes it take longer to dry, so you want thin, light weight fabric.  Fishnet not quite so good.

Yeah, he didn’t say much that I didn’t already know, but more data about it to understand better.  For geeky people : )

Just for kicks, I asked Gemini to summarize:

The video “Outdoor Clothing Theory, Part 1: Base Layers” by GearSkeptic provides a comprehensive, data-driven analysis of how different base layer materials and designs handle moisture during cold-weather exertion.

Core Philosophy: Behavior Over Gear
The video emphasizes that the best way to manage sweat is through behavior, not just clothing:

Slow Down: If you are sweating, you are either moving too fast or overdressed [00:56].

Shed Layers: Be proactive about removing hats or opening vents before you become saturated [01:26].

The Buffer Rule: Think of your base layer as a “buffer” to manage small mistakes in pacing, rather than a “sponge” to soak up heavy sweat [03:32].

Key Scientific Findings
The creator tested 17 different shirts—ranging from cotton to high-end synthetics—to measure wicking and evaporation.

Thin and Open is Best: For a layering system, thinner fabrics with an “open weave” (mesh-like) generally outperform dense knits because they maximize airflow and dry faster [06:54].

Wicking vs. Drying: Fast wicking does not always equal fast drying. For example, some “clover-shaped” fibers (like Montbell’s Wickron) wick incredibly fast but can hold onto water longer than a simple mesh [39:46].

The “Fishnet” (Brynje): While popular, “fishnet” polypropyle layers are highly specialized. They keep the skin feeling dry by reducing contact, but they are mediocre at actual evaporation and lack versatility (no sun protection, low modesty) [41:57].

Wool vs. Synthetic: In the specific scenario of high exertion leading to saturation, wool can actually be a liability. It absorbs more water (high fiber regain) and takes much longer to dry than a high-quality synthetic mesh [19:21].

Performance Standouts
The Winner: The Montbell Zeoline Cool Mesh was the top performer in the test, offering the best balance of light weight, effective wicking, and the fastest evaporation rate [41:22].

The Disappointment: Several expensive “name-brand” synthetics (like certain North Face FlashDry models) actually dried slower than basic cotton in the test, often due to high elastane/spandex content which holds onto moisture [38:21].

Construction Matters: Avoid high spandex/elastane content (often added for “stretch”) if your goal is fast drying, as these fibers are inherently more absorbent [40:41].

Shopping Advice
When looking for a base layer for cold-weather activities:

Seek Porosity: Hold the fabric up to the light; you want to see an open, mesh-like structure [26:12].

Go Loose: A looser fit allows for “forced convection” (air pumping through the shirt as you move), which significantly aids evaporation compared to skin-tight “compression” fits [12:28].

Check the Tag: Aim for 100% polyester or polypropylene. Avoid blends with significant amounts of spandex/elastane if quick drying is the priority [40:41].

I dunno.

Just did a long hard 3 days including 1 in long rain and hail in the low 40s

I don’t slow down to stay dry

My shirt was moderately damp in sweat under my poncho but I was warm, comfy and dry in my brinje base while moving and after swapping shirt for octa+ad120 in camp

Never took brynje off over 4 days, even slept in it.  Always felt dry and comfortable

Theory will take you so far, but I’ll take real world experience over theory any day

“I don’t slow down to stay dry”

and that shows the limits for the strategy of slowing down to reduce sweating.  Doesn’t work in some cases.

“Theory will take you so far, but I’ll take real world experience over theory any day”

It seems like another strategy for measuring this would be to instrument real people.  Or even just recording what you wore, result, how warm it was, how strenuous you were hiking, how much it rained.

If I don’t record specifics, I won’t remember very good how good something worked.

The “Fishnet” (Brynje): While popular, “fishnet” polypropyle layers are highly specialized. They keep the skin feeling dry by reducing contact, but they are mediocre at actual evaporation and lack versatility (no sun protection, low modesty) [41:57].

Going off the AI condensed version. I believe it’s correct.

Moisture passes over and thru the mesh to the next layer where it evaporates or you change your shirt. It aids in the expulsion rather than the evaporation..

I never find the brynje feels wet, ever, but I constrain it’s use to below about 15c.  And I sweat

I try hard to not have clothing that dictates pace, and I experimented with many base, mid and wind shirt combos from -30c to 15c.  For me, the brynje and dooy are the secret weapons that let me set my own pace and all the other layers (lifa, octa, AD, sometimes soft shells of various weight, nylon full button silver ridge light, echo) work around those

I record all my layering results, the permutations and combos would be impossible to remember!

My pace dictates my choice in baselayers that dictate my pace.

Not sure how pace does not affect layering. It has to be related to energy expenditure. In remembering the article about how the Marines do Arctic training, it all had to do about layer management. Net result was to never overheat, stay on the cool side. If you’re comfortable, you have too many layers on.

Pace affects layering but by using the brynje and dooy I can always find a mid combo below 15C that keeps me feeling dry, pace be damned.  For me at least, HYOH and YMMV etc.  Above 15C I throw on the echo alone and you get what you get, its the lightest layer out there with sun coverage and no need for a base at those temps

The “Fishnet” (Brynje):…………..no sun protection, low modesty

The few drawbacks Gemini points out (or GS to be fair) is only really an issue in the summer/warm season. It limits the use of PP fishnets to the colder season(s) for me (and most others I assume), but then again it truly shines in those conditions.

The above is also why I outright dismissed fishnet t-shirts for many years. But last summer I started experimenting with using an Aclima wool fishnet t-shirt as a base layer under my synthetic button up sun shirts.
Last summer wasn’t much to talk about, so the experiment hasn’t logged enough data points to even form a preliminary conclusion yet. I expect it will be too warm to be useful in really warm and sunny weather, but here in the middle region of Norway we have a lot of varied weather and even days that aren’t excruciating hot yet still offers intense sun exposure.
My hypothesis is that the wool net could improve comfort by preventing the clammy polyester fabric from sticking to my skin. While the max comfort temp is probably reduced a bit, the comfortable temp range is hopefully increased a bit. By mostly eliminating direct skin contact I also hope to increase the time it takes for my shirt to develop a smell as well as reducing the ability for bugs to bite through.

Regular sun hoodies are still my go-to for fast paced hiking in sunny weather. The button up approach is intended more for varied hikes where I maybe stop to fish for a while, and/or move between open, hot, exposed areas and more protected patches of forest with cooler air and more bugs. Hopefully the upcoming summer will provide many days of suitable test conditions (still in the single digit C’s though)