Podcast Episode January 8, 2024

Podcast 95 | Natural Fibers in Outdoor Performance Apparel

Episode Sponsor

a computer generated image of a man in a suit and tie

This episode of the backpacking light podcast is sponsored by ARMS OF ANDES, manufacturer of premium base layer apparel made with alpaca wool. Backpacking Light podcast listeners can enjoy 15% off with the coupon code ALPACALIGHT at armsofandes.com.



In episode 95 of the Backpacking Light podcast we’re going to learn about the types of natural fibers that make up the fabrics we use for base layer and insulating apparel.

a couple of animals that are in the grass

In this Episode:

What’s New at Backpacking Light?

Featured Gear: Comparing the XTherm NXT and Nemo Tensor Extreme

Therm-a-Rest NeoAir XTherm NXTNEMO Tensor Extreme Conditions
Size Standard - Reg WideMummyRectangular
thickness3 in (7.6 cm)3.5 in (8.9 cm)
weight19 oz (255 g)22 oz (624 g)
packed size5 x 11 in (12.7 x 27.9 cm)4.5 x 10.5 in (11.4 x 26.7 cm)
top fabric30d nylon20d nylon
bottom fabric70d nylon20d nylon
insulationaluminized filmaluminized film
stabilityhorizontal bafflespseudo-square baffles
insulation constructiontriangular baffles made with reflective surfaces (isolate air movement)horizontal aluminized surfaces that allow for convective air movement up and down the length of the pad

Main Topic: Fundamentals of Natural Fibers

  • The primary differences between natural fibers and synthetic fibers – source, moisture management, thermal properties, durability, comfort and feel, odor resistance, environmental impact, care and maintenance, cost
  • New research on aerogel fabrics
  • Types of natural fibers:
    • Plant-based fibers – cotton, linen / flax, hemp, jute, bamboo, sisal
    • Animal-based fibers – wool, silk, cashmere, mohair, alpaca, mohair, angora
    • Mineral-based fibers – asbestos
  • Comparing the structure of plant-based and animal-based fibers – cellulose vs protein structures, microscopic structure, absorbency vs thermal properties
  • Unique characteristics of wool fibers – crimp, keratin-based, hygroscopic nature, thermal insulation, odor resistance, flame resistance, biodegradability, felting, dyeability, elasticity and comfort
  • Merino Sheep Wool vs Other Kinds of Wool – fiber diameter and fineness, crimp, strength and durability, comfort and feel, breathability and moisture management, odor resistance, price, and availability
  • Merino sheep wool vs Alpaca Wool – fiber texture and softness, warmth and insulation, weight, moisture wicking and breathability, hypoallergenic properties, durability and elasticity, odor resistance, price and availability, environmental impact
  • Comparing and Contrasting Huacaya Alpaca Wool and Suri Alpaca Wool


  • What’s the best baselayer that works with a waterproof-nonbreathable jacket like those from Lightheart Gear and Antigravity Gear?
  • What’s the difference between fishnet baselayers from Brynje and those from Wiggy’s and others?
  • Can fishnet be used in warmer temperatures?

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Share your tips, tricks, and questions on the podcast – submit it via email to [email protected].

Links, Mentions, and Related Content

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About the Backpacking Light Podcast


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  • Ryan Jordan - Director and Host
  • Chase Jordan - Producer
  • Look for Me in the Mountains - Music


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(Updated April 9, 2024)

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Home Forums Podcast 95 | Natural Fibers in Outdoor Performance Apparel

Viewing 14 posts - 1 through 14 (of 14 total)
  • Author
  • #3801086
    Backpacking Light


    Locale: Rocky Mountains

    Companion forum thread to: Podcast 95 | Natural Fibers in Outdoor Performance Apparel

    In episode 95 of the Backpacking Light podcast we’re going to learn about the types of natural fibers that make up the fabrics we use for base layer and insulating apparel.

    Ryan Jordan


    Locale: Central Rockies

    Ten years ago, I mostly opted for wool because it was so good at resisting odors (still is). Synthetics have gotten much better for long-term wear since about 2018, but still have a ways to go. I’m still not a fan of wearing clammy base layers, so I still lean towards wool (often with a fishnet layer underneath). Has anyone else been wearing wool historically and gone back to synthetics? Or vice-versa?

    BPL Member


    Locale: The West is (still) the Best

    Doing some research (reading) for a just completed merino wool purchase, the knock on merino is still durability especially under pack straps according to the reviews. Another fairly new company has their merino a little thicker, but will it start affecting hot weather hiking temperature? Probably individual.. Some articles (mostly climber based) point out that merino still holds water vs synthetics, but most “merino” are blends.

    Still feel the durability especially where a pack abrades against fabric should be addressed (but it won’t be).

    I plan on using my second merino as a sleeping shirt to take advantage of its comfort range and only use for hiking in case of emergency.
    Also just ordered some merino socks from a well-known company  and while socks must have nylon, it seems the nylon content is slowly going up %-wise.

    David D
    BPL Member


    Wool doesn’t feel clammy but when I stop and its very cold, I feel like I’m wearing a comfy but dangerous sponge.  For me, it holds too much water.

    I’ve switched to Brynje mesh under tight fitting Lifa.  It manages sweat much better (allows it to escape) and the tightfitting Lifa adds a lot of warmth with the air trapped in the mesh.  Stopping doesn’t feel as dangerous and my skin doesn’t feel as cold after a long winter day hike.   Drawback is wind cuts right through the combo easier.  I might add a cheap Dooy for when the wind is howling.

    Terran Terran
    BPL Member


    I usually wear a layer of Great Pyrenees over any wool or fleece., I read it can be 80% warmer than sheep’s wool. I prefer the alpaca wool. I’ve been wearing bison wool socks for a few years. I have some (unfortunately discontinued) thin wool/silk blend socks for warm weather, otherwise I prefer synthetic.. I like a thin layer of wool for warmth. I can shrink it for a better fit. Synthetic fleece over that to deal with the elements better and to add loft to a hard shell.

    Bill Budney
    BPL Member


    Locale: Central NYS

    I usually wear a layer of Great Pyrenees over any wool or fleece

    I can’t figure out whether that is a joke, a typo, or a name brand that I haven’t heard of.

    Slightly unsure that I want to ask.

    Terran Terran
    BPL Member


    The perils of dog ownership and wearing fleece. Great Pyrenees mix.

    Mark Ferwerda
    BPL Member


    Locale: Maryland

    I Just finished listening to this podcast. Regarding the environmental impact by sheep, I always thought the biggest impact by sheep was that they tend to strip the land of vegetation by nibbling down to the roots.  I thought that was why the cattle ranches of the 1800s hated sheep so much. Cattle did not overgraze like sheep did…

    Terran Terran
    BPL Member


    Cattle can overgraze as well if allowed to. You end up with an accumulation of parasites that affect cattle but the sheep can handle them. Sheep can go in where cattle have grazed. The pasture can be then overgrazed or cleared depending on how you look at it. While the cattlemen were following best practices and rotating fields, the sheepherders, who were a bit more desperate, would take advantage of the fallow pastures, thus giving sheep a bad reputation.

    Mark Ferwerda
    BPL Member


    Locale: Maryland

    Thanks for the added info!

    Whit W
    BPL Member


    I really want to like merino base layers, but in my experience trying to use merino base layers from both montbell and smart wool, they fall apart quick- in the case of my montbell merino shirt, I bought it for a 4-day ski touring trip and after the trip I had holes on both shoulders. The smart wool layers held up a bit better but still not well. I have some costco poly base layers that I used intermittently for 5 years and regularly for another 5 years after that, and are still going strong. It’s hard for me to justify the premium price of merino layers and the increased frequency I’d need to replace them. If I could trust natural base layers would last the same way polyester ones do, I’d probably be willing to pay a premium to stink less and wear less plastic.

    Funny enough, the exception to this experience is socks. My merino socks seem to last a lot longer than polyester ones, though that may be because poly socks I own are cheap ones from target. Regardless, the comfort (and minimal smell!) of wool socks has been an obvious improvement over synthetics for me.

    Bill Budney
    BPL Member


    Locale: Central NYS

    Has anyone else been wearing wool historically and gone back to synthetics?

    Late answer to Ryan’s original question: I wore wool for many years, sometimes cotton in Summer. For at least a decade I’ve been wearing synthetics. As discussed in other BPL articles, synthetics are objectively better at handling moisture.

    That said, the natural fibers work well enough, and it’s mostly a matter of personal preference.

    Brynje does add a smidgen of comfort in cool weather. I like it, although it doesn’t replace any other layers. I cannot figure out how people wear it in Summer, though. It adds warmth, no matter what I wear over it.

    Nick Gatel
    BPL Member


    Locale: Southern California

    I’m still not a fan of wearing clammy base layers, so I still lean towards wool (often with a fishnet layer underneath). Has anyone else been wearing wool historically and gone back to synthetics? Or vice-versa?

    Synthetics for decades, starting with polypropylene over 40 years ago. Then moved to Capilene a few years later.

    Around 15 years ago I switched to wool. And some merino/poly blends. Problem with these is they wear out too quickly. The blends worked better, but are hard to find. After five years of wearing out expensive merino, I went back to Capilene — better ROI — less junk going into landfills if that is a concern for people.

    (above BPL Beartooth Merino Hoody in 2009). I really liked this, but it wore out fairly quickly.

    Pretty rare for me to get a clammy feeling with Capilene, which is probably a mixture of my physiology (I don’t sweat as much as most people) and getting the right combination of layering to meet the conditions.

    Steve Thompson
    BPL Member


    Locale: Southwest

    After some trail and error I settled on wool, or wool blends after my 2009 JMT hike.  On that hike every body part touched by synthetic fabrics (upper body where my t-shirt sat, where the liner in my baggies touched, and my feet) broke out in a horrific heat rash.  I can contain it with application of cortisone and antifungal creams, but with natural fabrics (wool, cotton, viscose, bamboo fabrics, etc.) it never develops.

    Not sure why I needed to be 52 years before it started, but age evidently has something to do with it.

    Anyway, wool and wool blends dry faster than the other natural fabrics and though they cost more and wear quicker the lack of rash and painful pustules make it well worth the spend.

Viewing 14 posts - 1 through 14 (of 14 total)
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