Why Yak Clothing Is So Warm And Soft

What Is Yak Clothing?

Wool comes in many different forms with different feel and function.

Animals in the families of sheep, goats, yak, camel, and even ox produce a fiber broadly called “wool”.

No synthetic comes close. Wool is the best-performing material we know of, and khullu is the finest of it.

Khullu, the foundation of our yak wool clothing, comes from the soft underbelly fibers that insulate yaks through the cold winter.

Our materials helped us make both a warm and highly breathable sweater.

How Warm Is Yak Clothing?

Yaks grow a thermoregulating fiber called khullu, and they live in a high-elevation climate that swings from -40°F in winter to 90°F in summer, so the same fiber keeps you warm in the cold and cool in the heat.

Unlike human hair, wool has crimps, which are natural “waves” in the fiber that trap air to insulate in extreme cold and wick away vapor to cool in extreme heat.

Wool can be regarded as an ‘active’ fiber, which keeps body temperature at an equilibrium. It efficiently transfers water vapor from sweat in and away from the body as temperatures change.

In fact, as wool transfers water vapor, a chemical reaction occurs that produces heat.

Even the desert-living Bedouins wear lightweight wool clothing like ours to keep themselves cool.

Is Yak Wool Itchy?

No. Whether a wool itches comes down to how fine the fiber is. Coarse fibers are stiff enough to prick the skin, while finer ones bend against it.

Wool starts to feel soft below 20 microns. Khullu measures around 17.5 microns, inside the 14 to 19 micron band that Grade A cashmere occupies, so a yak wool sweater can go straight on over bare skin.

Does Yak Clothing Hold Odor?

No. Wool pulls sweat off the skin before bacteria can turn it into odor, so a yak sweater stays fresh after days of wear.

Wool is antimicrobial, and that starts with the material’s wicking properties. To regulate body temperature, humans can sweat several liters a day.

All this sweat can get pretty smelly, right? In fact, sweat only becomes odor if it isn’t wicked away.

Wool has a number of unique moisture management properties that allow it to resist body odor, making it ideal for #repeat wear and simplifying your life.

Saturation regain: wool can absorb and retain up to 35% of its own weight in moisture and still feel dry to the touch, which reduces sweat buildup and discourages bacterial growth.

Isolation of bacteria: after sweat is absorbed from the skin’s surface, it travels outward, where it evaporates. In the process, wool actively binds and isolates bacteria within its fiber.

The isolation of bacteria reduces odor to the point where unwashed wool has 66% less odor intensity than plastic-based fibers and 28% less than cotton fabrics (Woolmark).

Fun fact: bacteria thrive in humid environments, where sweat is trapped instead of being wicked away. For example, while a 1x1cm area on a human forearm contains around 100 bacteria, an identical square in the armpit contains on average 10 million bacteria (Popular Science).

The odor-resistant properties of wool allow clothing to be washed less and worn more, and it stays fresh even after the 10th wear. You may travel with wool layers for just this reason.

How Long Does Yak Clothing Last?

For years of regular wear, and often for decades when a sweater is well made. The reason is the way a wool fiber is built.

The crimps in wool are akin to a molecular coil spring. The fibers naturally expand and contract according to their environment.

The crimps allow wool fibers to be stretched up to 50% of their length when wet and 30% when dry and still bounce back to their original shape, so a sweater keeps its fit at the cuffs and elbows.

The flexibility gained from wool crimps makes the fiber more durable. A wool fiber can be bent back on itself more than 20,000 times before it breaks, against about 3,000 for cotton and 2,000 for silk (American Wool). That is what holds a sweater together wash after wash.