Up to 40% warmer than Merino
A number of independent tests have shown yak wool is between 10 - 40% warmer by weight than equivalent merino wool. Yaks live at extremely high altitude on the Tibetan Plateau as well as in countries such as Kyrgyzstan, Tajikistan and Mongolia. Having adapted to living at altitudes up to 5000m and enduring winter temperatures down to -40C, compared to NZ Merino sheep who live at around 1000m and relatively mild winter temperatures, it is no surprise that the soft undercoat fibers from a Yak make for an incredibly warm fabric.
A warmer fabric means you can wear lighter clothing, giving a more comfortable feeling and allowing for greater freedom when you are out adventuring.
Higher breathability and wicking ability
The fibers from yaks are hydroscopic fibers, which means they have the ability to absorb, transport and desorb moisture to and from the vapour phase. Water vapour between your body and fabric is absorbed into the fibers and transported to the outside of the fabric before being desorbed to the atmosphere. The fibers also have the ability to store water within their structure creating a buffer between you and the varying humidity conditions of the surrounding environment. According to a test of yak fabric it was shown to be 66% more breathable and have 17% better wicking characteristics. The result is a garment that keeps you at the right temperature no matter whether it is cold, hot or you are doing intense activity.
High resistance to static
Static electricity build-up results in the garment clinging to the body and reducing comfort. Yak wool has a high resistance to static because it can absorb a large proportion of its own weight in water (an inherent quality of the fiber) and water has been shown to prevent the build-up of electrical charges on various materials. The incredible wicking ability of yak wool directly translates to a high resistance to static.
Yak-like Strength and Flexibility
Yak fibers have high levels of sulphur based proteins and amino acids in the fibers giving it a high strength to fineness ratio. It also has a high resilience to bending and can be folded thousands of times before breaking. This combination of strength and flexibility is perfect for outdoor clothing that demands a comfortable and well formed fit while being worn in a range of demanding conditions and environments.
Soft and itch-free
Yaks wear a double coat; a long, coarse overcoat to protect it from rain, snow and ice, and a short, fluffy undercoat to provide insulation during fierce winters. Only the ultrafine down fibers from baby yaks are used to make clothing. Yak down is soft for a few reasons. Firstly, the fibers are extremely fine, generally having a diameter between 17.5 and 19 microns, and comparable to superfine merino. Secondly, yak fiber has a large amount of crimp making it soft, fluffy and light. And lastly, under a microscope yak fiber is scaly and smooth which translates to a soft smooth feel in the fabric and can be compared to mercerised merino which needs to be chemically processed to have the same smooth fiber texture.