The following was adopted from the awesome Sierra Trading Post. Check it out here: “The Wool Guide.” Sierra Trading Post, http://www.sierratradingpost.com/lp2/wool-guide/.
To begin, it helps to understand some of the benefits that all types of wool offer. Wool has several characteristics that other natural fibers like cotton and linen simply can’t compete with.
Wool is water resistant.
Unlike human hair or animal fur, wool fibers are actually hollow with a durable, flexible and water-repellent exterior. The structure of wool fibers is composed of small, overlapping sections, kind of like shingles on a roof. Each fiber’s core absorbs up to 30% of its weight in moisture vapor without becoming damp or clammy. Meanwhile, the hard outer layer protects against outside moisture from rain and snow.
Wool wicks moisture.
Aside from blocking most external moisture, wool fibers wick perspiration away from the body. Normally, as your sweat evaporates, heat is drawn away from your skin. This effect is comforting in hot weather, but can dampen your clothing and give you chills in colder weather. Unlike cotton, which absorbs moisture and tends to remain wet, wool actually wicks perspiration and allows it to evaporate quickly, thus keeping you warmer.
Wool is a wonderful insulator.
Wool fibers are not perfectly smooth or straight. Instead, they’re crimped, which helps produce tiny insulating air spaces that retain more heat. In a way, wool functions similarly to the puffy fiberglass insulation inside the walls of a house.
Wool is breathable and regulates temperature.
Wool has a wide comfort range, which is very helpful for adapting to changing weather conditions. This unique property makes wool the perfect fiber for crafting outerwear and insulating apparel, since it has the ability to provide warmth in colder conditions and also breathes well as temperatures warm up.
Wool is naturally odor-resistant.
You may have noticed that synthetic fabrics like polyester and polypropylene can begin to retain odors over time. Wool is much more resistant to retaining odors. Sheep’s wool is also naturally resistant to wrinkling and static.