To avoid blisters it is important to wick away any moisture in the shoe - especially while hiking. Wool is excellent to wick the moisture and if the sock does get wet (rains in Appalachian area!) wool will still keep the feet warm. Cotton dries very slowly - think about line drying a pair of jeans/bath towel. Yes, the hiking word is "cotton kills" since it stays wet and cold pulling heat from your body. ok, back to knitting.