Silberman shares that the fiber type and finish will contribute to a blanket being the softest. "Cotton's hand is soft and smooth and has a 'dry' (natural) hand. Wool has scales on the fiber, so it might be a little scratchy, however, there are breeds of sheep that are bred for fewer scales, which yields a smoother hand (less scratchy)." However, blankets are finished either chemically or mechanically to make the product softer. An example of a type of finish is flannel or silicone. Therefore, it may be helpful to look into the finish of your fabric to determine the softness, but cotton and wool are great options for those looking for a soft blanket.