The wool side
Wool keeps working while you sleep.
Wool takes up to 30 percent of its own weight in moisture before the surface ever feels damp, which is why you wake dry on a night that would have left you clammy. It gives off a little heat as it takes moisture in and draws heat as it releases it, so it evens out the swings instead of trapping them.
Ours is long-staple, each strand 3 to 5 inches, about twice the length of the wool most pillows use. Longer fibers tuck their scratchy ends away, so the surface rests soft against your cheek for years where cheap wool prickles and pills.
30%of its own weight in moisture, held before it feels damp
3 to 5 instaple length, about twice the usual