Humans can enjoy acorns, too, although they take quite a bit of preparation to render them digestible. They must be treated because they contain tannins which make them bitter. Acorns should be gathered when they are green and ripe but before worms get to them or they rot or sprout. They are an excellent source of calories and protein. Acorns gathered from white oaks, with rounded leaves, are generally sweeter than black oaks, which have pointed leaves. To remove the bitterness, boil them whole or coarsely chopped for a long time, sometimes a couple of days, until soft. Change the water often. Another method is to chop the acorns fine and tie them in a clean cloth, such as a T-shirt or a sack and fasten it to a shower head or faucet. Trickle cold water through the acorns for a day or two. The resulting meal is nutty tasting and can be made into porridge or mixed with wheat flour to make bread. Invite a squirrel to lunch! Acorns and acorn meal must be kept dry in a tightly sealed container or it may ferment.