Acorns are edible, but often contain large quantities of bitter substances. White oak acorns usually have a better flavor than red oak acorns. Gather and shell the acorns. Soak the acorns in water for 2 to 7 days, changing the water twice daily, to remove the bitter substance. Boil the acorns or grind them into flour and use the flour for baking.
Tannic acid gives the acorns their bitter taste.
Eating an excessive amount of acorns high in tannic acid can lead to kidney failure. Before eating acorns, leach out this chemical through soaking. The seeds of all Pine tress are edible. Pull apart the pine cone to get to the seeds. Pincushion Cactus are a good source of water in the desert.