Pick up several cupfuls of acorns. All kinds of oaks have edible acorns. Some have more tannin than others, but leaching will remove the tannin from all of them. Shell the acorns with a nutcracker, a hammer, or a rock. Grind them. If you are in the woods, smash them, a few at a time on a hard boulder with a smaller stone, Indian style. Do this until all the acorns are ground into a crumbly paste. If you are at home, it's faster and easier to use your mom's blender. Put the shelled acorns in the blender, fill it up with water, and grind at high speed for a minute or two. You will get a thick, cream-colored goo. It looks yummy, but tastes terrible.

Leach (wash) them. Line a big sieve with a dish towel and pour in the ground acorns. Hold the sieve under a faucet and slowly pour water through, stirring with one hand, for about five minutes. A lot of creamy stuff will come out. This is the tannin. When the water runs clear, stop and taste a little. When the meal is not bitter, you have washed it enough. Or, in camp, tie the meal up in a towel and swish it in several bucketfuls of clean drinking water, until it passes the taste test. Squeeze out as much water as you can, with your hands. Use the ground acorn mash right away, because it turns dark when it is left around. Or store in plastic for freezing if you want to for later use.