Oak (Acorns)

Quercus rubra · also: oak, red oak, chêne

How to ID it

Lobed leaves; red-oak group has bristle-tipped lobes, white-oak group has rounded lobes
Acorns sit in a scaly cap; collect only mature brown nuts, not green
White-oak-group acorns are less bitter (lower tannin) than red-oak-group
Reject any acorn with a small exit hole — that's a weevil

Safety

Acorns are safe once leached — never eat them raw. Raw acorns are loaded with tannins: astringent, and hard on the stomach and kidneys in quantity.
Leach with repeated cold- or hot-water changes until the water runs clear and the nut no longer tastes bitter. Red-oak acorns need far more leaching than white-oak, but both are good once fully leached.

Harvest

Gather mature brown acorns off the ground in fall. Float-test at home: drop them in water and discard floaters (bug-damaged or dried out). Shell the sinkers — a slit and a squeeze pops most caps and shells off.

Prep

Leaching is mandatory. Cold leach: grind the nutmeats coarse, soak in cold water, change the water daily until it stays clear and a taste is no longer bitter (days for white oak, up to a week-plus for red oak). Hot leach is faster — boil in changes of water — but sets the starch so you can’t make crisp flour after. Dry the leached meal and grind into acorn flour for breads and pancakes.

Notes

White-oak-group acorns are the beginner’s choice — sweeter, faster to leach. Don’t shortcut the leaching; unleached acorns taste terrible and upset the gut.