Oak

Oak
Foliage and acorns of Quercus robur
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Fagales
Family:	Fagaceae
Genus:	Quercus L.
Species
See List of Quercus species

The main edible product of oak trees is their dry fruits, acorns. Acorns contain bitter and toxic tannins which must be leached out in water before the acorn is considered edible.

In February 2018, acorns of the coast live oak (Quercus agrifolia) were gathered from hillsides near Avila Beach, CA.

This process was used to leach and grind the acorns:

• Acorns were shelled and any with acorn worm holes or dark colored rot were discarded. The yield of good acorns was near 50%.
• Acorn meats were chopped into 1-2mm fragments with a mechanical hand chopper (think "Slap Chop"). They were not yet ground finely because as coarse fragments it is possible to rinse them using a mesh strainer.
• The fragments were soaked in cold water which was changed 1-2x daily for about a month. Over this course of time the bitterness and astringency were observed to diminish by tasting samples.
• The fragments were dried overnight in an oven on the dehydrator setting (130 degrees Fahrenheit).
• The dried fragments were ground into a flour in an electric coffee/spice grinder.

This produced a chocolate brown flour, not as fine as pastry flour but fairly fine thanks to the electric grinder.

Recipes using the flour:

• Combine with boiling water and a pinch of salt to make acorn mush/porridge.
• Combine with a sweetener (honey) and a solid fat and bake to make acorn lace cookies. We did not get the proportions quite right on this one, since the cookies fell apart.

Acknowledgements

This article uses material from the Wikipedia article Oak, which is released under the Creative Commons Attribution-Share-Alike License 3.0.