http://en.wikipedia.org/wiki/Dotorimuk
Despite being a rich source of starch and proteins, acorns contain large amounts of tannins and other polyphenols, which prevent the human body from digesting food properly. As such, the harvested acorns must be properly leached of the tannins prior to consumption. Acorns are either collected directly from the ground or knocked off the branches of trees. The harvested acorns are then opened and their nuts inside ground into a fine orange-brown paste. The paste is then stirred into vats of water such that the fibre in the acorn can be separated from the starch through sieving and settling.
The starch suspending liquid is collected from the fibre and allowed to sit so that the tannins in the starch will diffuse out of the acorn paste. The soaking time depends on the amount of tannins in the paste, but the process usually requires several changes of water to properly purge it of all noxious substances.
The now tannin-free acorn starch paste should have an off-white colour. This paste is allowed to completely settle to the bottom of the vat. The water is drained away, and the paste is then collected in trays to dry. The dried starch cake is then pulverized and packaged for sale. Dotorimuk is also commercially available in powdered form, which must be mixed with water, boiled until pudding-like in consistency, then poured into a flat dish to set.
If there is a Korean grocery store near you, you can probably find the ground up acorn powder! A lot easier than grinding acorns up yourself if you want ground
acorns for whatever project you are working on, whether its to make mook or some other dish that utilizes the acorns.
