Tannic Acid: Chinese Galls Extracted with Warm Water, Shaken with Ether and Dried on Tin Sheets

This is the large-scale way to make commercial tannin, as Thorpe's Dictionary (1913) gives it. Chinese galls from sumach hold as much as 70 % tannin; the best oak galls, from Aleppo, 50–60 %. The powder is extracted with warm water, and the extract is shaken with ether. After several days the ether layer on top is taken off; the tannin stays in the lower layer, which is dried on hot tin sheets until it puffs up. The product still holds some gallic acid, wax and glucose. Ether is very flammable: no flame. The picture: our diagram.