Acorn Tannnase

Gallic acid / Health Benefits

Tannins in oak break down into gallic acid and ellagic acid which both are know to have anti-oxidant properties and health benefits.

500 grams Freshly Dried White Oak (finely powdered)
750 grams Toasted White Oak (finely powdered)
200 grams Acorn Kernels (finely ground)
2000 ml of 0.70% Magnesium Chloride Solution (approximate*)

  • The amount of magnesium chloride solution used should be enough to moisten the wood-acorn mixture enough that it is wet but no excess liquid.
  • The magnesium chloride is used as an antiseptic/antimicrobial to inhibit fermentation or spoilage of the oak mixture before the beneficial growth of Penicillium.

One pound of comminuted white oak, untoasted, is mixed with one pound of the wood lightly toasted, or two pounds of lightly toasted
wood may be employed. To this is added 10% to 20% by weight of acorn kernels ground to an impalpable powder; the kernels employed may
be fresh or they may be kernels that have been preserved in alcohol. The toasted and untoasted wood, together with the acorn powder, is thor
oughly mixed, and to this is added about four pounds of magnesium chloride solution 1 to 150, The entire batch is again mixed and placed in
a suitable covered container (such as charred Oak wood, glass, enamelled metal or the like), which is only partially filled. It is best placed in a room
maintained at a temperature from 75° to 85 C. for a period of from five to ten days, and it should be mixed each day or so to maintain the wood at
a uniform moisture. If there is any tendency to dry out, additional magnesium chloride in solution specified should be added.

In from five to ten days, depending on the temperature, the growth will be fully developed, and the enzyme liberated by the growth should have completely dissociated the tannins contained in the oak wood. A suitable test to determine whether this stage of the incubation period has been completed is as follows:
Each day, beginning with the fourth day, a small sample of the processed wood is macerated for twelve hours with about three or four times
its bulk volume of 100 proof white whisky and tested for complete tannin conversion. When three drops of a 1% aqueous solution of ferric
chloride are added to 3 cc. of this extract, no blue color or precipitate should be produced, but a clear olive green or amber color should result, showing that the extract is free of gallic acid. If the test proves that the tannic and gallic acids of the wood have been fully converted, then it is ready for further treatment.

At this time one pound of comminuted white oak, toasted to a light golden brown color, is added, and an additional two pounds of a solution 1 to 150 of magnesium chloride. The whole batch is again mixed and placed in the container and allowed to remain therein for a period of from ten to twenty days, depending upon the temperature of the room. During this period Penicillia, alone should be developed, as the toasting operation has destroyed most of the remaining fungi. When the Penicillia has reached a prolific growth, a fruit mustard-like odor is developed. The tannins of the added
wood will become fully dissociated, and the batch as a whole is ready to be mixed with the white whisky, Wine, or liquor to be aged.

Each ounce of the processed wood will treat sixteen times this amount of white whisky. In other words, 500 grams of the moist processed wood will treat approximately 8 litres of distillate. For fortified wines, only about half the amount of processed wood is required.

Treat this like a sour dough starter and only use half at a time and then replenish the toasted oak and acorn mixture. Fresh white oak is not needed afterwards because the spores have been captured already. The penicillin fungi will feed on the acorn and break down tannins as long as the “Pappy” is cared for.

Additional Information

Tannase in Beer