The third test strip was again baited at 37 C. After 3 hours of baiting the test strip was removed from the pepsin solution. The hide was now extremely thin, delicate, and translucent. This test strip was then cut in two pieces. One half will be alum paste tanned and the other half will be alum solution tanned.
Pickling
Both halves of the third test strip were introduced to a solution of distilled water and acetic acid. This solution had a pH of 4. This process lowers the pH of the hide in preparation for the acidic tanning process.
Vegetable Tanning.
Although we had originally intended to gradually increase the concentration of the tanning solution to which the second test strip was exposed; the speed at which the test strip absorbed tannins from the solution was more rapid than we had expected. Therefore, we decided to keep the concentration of the tanning solution the same throughout the entire tanning process. I created a new tanning solution of the same concentration by combining 300 mL of distilled water with 100 mL of quercitannic acid solution extracted from oak bark. The second test strip was added to the new vegetable tanning solution and left to sit.
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