Parchment
Skinning, soaking, and dehairing

After a carcass is skinned, the hide is soaked in water for about a day. This removes blood and grime and prepares the skin for a dehairing liquor. The dehairing liquor was originally made of rotted, or fermented, vegetable matter, like beer or other liquors, but by the Middle Ages a dehairing bath included lime. Today, the lime solution is occasionally sharpened by the use of sodium sulfide. The liquor bath would have been in wooden or stone vats and the hides stirred with a long wooden pole to avoid human contact with the alkaline solution. Sometimes the skins would stay in the dehairing bath for eight or more days depending how concentrated and how warm the solution was kept – dehairing could take up to twice as long in winter. The vat was stirred two or three times a day to ensure the solution's deep and uniform penetration. Replacing the lime water bath also sped the process up. However, if the skins were soaked in the liquor too long, they would be weakened and not able to stand the stretching required for parchment.
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