What substance was used to soften tanned hides during the tanning process?

• A. Soap.
• B. Water only.
• C. Deer brain.
• D. Salt.

Answer: (C)

Softening leather after tanning comes from conditioning the collagen fibers with fats and oils. In traditional brain tanning, the fats and emulsifiers found in the animal’s brain are worked into the hide. Those brain oils coat and lubricate the fibrous structure, reducing stiffness and making the leather pliable. That’s why deer brain is used—its natural fats are specifically suited to soften and condition the hide. Other substances don’t provide that conditioning effect: soap cleans and can strip oils, water alone doesn’t soften, and salt dries and stiffens the material.