Lye

Lye a term now used in N. America to denote a dilute solution of caustic soda. In earlier centuries it meant an impure solution mostly of caustic potash, made by boiling wood ash in water. This was of considerable importance, since it and lime were the only alkalis available for tasks such as making soap. The culinary uses of lye (of either kind) include removing the bitterness from green olives and preparing the remarkable preserved fish known in Scandinavia as lutefisk.