faecula
From LSJ
faecŭla: (also fēcŭla, and contracted faecla, Cael. Aur. Tard. 2, 1), ae, f.
dim. id.,
I burnt tartar or salt of tartar, deposited in the form of a crust by wine (used as a condiment or as a drug), Lucr. 2, 430; Hor. S. 2, 8, 9; Scrib. Comp. 226 al.