Borras
From Eating Asturias, the Encyclopedia of Asturian Gastronomy
Las borras is the Spanish term for the lees or trub left from cider making. In Asturias, this is commonly referred to as la madre.
Like the lees of wine making or the trub of beer making, it is comprised of the vegetable material and other insoluble material in the cider during fermentation. Racking (trasegar in Spanish) is the process of moving the liquid off of las borras into a new vessel.
