The mash left after brewing rice wine, used as a seasoning for its winey taste. Fujian's 红糟, the lees of wine brewed with red yeast rice, is red and slightly sour and flavours chicken, pork and eel.
The leftover distiller's grains from brewing are often used as animal feed.
Tips
culture
酒糟 used in cooking is the lees left from making rice wine (黄酒 or 米酒). It flavors and cures fish and meat (酒糟鱼, 糟溜鱼片). The grains left after distilling baijiu mostly go to livestock feed. 糟 alone can mean 'dregs' or 'spoiled'.