Clarification and stabilization of wine Organic compounds used as fining agents are generally animal based, a possible cause of concern to vegans. The most common organic compounds used include egg whites, casein derived from milk, gelatin and isinglass obtained from the bladders of fish. Pulverized minerals and solid materials can also be used, with bentonite clay being one of the most common, thanks to its effectiveness in absorbing proteins and some bacteria. Activated carbon from charcoal is used to remove some phenols that contribute to browning as well as some particles that produce "off-odors" in the wine. In a process known as blue fining, potassium
Yeast in winemaking and amino acids or YAN) but also minerals (such as magnesium) and vitamins (such as thiamin and riboflavin) that serve as important growth and survival factors. Among the other nutritional needs of wine yeast: Many of these nutrients are available in the must and skins of the grapes themselves but sometimes are supplemented by winemakers with additions such as diammonium phosphate (DAP), freeze-dried micro-nutrients (such as "Go-Ferm" and "Ferm-K") and even the remnant of dead or extracted yeast cells such that the fermenting yeast can break down to mine for available nitrogen and nutrients. One historical winemaking tradition that is