In brewing

Brewing

Brewing is the production of beer through steeping a starch source in water and then fermenting with yeast. Brewing has taken place since around the 6th millennium BCE, and archeological evidence suggests that this technique was used in ancient Egypt...

, free amino nitrogen (FAN) is a measure of the concentration of individual wort

Wort (brewing)

Wort, , is the liquid extracted from the mashing process during the brewing of beer or whisky. Wort contains the sugars that will be fermented by the brewing yeast to produce alcohol.- Production :...

 amino acids and small peptides (one to three units) which can be utilised by yeast

Yeast

Yeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with 1,500 species currently described estimated to be only 1% of all fungal species. Most reproduce asexually by mitosis, and many do so by an asymmetric division process called budding...

 for cell growth and proliferation. For vigorous fermentation, a sufficient quantity of FAN must be present in the wort

Wort (brewing)

Wort, , is the liquid extracted from the mashing process during the brewing of beer or whisky. Wort contains the sugars that will be fermented by the brewing yeast to produce alcohol.- Production :...

. An excessive concentration in the wort

Wort (brewing)

Wort, , is the liquid extracted from the mashing process during the brewing of beer or whisky. Wort contains the sugars that will be fermented by the brewing yeast to produce alcohol.- Production :...

 is not desirable however, as this may cause production of a significant quantity of fusel alcohols, or spoilage of the finished beer

Beer

Beer is the world's most widely consumed andprobably oldest alcoholic beverage; it is the third most popular drink overall, after water and tea. It is produced by the brewing and fermentation of sugars, mainly derived from malted cereal grains, most commonly malted barley and malted wheat...

by other organisms.