Beer fermentation mechanism

The beer fermentation process is the process in which yeast metabolizes the fermentable sugars in the wort after saccharification under anaerobic conditions, allowing us to finally obtain delicious beer.

Respiration and fermentation

Yeast can both aerobic respiration and anaerobic metabolism, it is a facultative microorganism. The process in which yeast consumes fermentable sugars to produce water and carbon dioxide and releases more energy under aerobic conditions is called aerobic respiration; under anaerobic conditions, the process of decomposing fermentable sugars to produce alcohol and carbon dioxide and release energy is called fermentation .

When the cold wort enters the fermenter, the yeast needs to multiply rapidly and consume a lot of energy, so it is necessary to provide enough dissolved oxygen to the yeast before the fermentation starts, so that the yeast cells can obtain enough energy for reproduction; stage, and then transferred to the anaerobic fermentation stage.

For brewer's yeast, the main source of carbohydrate supply is low molecular sugar, which yeast can use for metabolism such as monosaccharide, disaccharide and trisaccharide; while high molecular polysaccharide such as starch, cellulose, etc., cannot Used by yeast. Do you know which sugars can be used by yeast? This is very important for beer brewing, fermentability is divided into:

Monosaccharides: glucose, fructose

Disaccharides: maltose, sucrose

Trisaccharides: Maltotriose (not available to all yeasts).

Under aerobic conditions, yeast undergo aerobic respiration, the process of yeast reproduction, sugar is broken down into water and carbon dioxide, and energy is released. Its reaction formula is:

C6H12O6 (glucose) + 6O2 (oxygen) + 6H2O → 6CO2 + 12H2O + ATP (a lot of energy) (aerobic respiration)

Under anaerobic conditions, yeast performs anaerobic fermentation, the beer fermentation process, in which sugar is fermented, ethanol and carbon dioxide are produced, and energy is released. Its reaction formula is:

C6H12O6 (glucose) → 2C2H5OH+2CO2+ATP (energy) (anaerobic respiration)

The biochemical mechanism of alcohol fermentation of glucose is the most basic theory of alcohol production and wine brewing. For beer brewing, in addition to the fermentation metabolites alcohol and CO2, which are the main components of beer, the EMP pathway in the metabolic process is also the basis for the formation of many metabolites, so being familiar with this process is also very important for the study of other beer flavor components.

Stainless steel tank fermneters stackable