The fermentation process is actually a yeast metabolism […]
The fermentation process is actually a yeast metabolism process. To obtain high-quality beer, you must first have a yeast strain with vigorous vitality, strong itself, good performance, and beneficial flavor. The performance of yeast changes due to factors such as fermentation process conditions and appearance environment. Yeast senescence, death and autolysis will inevitably occur. How to reduce yeast autolysis and prolong the service life of yeast is the fundamental basis for ensuring stable beer quality.
Causes of yeast autolysis
The cytosol of yeast cells contains more intracellular proteolytic enzymes. Under normal process conditions, the yeast is strong and the yeast intracellular proteolytic enzymes will not leak out. When the process environment deteriorates and the yeast ages or dies, the intracellular proteolytic enzymes will leak out, and act on the protein structure of the yeast cell wall, causing the yeast cells to rupture, and yeast autolysis will occur, commonly known as "yeast internal consumption". . After yeast autolysis, some substances in the cytoplasmic solution, such as polysaccharides, amino acids, proteins, peptides, nucleotides, and a little salt, enter the beer in large quantities, causing the total nitrogen, ɑ-amino nitrogen, ph value, conductivity and other indicators in the beer to occur. Changes have an impact on the flavor and colloidal stability of beer.
Yeast autolysis is inevitable during beer fermentation, but the degree of autolysis and the speed of autolysis are different. Our goal is not to prevent yeast autolysis, but to control the degree of yeast autolysis and delay the process of yeast senescence and death.