How to Stop Yeast Autolysis

Autolyzed yeast might be desirable in process foods but autolysis can spoil your home brew.

Autolysis refers to the process of self-digestion of the body content of a cell bit's own enzymes. As a yeast cell dies, it ruptures releasing amino acids, riboflavin, organic and inorganic phosphorus compounds such as nucleotides, which can taste like sulfur and rubber. The end product of autolysis is yeast extract, which is used in many processed foods to enhance flavors. In beer, mead or wine making, however, autolysis is undesirable as it creates an "off" flavor.

Instructions

1. Turn the temperature up. High temperatures will slow yeast metabolism and a temperature of above 100 degrees Fahrenheit will cause yeast to die, inhibiting autolysis.

2. Low temperatures will inhibit yeast autolysis. Maintaining a mixture that contains yeast at a temperature of 45 to 55 degrees Fahrenheit will inhibit yeast autolysis.

3. Decrease the yeast mass. If you have large amount of yeast at the bottom of the fermenter, autolysis risk is increased. Prevent autolysis by moving your mixture to a secondary fermenter.

4. Aerate your wort, the liquid extracted during the beer or mead making process, in order to avoid autolysis. This can be achieved by covering your container and agitating it by rocking the container back and forth.

References

• Drayman's Brewery and Distillery; Yeast Autolysis; Mark Kallmeyer; 2005
• Acumedia: Yeast Extract
• Bacchus and Barley; Yeast Autolysis; Yeast Autolysis; 2009
• How to Brew; Chapter 10 - What is Different for Brewing Lager Beer; John Palmer
• Wine Maker Magazine; Preventing Off-Flavors; Sunshine Gladish; 1998
• The How-To Homebrew Beer Magazine; Preventing Yeast Off-flavors: Tips from the Pros; 2007

Resources

• The How-To Homebrew Beer Magazine; Aerating wort: Techniques; John Sitka; 2009