Fault
Yeast autolysis
Dead yeast breaking down and releasing rubbery, meaty compounds — the result of leaving beer too long on a yeast bed.
Also called yeast bite, meaty, rubbery.
What it tastes and smells like
If you are drinking it
A rubbery or meaty note is a brewing fault and cannot be fixed. It is harmless.
Not a safety issue. Beer’s alcohol, hop compounds and low pH make it inhospitable to organisms that cause illness.
What causes it
| Cause | Stage | How often | Who can act |
|---|---|---|---|
| Beer left on a thick yeast bed for weeks, particularly warm and under pressure at the base of a tall vessel. | conditioning | most common | brewer |
If you are brewing it
- Brewer: Rack off the yeast bed within a reasonable time, or dump trub from conical fermenters during conditioning. (prevents)
Where in the process this comes from
Steps that can produce this fault when they go wrong. Each links to what the step is for and how it is controlled.
- Lagering — Store beer cold for an extended period after fermentation to clarify it and produce the clean, rounded character lagers are named for.
- Yeast harvesting — Collect yeast from a finished fermentation and pitch it into the next batch, generation after generation.
Often confused with
- Excess sulphur — rotten egg, struck match
- Lightstrike — skunk, burnt rubber
Evidence
What BeerHQ knows about this, and how. Every statement carries the state of the evidence behind it rather than being presented flatly as fact.
Yeast cells left too long on a thick sediment break down and release their contents, producing rubbery and savoury off-flavours distinct from the bready character of healthy yeast in suspension.
Backed by a source
Sources: Yeast: The Practical Guide to Beer Fermentation — print; Beer: Tap into the Art and Science of Brewing — print