autolysis: one construct, many systems

When yeast cells die and rest on their sediment, their own enzymes break down the cell contents and release amino acids, fatty acids, and nucleotides back into the beer or wine: autolysis. In packaged beer it is a defect, giving meaty, rubbery off-flavours, yet winemakers exploit the very same process in sur-lie and sparkling-wine ageing to build savoury complexity. Boulton and Quain's Brewing yeast and fermentation and Alexandre and Guilloux-Benatier's review of Yeast autolysis in sparkling wine describe the enzymes and the compounds released. The referent is a cell digesting itself with its own hydrolases after death, the same event a pathologist reads in a body.[1][2]

Unit

The amount of cell material released into the liquid over time

Recovery means

Not applicable

Measured by

Tracked by released amino nitrogen, nucleotides, and the onset of autolytic off-flavours

In pathology autolysis is the self-digestion of tissues after death: deprived of oxygen, cells can no longer maintain themselves and their own lysosomal and cytoplasmic enzymes dissolve cell structures from within, before bacterial putrefaction takes over. DiMaio and DiMaio's Forensic pathology treats autolysis among the early post-mortem changes used to read the state of a body. It is the same enzymatic self-digestion construct as in spent brewing or wine yeast, here in the tissues of a dead organism rather than a fermentation vessel.[3]

Unit

The extent of tissue breakdown after death

Recovery means

Not applicable

Measured by

Assessed by histological breakdown, organ softening, and its contribution to estimating the post-mortem interval