- Acetaldehyde is an intermediate product of yeast fermentation.
Some residual acetaldehyde is to be expected after fermentation.
The residual amount depends predominantly on yeast strain and to a lesser extent on fermentation conditions
- Acetaldehyde is also produced on the oxidation of alcohol in wine
- Acetaldehyde can also be introduced through fortification, from the fortifying spirit.
- Acetaldehyde is strongly bound to sulphur dioxide (SO2) with important implications for wine production.
- Acetaldehyde at low concentrations, can add to flavour complexity in full flavoured wines, especially red wines.
- High concentrations of acetaldehyde can leave the wine tasting flat with flor sherry characteristics.
- Other descriptors for acetaldehyde are green apple, sour and metallic.
- Acetaldehyde is a two (2) carbon aldehyde with the chemical formula C2H6O and structure as per this diagram
It is the end carbon (C) with the double bonded oxygen (O) and single bonded hydrogen that forms the aldehyde functional group.
- Other aldehydes are also produced by yeast in smaller quantities, but with significant flavour contributions.