Wine Analysis Home
- Oxidation of wine involves the bonding of of oxygen molecules to oxidisable compounds present in wine.
- Wine oxidation occurs much more slowly then juice oxidation, but will occur over time when in contact with oxygen.
- Oxygen can be introduced into wine through partially filled storage vessels, leaks and transfers.
- Oxidation of wine results in -
- The production of brown compounds and browning of red piments with loss of colour.
- The destruction of both desirable grape (primary), fermentation (secondary) and aging (tertiary) derived flavours.
- The production of new undesirable flavour compounds which can mask the desirable flavour compounds. These include different compounds to those produced in the oxidation of juice.
Wine oxidation minimization -
- Oxidation is reduced in the presence of sulphur dioxide (SO2), hence judicious and calculated additions.
- Oxidation is reduced in the combined presence of ascorbic acid and FSO2 (free sulphur dioxide).
The use of ascorbic acid in conjuction with Sulphur dioxide should be used in white wines only where free sulphur dioxide (FSO2) can be guaranteed. See ascorbic acid use in red wines.
- Preventing contact of oxygen through leaks in tanks, barrels, pumps etc
- Minimise wine handling (e.g. plan logistics to minimise rackings)
- Avoiding metal contamination. (see catalysts in wine chemistry)
- Storage at reduced temperatures.
- The overriding element in wine oxidation is the amount of oxygen present and time exposed.
- The slow, insidous oxidation of wine means that the effects are not noticed until the damage is done.