the Glossary of Wine Preservatives and Additives

Alcohol – a natural by-product of yeast fermentation converting sugar to ethanol and carbon dioxide. Alcohol may cause allergic reactions in some people, regardless of the level of preservatives, tannins or esters in the wine. (Of course, alcohol is also responsible for hangovers, but these can be easily avoided by simply drinking in moderation!) Extra alcohol may not be added to wine at any stage of the winemaking process.

Sulphur dioxide – labelled "Preservative 220" or "SO2", this is the most contentious and maligned of wine additives. It has been used for thousands of years in wine production. A small amount of SO2 is produced naturally as part of the fermentation process in all wines.

Ascorbic acid – also labelled "Antioxidant 300" and commonly known as vitamin C, ascorbic acid is naturally present in grapes. In Australia winemakers can add ascorbic acid to white wines to help prevent oxidisation. Ascorbic acid is not used in red wines. When added to fruit juices it is listed as "Vitamin C".

Chaptalisation – sometimes called ‘enrichment’, the addition of sugar to a wine raises the alcohol level, enhancing a wine’s flavour and body. In Australia, sugar can only be added in the form of concentrated grape must (grape juice). Addition of sugar (sucrose) is common in Northern Europe, parts of the USA, Canada, Brazil, Japan and much of New Zealand.

Acidification – In much the same way that chaptalisation is used to lift highly acidic wines from cooler regions, acid is used to balance the sweeter, ripe flavours of wines from warm to hot regions. It may be added in the form of tartaric, citric or malic acid and helps brighten the colour of wine while freshening flavours and aromas.