If you look at the back label on a bottle of wine, you'll see a list of additives.

The two most common additives are often shown as the numbers 220 or sulphur dioxide and 300 or ascorbic acid. 220 is a commonly used preservative that's also in dried fruit and juice, and 300 is the antioxidant we usually know as our old friend vitamin C.

Although these preservatives are added to your wine in very small concentrations - only a few parts per million, they play a crucial role in keeping the wine fresh. If the winemaker doesn't use them the wine quickly reacts with oxygen, goes brown and tastes pretty awful.

Winemakers now need to declare the use of processing aids on their labels. You may have noticed phrases like 'contains milk products' or 'egg fining agents used and traces may remain'. Winemakers have used eggwhites and skim milk for centuries to clarify wine - 'fining' is another word for clarifying.

Another less common declaration is 'contains nuts'. This has come about because of the use of added tannin, a widespread and perfectly legal practice in Australia employed to stabilise the colour and beef up the 'mouthfeel' of red wines. Much or the tannin used by winemakers is extracted from grapes, but some tannin is taken from galls found on the bark of the chestnut tree, And although most scientists believe it is not strictly speaking, a 'nut product' but a 'tree product', winemakers think it's better to be safe than sorry as nut allergies can be life-threatening.

Similarly, although most winemakers believe that no traces of any of the clarifying agents or processing aids remain in the wine as it is filtered before bottling they can't be 110% certain, so these allergens are clearly stated on the label.

If you are worried about additives, go for preservative-free wine. But you'll need to drink it as soon as possible after it's released because .... there's no preservative!

Source:Better Homes and Gardens May 2004