Why does my wine contain milk products?

This unusual question was posed recently by a customer who was rather surprised to find the following label on the back of her Chardonnay - 'This wine has been produced with aid of milk products and traces may remain' thus leading to the perplexing question of what milk was doing in a bottle of wine.

For the answer to this we can look back to 2002, when the Food Standards Authority (FSANZ) revised the food standard for Australia and New Zealand. Within this revision, wine was more formally recognised as a food, thus subjecting wine to the same (world class) standards of health and safety as 'food products'.

Also in the revision was a change in food labelling, including the advent of the allergen warning - a declaration requiring producers to specify if certain substances have been used as an ingredient, food additive or processing aid and are present in the final product. These substances have been identified as allergens - substances that can cause an adverse allergic reaction in humans. They include:

- Cereals containing gluten and their products
- Crustacea and their products
- Egg and egg products
- Fish and fish products
- Milk and milk products
- Nuts and sesame seeds and their products
- Peanuts and soybeans, and their products
- Added sulphites in concentrations of 10mg/kg or more
- Royal jelly
- Bee pollen
- Propolis

Now wine is a classically natural product (fermented grape juice) with stringent laws on what can be 'added' to wine, yet there are some quite unusual natural products that are used in the production process. Previously, little attention was paid to these products, however the increased awareness of allergens and the increased prevalence of allergies ultimately spurred the food standards authority to introduce the requirement for the allergen warning.

Some products used by winemakers include several foods (listed above) which are recognised as common allergens, including milk, eggs and fish, all of which are used as fining and clarifying agents (leading to brighter, cleaner wines). Egg whites, for example, are sometimes added to red wines to remove astringent tannins. The protein in the egg whites bind to the tannins, which then polymerise and form a deposit in the bottom of the barrel. Before bottling, the wine undergoes a process of racking, whereby the wine is seperated from the solid sediments, leaving the egg white deposit behind in the barrel (thus little, if any, actual egg white actually makes it way into the final wine - particularly after the wine passes through standard filtration).

Some of the other substances used by winemakers include casein, a protein derived from milk (which is used for clarification), or Isinglass, which is derived from fish swim bladders. Some winemakers also add tannin to red wine to give it more 'body' and the tannin can occasionally be derived from chestnuts.

The reality is that most of these products are used largely as production aids and the additions are so minimal, with such low concentration in the final product, that they are viewed as essentially innocuous. A study funded by the Australian government wine & grape research body (GWRDC) found that negligible levels of allergens remain in finished wines, and as yet there has been no medical evidence to support any linkage between wine fined with egg, fish or milk products and allergic reactions.

So next time you spot a wine 'produced with the aid of fish products' think allergies and not seafood
Andrew Graham