The truth behind red wine and egg whites

Most of us expect that when we pour a glass of wine it will be clear and bright. But did you know that egg whites can be partly responsible for this clarity we have come accustomed to? This is because when wine finishes fermenting there are still suspended particles of dead yeast cells, fragments of grape pulp, skins and stems, tartrates and colloids (tannins, proteins and phenolic particles) floating throughout the liquid.

Most wines, if left long enough, will self-clarify with the help of gravity pulling the particles to the bottom of the wine barrel, which can then be siphoned off before the bottling process begins.

However, in the interest of efficiency and in getting the wine to market in a timely manner, some winemakers help the process along by using a variety of aids, such as fining agents, to help clarify the wine and render it free of suspended particles.

According to Wine Maker Magazine, egg whites are one such fining agent as they are rich in albumen, making them ideal for softening a wine’s astringency by binding and reducing the tannin content (leftover from grape skins, seeds and stems). Depending on the size of the egg, between three and eight egg whites are used within a 225 liter barrel of red wine. After a short wait, the egg white and free proteins precipitate out of the wine and drop to the bottom of the barrel. Winemakers can then strain the clear wine off the top and move it to another container, leaving the egg whites and other unwanted particles behind.

That being said, while most of the egg white is gone before the bottling process begins, those with a severe egg allergy or otherwise adverse to consuming eggs, could still potentially be affected. Using Neogen’s Veratox® for Egg allergen test kit, detection of as little as 2.5 parts per million of egg white is possible, and is one way winemakers could determine if there is still egg white remaining in their wine.

With all these egg whites, you are probably left wondering: What about the egg yolks? Interestingly, in areas where red wine is produced, products made with egg yolks, such as desserts or cakes, are also very popular. For example, Bordeaux, in southwestern France, was made popular for their red wine blend that holds the same name, and is made exclusively in the city. Here, you will also find 'canelés' (small pastries with a soft custard center and a dark, thick caramelized crust) everywhere, in which egg yolks are a main ingredient. Now you know.