Do I need to use preservatives in my wine?
Preservatives (sulfites) are an important part of wine making. Don’t worry about adding them to your home-made wine. Not only do they keep wine from developing infections, they also keep the wine from oxidizing. If you are concerned about the use of sulfites in wine read on!
The preservative we most often recommend is sulfite, since it occurs naturally in small amounts during fermentation. Sulfites are your friend. Not only do they keep wine from developing infections like film yeast, mold, and acetobacteria (vinegar bacteria), they also keep the wine from oxidizing. Without the use of sulfites you have to be terrifically careful to keep all of your equipment very sanitary and you still have to drink your wine up as quickly as possible before it spoils.
Many people worry that they may be allergic to sulfites. True sulfite allergies are very rare. It’s more likely that they have been exposed to a high level of sulfites in the past. In the 1970’s restaurants would douse their salad bars with 2000 PPM (part per million) sulfite solutions in order to keep the produce fresh. Mixing this with acidic foods, such as salad dressings or vinegar, would cause the salad to release clouds of sulfite gas, provoking unpleasant reactions.
What most people describe as a sulfite headache is a reaction to bio-amines. These are compounds formed in wines for various reasons, one of the most common being malolactic fermentation in the presence of sugar. Some commercial wineries start malolactic inoculation before the end of alcohol fermentation, guaranteeing the formation of bio-amines. Since most wine kits don’t go through malolactic fermentation, they do not form bio-amines, and consequently don’t provoke allergic reactions.
Potassium Metabisulphite is also a stable source of sulfite in winemaking. The use of sulfur compounds is not a recent innovation. The Dutch shipping companies popularized the use of sulfur in the 16th century by refusing to ship any wines not treated. They insisted on the use of sulfites because the treated wines were the only ones that survived a long sea voyage without spoiling.
Sulfites work by releasing free sulfur dioxide, which inhibits yeast, mold and bacteria. It does this in two ways: one, it kills some of the organisms outright, and two, it blocks the surviving organisms’ ability to reproduce. If your winemaking equipment is physically clean and you’ve rinsed it with a sulfite solution, nothing will grow on it.