by Dave Salaba
Many of our customers hesitate to use sulfites in their wine because they have heard negative things. They’ve heard that sulfites in wine, particularly red wine, can cause headaches and allergic reactions. Here’s an article from Brew King’s newsletter, The Vine that sets the record straight.
Sulfites are present in both wine made from kits and in commercial bottled wines. In wine kits, they take the form of metabisulphite. Home winemaking also dictates the use of a sulfite solution to sanitize equipment and bottles. And that’s not a bad thing. In fact, it’s essentially harmless, even necessary. Potassium metabisulphite is a source of sulfur dioxide, which inhibits yeast, mold and bacteria. It does this in two ways: it kills or stuns some of the organisms, and it blocks the ability of the surviving organisms to reproduce. Both of these come into play at the end of the fermentation process, stopping fermentation activity and protecting the wine. The reproduction-blocking action is also what makes sulfite effective as a sanitizing agent–if your winemaking equipment is physically clean and you’ve rinsed it with a sulfite solution, nothing will grow on it.
Sulfites are also added directly to wine after fermentation, to help prevent oxidation. Oxidation in wine follows the same pattern that you see when you cut open an apple and expose it to air–the wine turns brown and takes on a flat, “cardboard” taste. Sulfur binds with the oxygen in the wine and prevents this damage.
The use of sulfur compounds is not new to wine-making. The Dutch popularized the use of sulfur to treat wine in the 16th century by refusing to ship any wines not treated, insisting that wines treated with sulfur were the only ones that could survive a long sea voyage without turning into vinegar.
Some people worry that they may be allergic to sulfites. True sulfite allergies are very rare. It’s more likely that they have had a histamine reaction to red wine. What most people describe as a sulfite headache is a reaction to bio-amines, compounds formed in wines for various reasons, one of which is malolactic fermentation (the addition of special bacteria for a secondary fermentation) in the presence of sugar. Some wineries start malolactic inoculation before the end of alcohol fermentation, guaranteeing formation of bio-amines. Since wine kits don’t go through malolactic treatment, they do not form bio-amines and consequently do not provoke allergic reactions.
* Some facts about sulfites:
- Sulfites are a recognized food additive. The federal government controls their use.
- All commercial wines contain sulfites, even those labeled “Kosher” or “Organic”!
- Many dried fruits and meats contain sulfites. For example, raisins have up to 250 PPM. Food products such as bacon, orange juice, potato chips, candied fruits, sausages and even pancake syrup contain sulfite–many at levels higher than wines.
- All grape-based wines produce sulfite naturally during fermentation, up to a level of about 10 PPM. Even with no sulfite additions, wine still contains them.
- The human body produces sulfite as a by-product of its metabolic activity. The sulfite is excreted through the kidneys.
This is not to say that sulfites are totally benign. People with breathing problems should avoid inhaling sulfite powder or the gas that comes off the prepared solution. It can act as an irritant, aggravating any breathing problems. Also, adding too much extra sulfite to wine is of no benefit, as it can spoil the flavor, giving it a “burnt match” smell. It’s important to follow directions for sulfite additions.
The upshot of sulfite use is that without them, you’d have to be very careful to keep all of your equipment sanitary (with chlorine- or iodine-based sanitizers) and you’d have to drink your wine quickly, before it spoiled, probably within 1 or 2 months. The legal sulfite limit in commercial bottled dry table wines is 70 PPM. The amount of sulfite provided in Brew King wine kits will result in a level of between 16 and 25 PPM in a finished wine. Our instructions specifically allow for the option of adding sulfites in should you wish to age your wines for an extended time, giving you some degree of flexibility in the amount of sulfites present.
Keystone Homebrew Supply recommends the use of sulfites in all homemade wines. Adding sulfites to your wine is easy. A good rule of thumb is to add ¼ teaspoon per 5-6 gallons each time you: first start your wine (not in kit wines because they already contain your initial dose), rack/transfer it (wine kits provide this dose), and bottle the wine (the sulfites are not included in wine kits). Sulfites have a limited shelf life and we recommend using fresh sulfite crystals (under $2 per 2 oz.) each year. A more detailed discussion on sulfites can be found on Winemaker Magazine’s website.