Info on Sulphites

In the past, we have had several customers who are concerned about the use of sulphites in our winemaking process.  In an attempt to clear up any misunderstandings, here are a few facts about sulphites that you should know.

Potassium Metabisulphite is a stable source of sulfites in winemaking.  Sulphites 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.

To help prevent oxidation, sulphites are also added directly to wine after fermentation.  Wine oxidation follows the same pattern that you see in the cut edge of an apple – the wine turns brown and takes on a flat cardboard taste.  Sulfur binds with the oxygen in wine and prevents this damage.

Many people worry that they may be allergic to sulphites in wine.  True sulphite allergies are very rare.  It’s very likely that most people have been exposed to much higher levels of sulphites in the past.  In the 1970’s for example, restaurants would douse their salad bars with 2000 PPM (parts per million) sulphite solution 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 sulphite gas, provoking unpleasant reactions.

What most people describe as a wine headache or a sulphite headache is actually a reaction to bio-amines in the wine.  Bio-amines are compounds formed in wines for various reasons, one of the most common being malolactic fermentation in the presence of sugar.  In this process, malolactic bacteria is added to (primarily) red wines to soften the wine by converting the harsher Malic acid into the more mellow tasting Lactic acid (like in yogurt).  This makes the wines drinkable at a much younger age.  The large amounts of bio-amines produced by this process provoke the allergic reactions some people have to red wines and some whites such as malolactic-affected  Chardonnays.  Wines made from wine kits never go through malolactic fermentation and thus will not give headaches to those who respond negatively to malolactic commercial wines.

This is not to say that sulphites are totally benign.  People with asthma or emphysema should avoid inhaling sulphite powder or the gas that comes off the prepared solution.  It can act as a bronchial constrictor, aggravating any existing breathing problems.


  • Sulphites are a recognized food additive.  The federal government controls their use.  All wines contain sulphites, even those labeled “Kosher” or “Organic.  The legally allowable amount in Canada for wines labeled with “no sulphites” is 70 PPM (30 PPM in the US).
  • Nearly all dried fruits and meats contain sulphites.  Raisins, for instance, have up to 250 PPM.  Frozen orange juice, bacon, dried noodles, (the list goes on and on) all contain sulfites.
  • All grape based wines produce sulphites naturally during fermentation, up to a level of 10PPM.  Even with no extra addition of sulphites, all wines will still contain them.
  • The amount of sulphite provided in Winexpert wine kits will result in a level of between 15 and 30 PPM in a finished wine (about 50 times less than the average commercial wine).
  • Without sulphites, you would have to drink your wine very quickly, before it spoiled, probably within one or two months.