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Over-Sulfited My Wine

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Melvyn Atkins — Via email asks,
Q

By mistake I added 45 grams of potassium metabisulfite to 16 gallons (60 L) of wine. I have three questions: Is the resulting mixture dangerous? Can it be remedied? And can the grape juice eventually be turned into wine?

A
I’m not sure if in the above question you are referring to having over-added to grape juice or to finished wine. Regardless, adding 45 grams of potassium metabisulfite, which is about 58% sulfur dioxide (SO2), to 60 liters of wine will yield quite a bit of SO2 (to put it mildly). I calculate that’ll get you about 430 ppm (mg/L) of SO2, which is well over the normal 70-100 total SO2 that most finished wines will carry while aging. We tend to want finished wines to carry around 25-30 ppm “free” SO2 and since I don’t know your pH it’s hard to say what you might be carrying here, but I’d be willing to bet it’s so high you can smell and taste some overpowering, unpleasant aromas. It is sometimes possible to remove or reduce sulfur dioxide from wine using hydrogen peroxide (see “Wine Kit First Aid” in the December 2002-January 2003 issue.) but I think your level here is so high that the cure would probably be worse than the disease. Hydrogen peroxide is a strong oxidizer and at
Response by Alison Crowe.