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What Sulfites Actually Are
Sulfur dioxide (SO₂). A gas that becomes a salt when dissolved. Used for thousands of years in winemaking, food preservation, and medicine. In wine, sulfites prevent oxidation (the wine going brown and flat) and microbial spoilage (the wine turning into vinegar).
Yeast itself produces small amounts of sulfites during fermentation — even wines labeled “no sulfites added” have some sulfites naturally. The legal label threshold is 10 mg/L; below that, no warning is required.
For context: dried apricots can have 1000–2000 mg/L of sulfites. Wine usually has 50–150 mg/L. White wine generally has more than red (because reds have natural antioxidants from skins). Sweet wines have the most (because residual sugar invites spoilage).
