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Why Winemakers Use Them

Two jobs: stop oxidation, stop spoilage. When wine is exposed to oxygen, it slowly browns and loses fresh aromas — the same way an apple browns after cutting. Sulfites bind to oxygen molecules before they can damage the wine.

The second job is preventing bacterial spoilage. Without sulfites, wine is at risk of unwanted bacteria (like Acetobacter, which converts wine to vinegar) and unwanted yeasts (like Brettanomyces, which produces “barnyard” off-flavors). A small dose of sulfites keeps these microbes quiet.

The choice isn't binary. Most modern winemakers use enough sulfites to stabilize, not the maximum. Skilled winemakers might use 30 mg/L; less careful ones, 150 mg/L. EU legal limit is 200 mg/L for red, 250 for white. Most quality wines are well below.

A winemaker checking a wine tank in a cellar
The winemaker's invisible bodyguard. Sulfites do their work and disappear.