When to Add Sodium Metabisulfite to Wine

Sodium metabisulfite is commonly used in winemaking to protect wine from oxidation and unwanted bacteria or wild yeast. Here are the key stages when it should be added:

• Before Fermentation:
  Add sodium metabisulfite to crushed grapes or juice (must) to kill wild yeasts and bacteria. Wait 12-24 hours before pitching your yeast.
• After Fermentation:
  Once fermentation is complete, add it to stabilize the wine and prevent spoilage by killing any remaining yeast or bacteria.
• During Racking:
  Each time you rack (transfer) the wine to a new container, especially if it has been exposed to air, add a dose to maintain protection.
• Before Bottling:
  Add a final dose of sodium metabisulfite to ensure long-term stability during aging and storage.

Exact dosages depend on your recipe, wine pH, and volume, so always consult a winemaking guide for specific measurements.