In winemaking, the following are some of the main chemical preservatives used:

  • Sulfur dioxide (SO2): A potent antioxidant and antimicrobial agent that helps prevent oxidation and spoilage caused by bacteria and wild yeast.
  • Potassium metabisulfite: A form of sulfur dioxide that is often added in the form of a powder or tablet to the must before fermentation to protect against spoilage and oxidation.
  • Sodium benzoate: A salt of benzoic acid that is used as an antimicrobial agent in winemaking, although it is not as effective as sulfur dioxide.
  • Sodium metabisulfite: A form of sulfur dioxide that is often added during the bottling process to prevent spoilage and oxidation.
  • Tartaric acid: A naturally occurring acid that is found in grapes and is used to adjust the acidity levels in wine.

It is important to note that the use of preservatives in winemaking should be carefully monitored, as overuse can result in off-flavors and aromas in the wine. In many countries, there are regulations governing the maximum levels of chemical preservatives that can be used in wine. Some winemakers choose to avoid the use of chemical preservatives altogether, opting for traditional, more natural methods of preserving the wine.