Chemicals of various types can be added to the wine either to clarify it or to prevent spoilage. This guide only presents a few of the most common wine chemicals and their purpose. For specific dosing or usage, please consult the manufacturer, supplier, and where applicable the Material Safety Data Sheet (MSDS).

Sulfur dioxide (SO2) - This chemical is added to the wine to stop bacteriological activity, to inhibit yeast growth, and as an antioxidant. A certain amount of SO2 is necessary to prevent wine spoilage and oxidation, but too much can lead to sulfur off-flavors and off-odors. Potassium metabisulfite is 58% SO2. Free SO2 is the active form in the wine.

Bentonite - This clay material is mixed with water into a slurry and added to the finished wine to precipitate proteins.

Enzymes - Various pectic enzymes can be used immediately after crushing the grapes to promote the settling of the juice before initial racking in whites. In red wines, enzymes can also work to maximize color extraction.

Diammonium phosphate (DAP) - A yeast nutrient that promotes yeast growth and activity.

Others - The array of other possible additives and clarifying agents is too long to list here. Take some time to look at a wine supply catalog if you need help with a specific problem. Also, be sure to have cleaning supplies on hand for your containers and bottles, again making sure that all cleaners are food safe.