Bentonite is a special kind of food-grade, volcanic clay first discovered in the 19th Century in Fort Benton, Wyoming. The yeast in the wine attaches itself to the tiny clay particles, and this increases fermentation. After the fermentation is finished, the Bentonite settles out completely.


Pronounced “kahy-tuh-san” is a clearing agent to control spoilage yeast.  Chitosan is a fibrous substance made from shrimp shells and the shells from other crustaceans. It is used as a fining agent in wine making, and works slightly differently from Kieselsol. Both Kiesesol and Chitosan should be used to clarify wine and used in the correct order: first adding Kieselsol and then Chitosan. If you accidently add these in the reverse order, wait about 3 days, rack your wine, and then add them again in the correct order. Chitosan is also used in some cheese making processes.  Although it is derived from shellfish, there is no danger of allergic reactions to the product, as there are no allergens left after Chitosan is processed.


Pronounced “kee-sel-sol” is a colloidal silica used to remove dead yeast and other undesirable solids from wine. Kieselsol is a fining (clearing) agent, added to wine to help clarify it. Fining agents gather tiny suspended particles in your wine, making them fall to the bottom of your carboy to be easily removed when you rack your wine. The end result is to help make your wine nice and clear. In the past things like egg whites, gelatin and even Irish moss have been used to clarify wine. 


Potassium Metabisulphite is a stable salt of sulphur used in winemaking all over the world. When you add it to your wine, it stops oxidation (that is, it keeps the wine from going brown and losing flavor), and it stops bacteria from spoiling the wine.


Potassium Sorbate is an additive used to stabilize wines. This means that sorbate is used to prevent spoilage by yeasts and molds in a finished wine. When you rack your wine, you remove almost all of the yeast used during fermentation. Most of the yeast is dead, having done its job in fermentation, but some small amount remains active. Sorbate prevents fermentation from beginning again, by stopping any remaining active yeast cells from working.