Does bentonite kill yeast in wine?

Question

I don’t want to use potassium sorbate or sulfite to kill the yeast in wine. Does bentonite help with killing the yeast in wine?

Answer 1

No, it doesn't. Bentonite is a clarifying agent, similar to Gelatin. It helps settle the yeast and other haze causing elements, but it does not kill the yeast. Sulfites don't actually kill yeast unless you put a lot into your wine. The legal limit is 350ppm, but your wine would probably taste pretty bad at those levels.

Answer 2

The proper agent to stop fermentation in wine is potassium sorbate. This does not kill the yeast, but renders it sterile by blocking its ability to reproduce. Sulphites (typically sodium metabisulphite in the form of Campden tablets) don't kill yeast either but act as an oxygen scavenger to stabilize the wine by preventing oxidation. Ascorbic acid (a.k.a. vitamin C) does the same, using a different mechanism.

Typically the process used is something like this:

1. Add ascorbic acid to inactivate the yeast;
2. Add bentonite sludge to settle the yeast and other solids out of suspension;
3. Stabilize the wine with sulphites and/or ascorbic acid.