Bontonite in kits... why?

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Senior Member
Nov 20, 2008
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I've made a few kits now and I noticed that all the manufacturers seem to start with a bentonite addition. When I look up bentonite, it appears to be a clearing agent, so I'm confused as to why it's being used before the primary fermentation.

Could anyone explain why they do this?

AFAIK, bentonite is not a clearing agent like isinglass, chitosan, kiselsol, etc. In kits, at least, it is used to get rid of protein haze. As such, the kit companies have learned that it can be used at the beginning. This means that less bentonite is required, and less stirring of the bentonite is required. Also, the bentonite aids in fermentation by providing nucleation sites for the yeast.

FYI, when I first started making kits, some brands had large bags of bentonite that were added prior to the other clearing agents. (Boy were some of them fun to re-hydrate.)They also recommended vigourous stirring of the bentonite at that time, which additionally accomplished the degassing. One brand recommended racking from carboy to primary, then adding the bentonite, and vigourous stirring in the primary before adding the other clearing agents and racking back to carboy. So moving the bentonite to the start removed one racking for the winemaker.