Originally Posted by Tom
A fining agent made of clay and used primarily for clearing white wines of sediment remaining in suspension.
Not the best description of bentonite that I have seen. For one thing, it is also used in some red wines. It's primary use is removing protein haze.
Kit manufacturers recommend that it be used pre fermentation because the lift provided by CO2 helps it to circulate thru the must/wine, thus requiring less bentonite. It also provides nucleation points for the yeast during fermentation.
I believe that bentonite conflicts with something used with grapes...perhaps pectic enzyme??