Can you use bentonite before fermentation? Conflicting sources

Question

Can you use bentonite before fermentation, or must it be used after fermentation? This source says you can use it before pitching yeast. https://winemakersacademy.com/bentonite-clarify-wine/

Some kit manufacturers (such as Winexpert) have you add bentonite in the very beginning of the wine making process, right before the yeast. That is so the bentonite will start clarifying the wine as it’s fermented. This is one of the only fining/clearing agents that can be added pre-fermentation.

It sits on the bottom of the fermenter and as carbon dioxide bubbles form during fermentation the bentonite is carried up to the free surface. Along the way it collects positively charged particles. When the bubble reaches the surface and pops the bentonite falls back down to the bottom collecting more particles along the way.

Thus your wine is clarifying during the entire fermentation process.

This source says it must be after. https://eckraus.com/wine-making-bentonite/

It should also be noted here that the Bentonite should not be added to the wine until the fermentation is complete.

Answer 1

Yes you can, both can be done.
I usually follow instructions I am provided. I have three books on the subject:

• The Encyclopedia of Home Winemaking - mentions to add it before yeast.
• Techniques in Home Winemaking - mentions for best results to add it before, but can also be used after first or second racking, before stabilization.
• Modern Winemaking - mentions to use it after fermentation but also before in some cases.

I personnaly stopped using bentonite because I find it extracts too much color and flavour in red wines.

Answer 2

Bentonite is a fining agent (clarifier) that can either be added in moderate amounts before the fermentation or in larger amounts after the fermentation. It is a clay that is very unique because of the fact that it has a static charge that is stronger than usual. It is this property that makes Bentonite valuable as a fining agent.

Bentonite is able to collect dead yeast cells and drag them to the bottom of the fermentation vessel, leaving a clear wine. Being continually suspended throughout the wine is one of the key factors of how well the Bentonite will work. If it is added and just sits at the bottom of the fermenter, it will do very little in the way of clearing a wine.

When added before the fermentation, not as much Bentonite is needed because it is relying on the fermentation activity to keep it stirred up. It is constantly being churned up by the rise of CO2 gas bubbles that are being created by the wine yeast. This is why your wine recipe only calls for 4 teaspoons. If added after the fermentation, more is needed to be effective, and several periodic stirring sessions are required by the wine maker, as well.

This is the post copied from ECKraus website. I just made a batch of Welch's grape juice wine. Sweet. I bottled it today. Its pretty tasty. I added bentonite after the 1st rack and stirred the wine couple of times after I added it. It took seven days to completely clear. Next batch, I am going to add it during primary fermentation.

Answer 3

The product data sheet that comes with the Pectolase enzyme I use is quite clear:

Do not use bentonite when adding the enzymes since they will be adsorbed.

Pectolase is, of course, added before fermentation.

Bentonite has several effects: it can adsorb some components and reduce color, but also remove things you want, such as your enzymes. In practice, though, bentonite is mainly used a flocculant, and flocculation / clarification don't make much sense before the fermentation is complete. So using bentonite before the end of fermentation makes little sense, in my opinion.

In closing, i see that most instructions to add it early come from older literature. Offhand I'd say that the insights on how to best use it have progressed over the past century or so.