Experiment: flocculating farmhouse ale (wy3275) with bentonite

I'm trying to up my experimenter chops. So after some searching that didn't turn up much, I'm trying this myself.

Problem statement:
I'm using Wyeast 3725 to do a warm (and very dry) farmhouse ale in my very warm apartment. This yeast is fun -- 1.045 to 1.007 and still bubbling with a clean effervescent taste, but it *really* doesn't flocculate. A 1qt sample in the fridge took >1week to fully clear. I'm looking for something cheap, simple, and vegetarian to speed the process along.

Proposal:
Bentonite is very cheap, and I have some, and I'm lazy. Some background -- bentonite is like really tiny slate. It's made of lots of wide, thin sheets. The surface of its plates have the same charge as yeast, so it isn't usually used for yeast flocculation. But the edges of those plates have the opposite charge of yeast (since the plates must be electrically neutral). I'm thinking that the edges of the plates might bind to multiple yeast cells and help form larger aggregates that fall out.

The set-up:
I just racked from a ~10 day, 75-80 degF primary fermentation. I racked one gallon onto 1/2 tsp of bentonite boiled in 4oz water. The rest of the batch was racked into a large carboy. It's not an apples-to-apples comparison, but...

Status so far:
The bentonite settled into a distinct, darker layer within 24 hours. A significant layer of lighter colored yeast deposited on top. The test beer is still pretty cloudy. It's hard to tell if the control beer has significantly less yeast deposited so far, or if there's any difference in clarity between the two. I'll pulled my first sample of test beer earlier today and stuck it in the fridge to settle. I'll have initial flavor tests and pics up soon.

Here's a pic of the control batch. If anyone has anything they'd like me to test/check, I'm open to suggestions...

Do you have both samples under the same conditions (ie in the fridge)? I just got a kit with this yeast, so I am looking forward to the results of your experiment!

My experience with bentonite is extremely limited, so take this with large chunks of NaCl. Don't you need to stir up bentonite repeatedly (unlike some othe fining agents) for it to have the best effect?

In winemaking (the only place I've used it) I've added it before fermentation has begun, and my understanding was that fermentation activity agitates the wort (must) sufficiently for the bentonite to do its thing. If added after primary fermentation is complete, I thought you had to do that manually. Otherwise I believe it just drops out without having collected any (or much, at least) payload.

eesteve said:

Do you have both samples under the same conditions (ie in the fridge)? I just got a kit with this yeast, so I am looking forward to the results of your experiment!

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Both the carboy and the gallon jug are at room temp now (~78F) -- they're still bubbling away slowly. They're both still too cloudy to see any difference in yeast density by eye.

I've now tasted 2 different 4oz samples (each had at least 12 hours to floc/clear a bit in the fridge). So far I'm a big fan of the dry, clean flavor after an 80degF primary fermentation.

I'll try pulling one sample from each into 50ml vials tonight and let them sit in the fridge for 24 hours and see if I can detect any flavor/sediment differences side-by-side.

airving said:

In winemaking (the only place I've used it) I've added it before fermentation has begun, and my understanding was that fermentation activity agitates the wort (must) sufficiently for the bentonite to do its thing.

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Interesting, I didn't find that in my searching. Separately, my understanding was that, in wine, it was mostly used to grab proteins to avoid chill haze in wine, particularly whites. Do you know if it helps at all with yeast flocculation in wines?

helmingstay said:

Interesting, I didn't find that in my searching. Separately, my understanding was that, in wine, it was mostly used to grab proteins to avoid chill haze in wine, particularly whites. Do you know if it helps at all with yeast flocculation in wines?

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Bentonite use in wine is a method of obtaining protein stability -which there is no industry standard and differs across the board for varietal and style. It is used for reds and whites and affects wine stability by removing complexing factors formed between polyphenols and tartaric acids in reds and proteins and tartaric acids in whites. It non-selectively removes proteins, peptides, and amino acids in wine and may 'adversely' affect fermentation rates. As much as 50% reduction in total nitrogen as well as reductions in amino acids (15-30%) with bentonite additions of 1 g/L depending on type of bentonite used. Using bentonite during fermentation reduces nonprotein nitrogen (approx twofold) and also reduces lees volume and increases levels of H2S. Bentonite used post-fermentation remove residual wine proteins and nearly equal amounts of protein and nonprotein nitrogen. It generally increases the aluminum content twofold and increases in iron content have also been recorded.

helmingstay said:

I'll try pulling one sample from each into 50ml vials tonight and let them sit in the fridge for 24 hours and see if I can detect any flavor/sediment differences side-by-side.

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Pics of 2 samples, + is clay, - is none. I switched positions to check lighting & got the same result, + is definitely clearer. Any chance fermention vessel size/height could be effecting clarity?

These are pics (taken 2 days ago) of yeast washes that have been in the fridge since the labelled date. You can see that it does finally fall out, but it sure takes it's sweet time!

[Edit - doublepost]

(Not totally thrilled w/the android app, fwiw)

Two pics of the test vials showing less opacity & yeast sediment for treatment batch.

Pre-bottling taste tests are in. The results are pretty dramatic. The clay stripped a *lot* of flavor and even body from the beer -- I'd use 1/2 to 1/4 as little if I tried this again. I'm now really curious to taste the final bottled & carbonated results.

Thanks for the update! Your last post makes me think I'll stay away from this method. I'd rather drink cloudy beer than strip all the flavors out of it. Of course, if your bottled and carbed results are substantially different I'll reconsider my position

eesteve said:

I'd rather drink cloudy beer than strip all the flavors out of it.

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I was thinking last night that this might actually work for a CAP to get a bright, clean finish without mechanical filtering. It does seem that a little bit goes a long way, though!