Flocculation issue

[billk]

I have been using the Whitelabs 920 lager yeast for over a year now for two different beers. Recently I have had a problem with it not dropping out of suspension after fermentation, but only in the one style, in the other no problems. The beer has been lagering for almost 6 weeks now and has been crashed to 32 for almost a week and a half, I've hit my terminal gravity and can't figure out why it will not flocculate. This is the second batch this has happened with and I used a generation of the yeast in between the two for my other beer without a problem. I filter before I transfer to my SV but with my plate and frame it makes for a slow transfer. Any ideas or suggestions are greatly appreciated.

BillK

[Faustino Silva]

Yeast Flocculation issue

I would suggest acid washing 2.2 ph for an hour before pitching. I am a big fan of glassings to clear yeast timely. If you are not familiar with using glassings, I can give you direction.

Cheers and Blessings
Faustino

[Greenbrewmonkey]

Hmmm. I think acid washing would only help if the problem is related to some contaminating microorganism in the pitching yeast. It may even worsen the situation as acid washing can greatly reduce yeast viability and vitality in the next pitch. (Affecting fermentation, flocculation, etc.)

Flocculation can be a tricky issue, and I'm afraid that without a lot more info it will be hard to address your case in specifics. I have found over the years that different worts / beers will have sometimes profound effects upon flocculation. In general, I tend to see better flocculation with amber and darker colored beers. Again, a wort content issue. Now assuming that this is a new problem, never before happened, not even just a little, then that may not be the issue. But it might. How old is the yeast? Lager strains can change rather rapidly. Perhaps yours is? Fermentation characteristics including flocculation are some of the first changes you might notice. As this happens small differences in wort composition can start to have more easily noticed effects. Other areas to look could be water content, Ca levels, zinc, etc. Aeration can also effect yeast growth and flocculation, so are both worts treated to the same levels of O2? If what you are seeing is some other type of haze and not actual yeast, that opens up a whole new can of worms.

I would agree, for super fast, super bright, unfiltered beer fining can be a wonderful thing. Prepared isinglass treatments such as Biofine and Castklear combined with a proper amount of silica/hydro/zero-gel can work wonders. Of course you have to explain to all the vegetarians that there is no actual "fish" left in the beer.

Some help, or no help at all,
Aloha,
Ron

[jay]

Floculation

One other possibility is that changes in malt can cause the yeast to stay in suspension. If you are using different malts I would suggest calling your maltster and discussing the problem. If all other factors are consistant but the malts you are using are different then this should be one of the first things you check.

Good luck
jay

[Faustino Silva]

Flocculation issue

How acid washing helps:

It tends to reduce esters, by limiting viable yeast, to yeasts with two buds or less. How that would effect flocculation is, many times yeast will not flocculate if they have multiple buds. Acid washing kills the yeast with three or more buds, thereby standerdizing your brews, reducing esters, and helping flocculation.

Cheers and Blessings
Faustino

[dick murton]

Where on earth did you get that info from ? If you acid wash warm yeast, or yeast that has been stored for a long time and is not particularly healthy as a result, then this will kill off yeast, and may affect flocculence. Some yeast strains are more susceptible to even good acid washing conditions, but most good healthy yeast will survive quite happily. The idea of acid washing is NOT to affect the yeast, but to kill of bacteria. You cannot kill off wild yeasts specifically though.

I am genuinely interested in knowing the source of the comments though.

Cheers

[Ted Briggs]

Another concideration

Also think about your yeast cropping. Yeast cropping can actually be like genetic manipulation. If you crop twice from the same fermentor the first will naturally contain more flocculent yeast than the last crop. Over several generations this can really add up! Maybe this explains why one batch from the same generation was fine...was it the bottom (therefore faster falling) yeast?
I try to split up multiple crops for this reason, filling corneys' simultaneously and then storing them cold to re-pitch. My thinking is that this results in a more homogenous pitch for the next generation.
Also I love my zero gel- are you sure the haze is yeast and not protein?
(ps- go get em' Dick! )

[Alex T]

hi,

not knowing your brewing water or what beers you are making, i thought that a calcium deficiency may be causing the poor flocculation. most brewers add some calcium sulphate or calcium chloride to the mash, so perhaps this is not the problem.....

i also thought that it might be haze you are mistaking for yeast. the easiest way to tell is to mix an amount of caustic into a sample of beer - if the haze is protein, the caustic will clear it up. if the haze is still there, it is yeast.

interesting anyway, let everyone know what you find out.

cheers,

alex

[BrewBoy]

Hello -

I actually just had the same thing happen. It's happened once before,and both times on an IPA I make in a 7 BBL batch. Previously, I dry-hopped with leaf hops. This time I dropped pellets in the top.

The problem is spurradic. I've brewed this beer 10 or more times and it's happened twice. Full attenuation is reached, and it's crashed and left cold for up to 8 days with minimal clearing. It is certainly yeast in suspension. I can taste it, and way too thick to be anything else, really.

It clears after I add finings and transfer. The yeast is 2nd or 3rd generation - relatively fresh.

Anyway, if you learn any other possible causes, let me know!

[ATB Consulting]

I would like to add a comment to Alex T's post.
Another way to detect a protein haze (which can be detected at cold temps) is to microwave a sample of beer to room temp (68 F), at which point it should be relatively transparent.

I have produced lagers on a production scale and experienced haze problems from yeast, but that was taken care of by isinglas. Protein haze is a more difficult problem to remedy.

If protein haze is an issue try PVPP (aka Polyclar). This can be obtained from Crosby & Baker (in the U.S.) and may be used in the bright tank.

Also, please look at the protein level in the malt you are using by requesting a spec sheet with every shipment of malt you recieve, there may be a variance. American malts tend to have higher protein levels than Euro malts.

Cheers,
Aaron