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bernardsmith
11-01-2013, 11:37 AM
Beer makers , I think, talk about cold stabilization. They chill the beer and the idea is that the yeast is "killed" (not true, I think. The yeast merely goes dormant but that is another story) and falls to the bottom of the carboy. But if the second part is true - that the yeast fall out of suspension I wonder if I could cold stabilize mead and then rack the wine into a sanitized carboy and so have a mead with no yeast present. That mead would not need any chemical stabilization (K-M and Ksorbate). I could then backsweeten without fear of refermentation . Or am I barking up the wrong tree here?

questions: does cold stabilization work? If it does what is the minimum temperature needed and what is the minimum time required?
Do the yeast in fact drop out of suspension and fall to the bottom of the carboy? Does this apply to yeast in a 5 gallon carboy or only say, a much shorter container? Does this apply to any variety of yeast or only some kinds of beer or lager yeasts? Thanks

Bob1016
11-01-2013, 11:50 AM
Beer yeast flocculate much better which is why cold stabilizing works, wine yeasts don't work like that. If you cold stabilize at 30F I would not backsweeten for years.
Geometry does have an affect I jut don't know what it is. It is yeast dropping out but there will be more in suspension for a long while.

bernardsmith
11-01-2013, 12:25 PM
many thanks, Bob.

Chevette Girl
11-01-2013, 12:50 PM
There is geometry involved, water treatment facility settling tanks have these diagonal plates so that the suspended matter settles out more quickly.

The thing with cold crashing to settle out the yeast, you'll still only get _most_ of them, not all of them. Even in a perfectly clear mead or wine where you can't see a flashlight beam, there can still be yeast cells present.

If you want to backsweeten safely, you need to chemically stabilize it, sterile filter it, or repeat the backsweetening until it doesn't get consumed because the yeast has reached its tolerance (really, this is step-feeding) and then age it a year or two just to be safe before bottling.

bernardsmith
11-01-2013, 01:50 PM
Totally get what you are saying BUT... even when I stabilize chemically, I am not killing the yeast. What is to prevent more virile cells from reproducing and fermenting the sugars I have just added. What is it that beer makers are doing when they cold stabilize that wine makers are not doing? Is it simply because a beer maker is more likely to drink their beer with weeks after cold stabilization whereas we are only likely to start drinking the mead 12 or 24 months after bottling? Are beer or lager yeasts more likely to flocculate and be left behind during racking than wine yeasts when cold stabilized?

MikeTheElder
11-01-2013, 02:50 PM
Totally get what you are saying BUT... even when I stabilize chemically, I am not killing the yeast. What is to prevent more virile cells from reproducing and fermenting the sugars I have just added. What is it that beer makers are doing when they cold stabilize that wine makers are not doing? Is it simply because a beer maker is more likely to drink their beer with weeks after cold stabilization whereas we are only likely to start drinking the mead 12 or 24 months after bottling? Are beer or lager yeasts more likely to flocculate and be left behind during racking than wine yeasts when cold stabilized?

Campden will sterilize your finished produce to prevent spoilage and sort of "stuns" the yeast.

Potassium sorbate disrupts the reproductive cycle of the yeast so that no new yeast cells are created and the living cells eventually die of old age.

bernardsmith
11-01-2013, 04:22 PM
But even human contraceptives are not 100 percent effective. My question is whether chemical castration of yeast is statistically more effective than putting the yeast into suspended animation from the cold and allowing them to drop to the bottom of a carboy and then racking the mead from a point above where the yeasts are located? Is there any hard data on this or do we simply "know" that adding chemicals is more effective? Is it that wine yeasts don't shut down when exposed to very cool temperature but only get knocked unconscious by a cocktail of KM and KSorbate? And if they are stunned by the cold are they able to remain in suspension? Beer makers claim that the yeasts they use drop to the bottom of their fermenters. And if they are KO'd by chemicals does that mean every last yeast cell is out of the game? Are you saying that yeasts don't have their Mike Tysons and Floyd Mayweathers? The exceptional few that are tougher than the others... a bit like anti biotic resistant strains of bacteria.
just askin' ... Just askin'

theEnvoy
11-01-2013, 04:28 PM
But even human contraceptives are not 100 percent effective. My question is whether chemical castration of yeast is statistically more effective than putting the yeast into suspended animation from the cold and allowing them to drop to the bottom of a carboy and then racking the mead from a point above where the yeasts are located? Is there any hard data on this or do we simply "know" that adding chemicals is more effective? Is it that wine yeasts don't shut down when exposed to very cool temperature but only get knocked unconscious by a cocktail of KM and KSorbate? And if they are stunned by the cold are they able to remain in suspension? Beer makers claim that the yeasts they use drop to the bottom of their fermenters. And if they are KO'd by chemicals does that mean every last yeast cell is out of the game? Are you saying that yeasts don't have their Mike Tysons and Floyd Mayweathers? The exceptional few that are tougher than the others... a bit like anti biotic resistant strains of bacteria.
just askin' ... Just askin'


Abstinence is the best response to your dilemma.

Midnight Sun
11-02-2013, 01:58 AM
snip... My question is whether chemical castration of yeast is statistically more effective than putting the yeast into suspended animation from the cold and allowing them to drop to the bottom of a carboy and then racking the mead from a point above where the yeasts are located? ...snip

Consider a typical lager process:
1. Pitch yeast at 65F.
2. Cool to 45-55F during fermentation.
3. Raise temp to 60-62F at the end of fermentation for max attenuation (optional)
4. Chill to 35F for 4-6 weeks (longer for certain styles).
5. Rack, add priming sugar, and bottle. Or keg.

The process above is somewhat simplified, but you can see that even after 6 weeks at 35F there are still sufficient yeast suspended in the beer to bottle prime. Some styles are lagered a long time (1 year), but there are probably still a few viable yeasts floating around. Might take a while to bottle prime without adding more yeast, but it probably still could be done.

You have 3 options: sterile filter, heat pasteurize, or chemical stabilize. Gonna have flavor loss with sterile filtering and you will have a negative impact on your flavors when heat pasteurizing. Which leaves... the chemical one-two punch. ;)

bernardsmith
11-02-2013, 07:17 PM
Midnight Sun, Many thanks. I currently K-M and K-Sorbate any wine I backsweeten and K-M any wine I ferment dry. You convinced me that cold stabilization is not a viable proposition. So I will stick with the Sorbate and bisulfate cocktail. PS it is really good to know that there are likely to be enough viable yeasts in the mead after a year for me to prime the mead and expect there to be enough CO2 produced after a month or two for the mead to be considered sparkling without any need for me to add another batch of yeast to the priming sugar. (I say this because in another couple of months I should be ready to prime a hopped mead and that will be the first mead I have made to be sparkling).

Midnight Sun
11-02-2013, 09:30 PM
Your welcome! For your 1-year sparkling mead, it might very well take two months or more to prime. The longer yeast sit, the fewer viable cells there are. Maybe set one bottle aside and test at 2 months? If you use crown caps instead of cork and cage, then t would be easy to get into the bottles and add some yeast if the old ones get stubborn.

Personally, I have not tried priming something more than 3 months after racking. I then let it age for a few more months before drinking.

Medsen Fey
11-03-2013, 08:30 PM
The easiest way to do a test bottle is to put some in a PET soda bottle. If and when the bottle gets firm like a soda bottle, you know it's done.

bernardsmith
11-04-2013, 12:13 AM
Using a soda bottle sounds like a great technique. Thanks

Oddball
11-09-2013, 05:44 PM
Beer makers , I think, talk about cold stabilization. They chill the beer and the idea is that the yeast is "killed" (not true, I think. The yeast merely goes dormant but that is another story) and falls to the bottom of the carboy. But if the second part is true - that the yeast fall out of suspension I wonder if I could cold stabilize mead and then rack the wine into a sanitized carboy and so have a mead with no yeast present. That mead would not need any chemical stabilization (K-M and Ksorbate). I could then backsweeten without fear of refermentation . Or am I barking up the wrong tree here?

questions: does cold stabilization work? If it does what is the minimum temperature needed and what is the minimum time required?
Do the yeast in fact drop out of suspension and fall to the bottom of the carboy? Does this apply to yeast in a 5 gallon carboy or only say, a much shorter container? Does this apply to any variety of yeast or only some kinds of beer or lager yeasts? Thanks

I believe what you are referring to is "cold crashing". For beer brewers this is done to drop as much yeast out of suspension and to obtain a more compact yeast cake before bottling. Most do it to help with clarity. There is still plenty of yeast in suspension (and there has to be) in order to bottle carbonate at least.