Register Now!
The HomeBrew Forum > Beer Brewing Talk > General Beer Brewing Discussion > Stuck Fermentations Dont Exist....Discuss

Help Support The Homebrew Forum by donating using the link above or becoming a Supporting Member.
Reply
 
Thread Tools Display Modes
Old 02-12-2013, 01:38 PM   #1
johnnyboy1965
Senior Member
 
Join Date: Mar 2011
Location: Solihull, West Mids
Posts: 2,051
Liked 426 Times on 291 Posts
Likes Given: 17

Default Stuck Fermentations Dont Exist....Discuss

Contraversial (sp) I know, but it is the nature of the yeast beast to do its job
johnnyboy1965 is offline  
 
Reply With Quote
Old 02-12-2013, 01:42 PM   #2
graysalchemy
Member
 
Join Date: Apr 2010
Posts: 54
Liked 18 Times on 13 Posts
Likes Given: 1

Default Re: Stuck Fermentations Dont Exist....Discuss

So what is your theory on this then?

You can't just post an opener with out giving your side of it. Or are you just lighting the blue touch paper and walking away, to watch at a distance?
graysalchemy is offline  
 
Reply With Quote
Old 02-12-2013, 01:50 PM   #3
calumscott
Senior Member
 
Join Date: Sep 2011
Posts: 313
Liked 42 Times on 26 Posts

Default Re: Stuck Fermentations Dont Exist....Discuss

Yeast, being a living thing, is subject to environmental pressures changing its response to its environment to suit it's own agenda be that survival of the gene through growth and replication or survival of the organism through dormancy.

"Stuck ferments" or rather dormant yeast exist. Stuck ferment tactics as described in the very good how to guide change the environment to illicit a response from the organisms.

Pretty basic environmental microbiology which has been harnessed by brewers and cidermakers for various effects over the centuries. In fact, the stuck ferment is engineered into the process of keeving to make sweet, naturally carbonated cider.

Irrefutable I'm afraid.

I've had several in wine, touch wood, the ones I thought I had in beer turned out to just be higher FG (and very tasty) beers.
calumscott is offline  
 
Reply With Quote
Old 02-12-2013, 01:52 PM   #4
johnnyboy1965
Senior Member
 
Join Date: Mar 2011
Location: Solihull, West Mids
Posts: 2,051
Liked 426 Times on 291 Posts
Likes Given: 17

Default Re: Stuck Fermentations Dont Exist....Discuss

My thoughts are like this....people who say they have a stuck fermentation often refer to eg "OG 1.040 stuck at 1.020". Therefore there must be viable yeast in the brew, to drop it by 0.020. The yeast has done its job, its consumed all the available sugars present in the beer. Yeast will not stop working if there are sugars available, ie ..if there is live yeast and sugar available it will carry on fermenting.
johnnyboy1965 is offline  
 
Reply With Quote
Old 02-12-2013, 02:00 PM   #5
calumscott
Senior Member
 
Join Date: Sep 2011
Posts: 313
Liked 42 Times on 26 Posts

Default Re: Stuck Fermentations Dont Exist....Discuss

Quote:
Originally Posted by johnnyboy1965
if there is live yeast and sugar available it will carry on fermenting
Sorry, no. You can have a stuck ferment, take the yeast from it and ferment something else with suitable conditions for that yeast. Likewise you can take a stuck brew and add it to a different yeast and have it chew down the sugar left behind.

The "stick" is when the yeast moves from a growth and replication phase to a dormancy phase where it hopes to ride out the current adverse conditions in the hope that they will change. In the case of keeving that's done by taking out all the other nutrients required for active yeast growth so it can't utilise all the sugar. It's not dead, add yeast nutrient and the whole thing would start up again.

Take the extreme end of fermentation - Brewdog's Ghost Deer at 28%ABV - all fermented! That (if I'm right on the theory) takes multiple fermentations with different yeast strains, each one carefully grown and conditioned for a particular stage of the fermentation, they all give up eventually and the beer is transferred to another yeast cake of a yeast grown to tolerate that particular level of (poisonous) alcohol.

Many stuck ferments in the pursuit of one crazy beer.
calumscott is offline  
 
Reply With Quote
Old 02-12-2013, 02:04 PM   #6
markmark
Senior Member
 
Join Date: Aug 2013
Posts: 276
Liked 2 Times on 2 Posts
Likes Given: 1

Default Re: Stuck Fermentations Dont Exist....Discuss

Quote:
Originally Posted by johnnyboy1965
My thoughts are like this....people who say they have a stuck fermentation often refer to eg "OG 1.040 stuck at 1.020". Therefore there must be viable yeast in the brew, to drop it by 0.020. The yeast has done its job, its consumed all the available sugars present in the beer. Yeast will not stop working if there are sugars available, ie ..if there is live yeast and sugar available it will carry on fermenting.
Even if it gets cold?
I personally think that most stuck fermentations are caused by the temperature being too low. At the start of ferment the conditions are ideal for the yeast to work....aerated wort, food, no alcohol present, fresh and healthy yeast.....a small temperature drop won't matter too much, and the initial stages are very exothermic too. But as the conditions deteriorate (in terms of whats best for the yeast), the yeast is more likely to drop out if it gets a little cold.

What advice do we normally give for a stuck ferment.......rouse gently and increase the temperature a little??
markmark is offline  
 
Reply With Quote
Old 02-12-2013, 02:10 PM   #7
johnnyboy1965
Senior Member
 
Join Date: Mar 2011
Location: Solihull, West Mids
Posts: 2,051
Liked 426 Times on 291 Posts
Likes Given: 17

Default Re: Stuck Fermentations Dont Exist....Discuss

Every single yeast strain will carry on working if there is sugar present, you cannot stop it.....unless you add (I think its potassium sorbate) which kills off any live yeast.
If you brewed a beer with a bog standard yeast at 1oC, eventually it will ferment out.
johnnyboy1965 is offline  
 
Reply With Quote
Old 02-12-2013, 02:17 PM   #8
wezil
Senior Member
 
Join Date: Apr 2012
Posts: 413
Liked 3 Times on 3 Posts
Likes Given: 1

Default Re: Stuck Fermentations Dont Exist....Discuss

Hi nice to know I'm not the only one who makes somewhat controversial posts. lol!
And my tuppence worth is that stuck is probably the wrong word, I think paused might be better, or even a hibernated ferment.
As you can re-rouse the yeast (usually)! And it could be that just leaving the wort/must to It's own devices will start it up again
at some point. Although good management 'should' help prevent 'sticking'.
wezil is offline  
 
Reply With Quote
Old 02-12-2013, 02:28 PM   #9
johnnyboy1965
Senior Member
 
Join Date: Mar 2011
Location: Solihull, West Mids
Posts: 2,051
Liked 426 Times on 291 Posts
Likes Given: 17

Default Re: Stuck Fermentations Dont Exist....Discuss

Quote:
Originally Posted by markmark
Quote:
Originally Posted by johnnyboy1965
My thoughts are like this....people who say they have a stuck fermentation often refer to eg "OG 1.040 stuck at 1.020". Therefore there must be viable yeast in the brew, to drop it by 0.020. The yeast has done its job, its consumed all the available sugars present in the beer. Yeast will not stop working if there are sugars available, ie ..if there is live yeast and sugar available it will carry on fermenting.
Even if it gets cold?
I personally think that most stuck fermentations are caused by the temperature being too low. At the start of ferment the conditions are ideal for the yeast to work....aerated wort, food, no alcohol present, fresh and healthy yeast.....a small temperature drop won't matter too much, and the initial stages are very exothermic too. But as the conditions deteriorate (in terms of whats best for the yeast), the yeast is more likely to drop out if it gets a little cold.

What advice do we normally give for a stuck ferment.......rouse gently and increase the temperature a little??
My first port of call would be to take a accurate gravity reading. As home brewers tihs is impossible, but the best we can do is by using two or three different hydrometers. If you are now sure that your beer is at eg 1.020, then here is a little chefs tip.....taste it....believe me on this one......mix 1li of water and add 20g of sugar...take a sample of your beer, and taste test them side by side.
johnnyboy1965 is offline  
 
Reply With Quote
Old 02-12-2013, 02:43 PM   #10
johnnyboy1965
Senior Member
 
Join Date: Mar 2011
Location: Solihull, West Mids
Posts: 2,051
Liked 426 Times on 291 Posts
Likes Given: 17

Default Re: Stuck Fermentations Dont Exist....Discuss

My above post is wrong and will not work...I didn't take into account of the bittering hops
But you can judge it by:-
1 x Li Plain water
1 x Li water plus 20g of sugar.
This might give you a beeter ides
johnnyboy1965 is offline  
 
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Newest Threads