Author Topic: Fermentastion Issue  (Read 3488 times)

Offline cousindave

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Fermentastion Issue
« on: August 30, 2012, 06:58:32 AM »
Friends,

I have a fermentation issue you may be able to help out with: Recently brewed my first BarleyWine and believe I have a stuck fermentation. Due to some poor attention to detail on my part I would up with a 3hour boil in order to get volumes/gravity where they were intended. My concern is that such a long boil will caramelize the sugars too much. Is it possible to caramelize to the point that the sugars are no longer fermentable? My chemistry knowledge is light in this area, so I'm not sure if this is something that happens with a longer boil? Perhaps I should just let it sit in secondary another 4 months or so...?  :)

Whay do you folks think?

Just for the sake of discussion:
This was an AG brew.
OG was 1100
Pitched ~400ml fresh yeast slurry (1334) from a local brewery
Fermeted at ~68F till I noticed it sticking, then moved to a warmer area of the house (~74F)
Current SG 1050
Brewed July 22, 2012

Offline philm63

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Re: Fermentastion Issue
« Reply #1 on: August 30, 2012, 07:22:15 PM »
I've never heard of sugars being cooked so long they become less fermentable. Not saying it can't happen, but I suppose it is possible to damage or otherwise reduce the nutrient content of the malt to the extent it becomes less fermentable or at least more of a challenge for your yeast...?

That being said; I'd have to say it is more likely that your yeast is simply exhausted. Even if the pitch rate was dead-on, nutrient or oxygen deficiencies can easily lead to a stuck fermentation with high-gravity brews.

Did you aerate your wort sufficiently prior to pitching? And possibly again at 12-18 hours? An aquarium pump, filter, and a sintered stone would be useful for this task. For higher-gravity beers, oxygen is key to a good full fermentation. In a pinch; you could always pitch a small starter of a clean yeast (such as WLP001) at high krausen to restart fermentation and finish this one out.

You mention it is currently in the secondary. Did you take an SG reading prior to racking off the yeast cake? Pulling too soon w/o confirming fermentation is complete will leave too little yeast to finish the job effectively, as well as not allowing the yeast sufficient time on the cake to clean up after itself. Just a thought.
On Tap: Oatmeal Stout, IPA
Fermenting: Air
On Deck: Kolsch

Offline MaltLicker

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Re: Fermentastion Issue
« Reply #2 on: August 31, 2012, 09:29:38 AM »
You mention it is currently in the secondary. Did you take an SG reading prior to racking off the yeast cake? Pulling too soon w/o confirming fermentation is complete will leave too little yeast to finish the job effectively, as well as not allowing the yeast sufficient time on the cake to clean up after itself. Just a thought.


That's my guess, with an OG of 1.100.  I would expect to sit on primary for at least four weeks to fully ferment and clean up before racking it off.    The slurry of yeast sounds big enough assuming it was healthy and a high ratio of cells to trub. 

Offline cousindave

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Re: Fermentastion Issue
« Reply #3 on: September 02, 2012, 04:21:52 PM »
Thanks guys. Good advice, I appreciate your thoughts.

 

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