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Old 02-18-2013, 12:36 PM   #1
frankvw
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Feb 2011
Johannesburg, South Africa
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Hi everyone,

Yesterday I brewed a full grain oatmeal stout. I mashed at 69 degrees C (rather high because I want this to be a sweetish, full bodied beer). With the wort at a temperature of about 25 degrees C an an OG of 1057. I pitched Fermentis S33 yeast (hydrated as per the instructions from Fermentis). That temperature is a few degrees higher than is ideal, but since it was late afternoon I expected it to go down to around 22C during the night (which is close to ideal).

There was a fermentation lag of about 4 hours before CO2 production began. Two hours later CO2 production had already become vigourous. When I got up this morning around 6 fermentation it was downright volcanic, and the temperature of the wort had risen to 28C (obviously due to yeast activity) in spite of the fact that the room temperature had gone down.

When I returned shortly after eleven that morning (say, 4 hours and a bit later) CO2 production had ceased entirely. Not a single bubble has escaped the airlock for the past three hours. Wort temperature has dropped to ambient temperature again. Specific gravity sits at 1030. I could live with 1015, even with 1020 maybe (although I'm aiming for 1013 or thereabouts) and I know that S33 has a rather high final gravity, but 1030 simply won't do.

What gives? Any suggestions on how to proceed? (Other than giving it time, which is the best I can come up with.)

All thoughts on the matter would be appreciated!

// FvW

PS: Yes, I know, S33 might not be the obvious choice for a sweet stout, but I just wanted to try it and see what it does.

 
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Old 02-18-2013, 12:58 PM   #2
RM-MN
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First thing to do is nothing. Second it to read this bit of info. http://www.brewgeeks.com/the-life-cycle-of-yeast.html
The third thing to do is be patient. Check the gravity again in 2 weeks.

 
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Old 02-18-2013, 06:08 PM   #3
day_trippr
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May 2011
Stow, MA
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Unless one's "volcanic" is another's "piffle", I would suspect the measuring technique is off. How was the current SG determined?

Cheers!

 
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Old 02-21-2013, 01:54 PM   #4
frankvw
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Feb 2011
Johannesburg, South Africa
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Quote:
Originally Posted by RM-MN View Post
First thing to do is nothing. Second it to read this bit of info. http://www.brewgeeks.com/the-life-cycle-of-yeast.html
The third thing to do is be patient. Check the gravity again in 2 weeks.
So far I have done nothing, on the basis of the assumption that nothing I can think of will fix the problem so any meddling can only make it worse. I did the reading up you suggested. What I read there makes sense, and matches what I already new (I've inhaled Palmer and other works several times by now). It's just that I've never experienced anything like this before. I'm also not to clear on how the yeast is going to further attenuate my wort from 1030 to the mid-1010's without producing any CO2. There hasn't been a single bubble coming out of the airlock since last Monday.

But I'll give it time. We'll see what happens. If there's no attenuation by the end of next week, I'll rack it into secondary and re-pitch.

// FvW

 
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Old 02-21-2013, 01:57 PM   #5
frankvw
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Feb 2011
Johannesburg, South Africa
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Quote:
Originally Posted by day_trippr View Post
Unless one's "volcanic" is another's "piffle"
When there are no longer any individual bubbles coming out of the airlock but just a steady stream of gas that eventually blows the airlock out of its grommet, that's what I would call "volcanic". Which is what happened here.

Quote:
Originally Posted by day_trippr View Post
I would suspect the measuring technique is off. How was the current SG determined?
Hydrometer. Just like I do with all my other brews.

// FvW

 
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Old 02-21-2013, 02:07 PM   #6
cluckk
 
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I know you say it hasn't had a single bubble since last Monday, but that can only mean it hasn't had one when you have been watching. Give it some time and see. It may still be putting off CO2 and you just haven't been there to actually see it escape.

"A watched pot never boils" and a watched airlock never seems to bubble.
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Old 02-21-2013, 02:21 PM   #7
JLem
 
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What was your recipe? A lot of crystal malts? You mashed high as well, so a 1.013 FG may not be possible. 1.020 should be...unless there is an inordinate amount of crystal malt (or lactose?)
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Old 03-03-2013, 05:18 PM   #8
frankvw
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Feb 2011
Johannesburg, South Africa
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Update:
After having been dead to all intents and purposes for two weeks, late this afternoon the fermentation came back to life. I haven't done anything with it; left the carbuoy sitting there undisturbed. Then, an hour ago, suddenly a "gloop" came from the airlock bubbler. As I write this, it's bubbling away at a rate of about three gloops a minute.

Curiouser and curiouser, said Alice...

 
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Old 06-13-2013, 05:12 PM   #9
Foothiller
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Frankvw, I'm curious whether you have any further updates. I have two small batches (luckily just experiments for comparing some ingredients, so no big loss if something is wrong) in which I have a similar behavior using S-33 yeast: the fermentation seemed to start normally, then the air lock slowed after a few days, the wort became fairly clear, and I thought it was almost done. Then we had some high temperatures last weekend, and these air locks started bubbling again, two weeks after brewing, with the wort cloudy again with fermentation. After about two days of this, the airlock has slowed again and the wort is becoming clear again. The small carboys for these experimental batches have not really supported taking gravity readings during the fermentation.

How did yours turn out? Thanks!

 
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Old 06-18-2013, 08:49 AM   #10
frankvw
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Feb 2011
Johannesburg, South Africa
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Quote:
Originally Posted by Foothiller View Post
Frankvw, I'm curious whether you have any further updates...
Well, the long and the short of it is that after two weeks of apparent non-activity in secondary fermentation, the gravity of the wort had come down from 1030 to 1019. At that point I kegged the beer, pressurizing the keg with a bit of CO2, and I gave it another three weeks. After that the keg pressure had gone up, proof that further fermentation did take place in the keg. More to the point, the beer was fine! It's actually one of my best sweet stouts so far, although the flavour profile of the S33 is not quite right, IMO. I will look for a yeast that fits the style better, but in the meantime I've got a perfecly drinkable beer. At the very least I will redo this under better temperature controlled conditions.

Apparently S33 is rather temperature sensitive, not to say temperamental.

But fear ye not, methinks. :-) If your wort is clear and your gravity within acceptable limits, bottle/keg, mature, and drink. The beer should be fine. If the gravity is still too high, give it some time for more (secondary) fermentation and all should end well.

Cheers 'n beers!

// FvW

 
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