Brewing in an oversized fermentor

[jdahl10]

I did a brew on Saturday, due to some miscalculations and mismeasurements, I ended up with 3.5 gallons of post-boil wort. I pitched a full packet of rehydrated yeast in a 6.5 gallon bucket anyway. Four days later, the airlock is still pretty inactive. There is condensation on the inside, but it isn't bubbling audibly.

Is this because of all the excess space in the fermentor or did I kill my yeast? I'm going to open it up and test the gravity if it still isn't bubbling tomorrow, should I have a packet of yeast ready to pitch to try for round 2?

 

[sheepcat]

The only real issue you might encounter with a plus size bucket is oxygenation.

Was the 3.5 gallons an appropriate gravity? I mean, did you boil off too much water, or did you not get enough wort to make five gallons post-boil?

Did you aerate the wort? Lack of oxygen can cause a slow start and sluggish fermentation.

 

[jdahl10]

I boiled off too much. I shook it up but maybe it didn't aerate enough? Also I opened it last night and there was no kraussen at all so I think I should repitch some yeast

 

[GilSwillBasementBrews]

If you boiled off too much you can always just add more water to bring to the appropriate volume intended.

 

[RM-MN]

I boiled off too much. I shook it up but maybe it didn't aerate enough? Also I opened it last night and there was no kraussen at all so I think I should repitch some yeast[/QUOTE]

I don't think so. Many time an ale yeast will rip through the sugars in 2-3 days at which point it quits giving off CO2 so the airlock stops bubbling. The best thing to do with this batch is to put it somewhere you can't see it and quit worrying about it for a couple weeks.:rockin:

Have a quick read about how brewing yeast works. http://www.brewgeeks.com/the-life-cycle-of-yeast.html

 

[sheepcat]

Since you boiled off too much, you can always just add water back in. It could be the SG of your wort is too high and the yeast is struggling.

If that doesn't work and you still don't see anything by now, I'd repitch.

 

[Aristotelian]

I don't think so. Many time an ale yeast will rip through the sugars in 2-3 days at which point it quits giving off CO2 so the airlock stops bubbling. The best thing to do with this batch is to put it somewhere you can't see it and quit worrying about it for a couple weeks.:rockin:

Have a quick read about how brewing yeast works. http://www.brewgeeks.com/the-life-cycle-of-yeast.html

I would be worried with no airlock activity after 4 days. He could take a gravity reading to confirm that no fermentation has taken place. If that is the case, he needs to repitch.

 

[jdahl10]

Checked the gravity and it's actually bellow my target FG! Crisis averted

 

[MagicMatt]

Which means you have another issue to worry about: your bucket has a leak. The fact that there was no airlock activity is a big indicator of this. Time to find that bad seal!

 

[Froyd]

For the past 11 years, I have used a 6 gallon fermenter from Coopers that has a clear lid, allowing me to monitor fermentation. Of course, the lid is ported and I use an S airlock. My batches are usually round 4.5 gallons, so there's usually lots of head space, and the airlock seldom sees any activity. My guess is that: a) the air escapes through the airlock but infrequently enough that I rarely see it bubble; b) the bucket seals leak (but I can barely twist off the lid at the end of fermentation because the rubber gasket grips so powerfully); and/or c) the head space is big enough that there's far less need for the fermentation gasses to escape anywhere.

If it weren't for the clear lid, I would have worried all these years about weak or nonexistent airlock activity, but fortunately within 12h of pitching, I have always been able to witness foam building on my worth and fermentation activity developing over the course of a few days.
I have screwed up brews in the past, but the causes were always pretty obvious and not related to the bubbling activity or lack thereof of the airlock.

 

[MagicMatt]

Head space has little effect on airlock activity. I've used a 5 gallon glass carboy for a 2 gallon batch and during high krausen the airlock bubbles about once every 2 seconds. It doesn't take much positive pressure to push up the airlock, but gas will always find the path of least resistance (which is usually a leak). For primary fermentation a leaky bucket is probably still OK as there is enough off-gassing to prevent anything from getting in, but I wouldn't keep the beer in there for much longer than a week or so due to the possibility that once fermentation slows, air could creep in and oxidize the beer.

 

[RM-MN]

Head space has little effect on airlock activity. I've used a 5 gallon glass carboy for a 2 gallon batch and during high krausen the airlock bubbles about once every 2 seconds. It doesn't take much positive pressure to push up the airlock, but gas will always find the path of least resistance (which is usually a leak). For primary fermentation a leaky bucket is probably still OK as there is enough off-gassing to prevent anything from getting in, but I wouldn't keep the beer in there for much longer than a week or so due to the possibility that once fermentation slows, air could creep in and oxidize the beer.

You mean to tell me that I shouldn't have left my beer in that bucket with the leaky lid for the 9 weeks? Turned out to be one of the better beers.

The leaky lid isn't a problem because the beer dissolves a lot of CO2 during fermentation and that CO2 outgasses for quite a while. During that time there won't be any bacteria getting in because they can't swim against the current of the CO2 escaping.

 

[MagicMatt]

For most beers, after a week or two there's not much off gassing from the beer, certainly not a "current" enough to stop oxygen from diffusing in if the leak is substaintial. I'm sure many a homebrewer has a higher threshold for oxygen exposure than I do, but I want to do everything I can to minimize the risk.