Recovering from a Stalled Fermentation

[goteeguy]

Hi everyone,

I'm currently brewing a Muntons Red Ale kit with additions of 1kg Dextrose and 1lb DME. OG was 1.040 with an expected FG of 1.008. I pitched the included dry yeast and fermented at 22°C in a sealed, air tight brew bucket. Fermentation was strong for 3 days then stopped. No bubbles in the air lock.

A week later, I checked the SG. It had dropped to 1.012 - a little short of expected - so I roused the yeast by gently (but thoroughly) mixing the trub back into the beer. After sealing the lid, bubbles immediately started (approx. every 30 seconds) and have continued for the past 8 days without slowing. (I suspect the sudden lack of activity may have been caused by an unexpected drop in ambient temp due to some freakishly cool days, or perhaps the yeast was under pitched.) I checked the SG again last night and found it had dropped to 1.010. It seems the yeast are indeed still active (albeit slow), so I have now moved the beer to a warmer location (25.7°C) where I hope to encourage them to finish their work a bit quicker.

After doing more reading online (probably my greatest fault is reading & analyzing too much), I'm now doubting whether the beer IS actually continuing to ferment, or whether the slight drop in SG could be attributed to off gassing or some other mystic forces at work. I'm just concerned, as the airlock continues to bubble at regular 30 second intervals without any hint of slowing down. With such activity, I would usually expect to see a greater drop in SG over 8 days than just .002 points. Am I wrong to assume this?

The beer has been in primary for 4 weeks now, and I had hoped to bottle on the weekend. Unfortunately, even if the fermentation does stop, the beer has not yet fallen clear since I stirred the trub back up - so I expect I'll be waiting another week or two for that to happen (unless I use finings).

I'm not concerned with off flavours, and am quite happy to let the brew sit in primary for as long as needed. I'm just not sure what to do at this point.

Any advice would be greatly appreciated.

Cheers!

 

[mashinary]

Bubbles aren't always a sign of fermentation. Some times it's just co2 coming out of solution.

 

[Rob2010SS]

Soooooo, I wouldn't necessarily have shaken it up, but there's no going back now. That risks oxidation of the beer at this point. What I would tell you to do is to let it sit for 3 days, take another gravity reading, sit for 3 more days and take another gravity reading. If the next two gravity readings come out at 1.010, you're done.

As mashinary said, bubbles are not a reliable sign of fermentation. The bubbles can stop and you'll still be fermenting. Gravity readings are the only sure fire way to know when you're done.

 

[goteeguy]

Thanks for the replies. I understand bubbles don't necessarily correlate to fermentation, which is why I've been using my hydrometer. I'm just surprised that with the amount of bubbling that's going on there has only been a slight drop in SG. I'll check SG in 3 days as suggested and see what I find.

The reason I gently stirred the yeast back into the beer was based on recommendations in numerous other threads. I'm not too concerned about oxidization - my palette isn't that refined to notice - and it seemed the simplest action to take (other than no action at all). I will, however, be impacted by having to wait longer for the beer to clarify again.

Daddy wants a drink!!!

 

[flars]

I don't think you did anything to damage your beer. Rousing the yeast and warming the beer will encourage the yeast to finish. Take another SG reading when you see the beer start to clear. An extra one or two weeks in the primary is not a problem as long as CO2 is being produced or just coming out of solution.

 

[goteeguy]

Thanks, flars. I was beginning to worry I screwed up this batch and was on my way to making vinegar. LOL! (I like vinegar, but not THAT much!) I'm on holidays this week, so will check the SG at the end of the week and go from there. Cheers!

 

[goteeguy]

Update: My airlock activity has finally subsided (after 5wks) - only a bubble every hour or two. I took a sample which showed a SG of 1.008 (right on target). However, I then remembered reading on the forum that samples should be degassed prior to taking hydrometer readings, so I shook it until no bubbles were produced. It now reads at 1.004 - significantly lower than expected for Muntons kit yeast.

I have confirmed the calibration of my hydrometer and also adjusted for temp. The beer tasted warm and flat, but beyond that I noticed no off tastes (so don't expect any infections). If anything, the beer was maltier that expected; sweet at the front of the mouth, but a little bitter at the back. I suspect it should mellow in the bottle. It was also VERY cloudy.

I've racked to secondary and added 1tsp of gelatin mixed with 1 cup of water to speed clarification. I'm hoping to bottle after 7 days and will allow to condition for 3wks prior to drinking.

Fingers crossed.