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Unexpected Continued Fermentation

bobo1898

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I brewed a beer back in September, hoping to have it ready for Thanksgiving. It sat in primary for two weeks. Did two gravity tests (three days apart) and concluded that I reached FG. I racked over to secondary for further conditioning and clarity. Everything appeared normal--pretty dull appearance in the carboy.

After three weeks in secondary, I've suddenly gotten what appears to be active/further fermentation. For the three weeks, there was no activity and then suddenly, a week and a half ago, there is activity on the surface. You can see in the attached picture and video (you have to download it to see it) the activity that is present.

I searched some forums for this and found that the beer is just off-gasing CO2 and that it's nothing to worry about. Shouldn't I be concerned about bottling this? When it started showing this activity, I waited about three or four days, hoping for it to subside and it didn't. So I decided to take a gravity test. The gravity is still at my FG that I recorded over a month ago so it doesn't appear to be going through anything (and it tastes fine). My next concern was that it was infected (even though I'm fairly thorough in sanitation) but there doesn't appear to be any mold--even a week and a half later. What you see on the surface are bubbles.

I'm using Wyeast London Ale. I've brewed this beer before and have never had this issue. Actually, I've never seen it in any other beer I've made over the last nine years.

Do I wait it out still? Is this not out of the ordinary? You can see in the video, that it's still pretty active. It's been the same since I noticed it. No real signs of dying down.

 

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Did the carboy get jostled? Was there a temperature increase? Those could both lead to CO2 coming out of solution.

Do you have an airlock in place? If so you could replace it with a solid stopper to hold in the pressure. At some point the pressure would build up enough to keep the CO2 from coming out of solution. If that pressure is low enough that it doesn't blow out your stopper then it probably isn't a big deal and wouldn't cause your bottles to blow.

You could cut back a bit on your priming sugar if you are worried about over carbonation.

--GF
 
Thanks for the reply, Giga.

I did move it over, maybe two feet, to make room for another vessel. There was no temp change. With that happening, I figured that it would subside by now, no?

I do have an airlock on but don't have a solid stopper.

So what you're saying is that this can happen and my moving of the carboy is most likely the culprit?
 
GigaFemto said:
Yeah, that is my semi-educated guess.

--GF

It can happen, It could also happen if he went up in temperature and restarted the fermentation that way.
 
Greetings bobo - a couple things come to mind.  First, what was the projected FG and what was the measured FG?  Next, what are you using to test the gravity?  I don?t believe this phenomenon is CO2 gas being released from the beer - there?s simply way too much Kraeusen for that.  Also, what did you use for your secondary fermentation vessel?  Years ago I used a plastic bucket and nearly every batch of beer was getting infected.  I finally dumped the bucket and began using fermenter made from PET.

I also don?t believe moving the fermenter or the fermenters ambient temperature is causing this issue.

So, my gut feeling is you have an issue with either your SG measuring device or the method in which you?re using this device.

Thoughts??
 
Another possibility is that the yeast fell down before they had finished consuming all the sugars (some strains are prone to do this), and when you moved the carboy you stirred them up and they came out of hibernation and began fermenting again. Gravity measurements would tell you if this is the case.

--GF
 
Thanks for the response!

KellerBrauer said:
First, what was the projected FG and what was the measured FG? Next, what are you using to test the gravity?

The projected final gravity was 1.016. When I've made it in the past, it's gone as far as 1.013. This time the FG was 1.018. I'm using a hydrometer to measure it. In distilled water, my hydrometer is 1.000. I have four other batches next to it and those all seem to be okay.

KellerBrauer said:
Also, what did you use for your secondary fermentation vessel?

I don't use plastic buckets. All my fermenters are glass carboys. I clean these immediately after use with a bottle brush and hot water for the stuff caked on. Then I follow this up with soap and hot water.

KellerBrauer said:
I also don?t believe moving the fermenter or the fermenters ambient temperature is causing this issue.

I suppose that there's a possibility the temperature changed, but maybe 1 degree. My batches are all right next to each other. I also feel that it's too much kreusen. I'm a bit more concerned because there are now large bubbles on the surface--you can see in the attached photo. Like I said, when I tasted it after a week or so (from when this started), it seemed no different than it did a month prior--and the gravity didn't move.

GigaFemto said:
Another possibility is that the yeast fell down before they had finished consuming all the sugars (some strains are prone to do this), and when you moved the carboy you stirred them up and they came out of hibernation and began fermenting again. Gravity measurements would tell you if this is the case.

Definitely hoping it's this, GF. I'll do another gravity reading at the end of the week and see what's happening.

 
Another thing of note from this batch.

When adding minerals/salts to the strike water, calcium chloride was somehow mistaken for calcium carbonate (chalk). This mistake was noticed 30 minutes into the mash and the proper calcium chloride was mixed into the mash. pH before the mistake was realized was fine.

Again, it smells good and tastes fine. Not sure if that gaffe could contribute to the problem.
 
Greetings - it sounds to me like you?ve done everything right....with exception to the added salts issue.  So, let it run its coarse and see what happens.  You will know if something is wrong when you are ready to enjoy.  If it smells or taste bad, dump it and make another.

An odd think happened to the brew I have fermenting now.  The first 4 days of fermentation were perfectly normal; 1? kraeusen, steady temperature, constant bubbles through the airlock. All is good.  On the 5th day, suddenly the kraeusen layer quadrupled and is thicker and creamier looking.  Out of nowhere this happens.  Go figure.....
 
Thanks Keller!

Yeah I suppose I'll wait some more, but I probably shouldn't bottle this til the activity subsides, right? I mean ultimately, it's been in secondary for almost a month at this point.

KellerBrauer said:
An odd think happened to the brew I have fermenting now.  The first 4 days of fermentation were perfectly normal; 1? kraeusen, steady temperature, constant bubbles through the airlock. All is good.  On the 5th day, suddenly the kraeusen layer quadrupled and is thicker and creamier looking.  Out of nowhere this happens.  Go figure.....

Sounds like a true top cropper! Better harvest that!
 
I've had similar experiences with changing effects on top of the fermenting wort. I often have bubbles and film which looks like the picture the OP posted.
Barring any sign of infection, I wouldn't be overly concerned with the visual. As with any living organism, yeast can sometimes behave unpredictably.
At the end of fermentation I bump a couple of degrees and take a couple of readings 3 days apart, allowing the beer to finish out.
The main concern is stable readings that matches your target FG. If it seems to have stalled out, bump the heat.
Particularly with low flocculating yeast, I've had beer finish out with muck on the top. A good cold crash will take care of it.
 
Thank Baron!

I will have patience.

Baron Von MunchKrausen said:
If it seems to have stalled out, bump the heat.

I don't exactly have a method for this. The space where I ferment is steady in temperature. Is there a recommendation for this if I don't have control?

Baron Von MunchKrausen said:
A good cold crash will take care of it.

This I can do with it being 30-40 degrees in my garage!
 
bobo1898 said:
Baron Von MunchKrausen said:
If it seems to have stalled out, bump the heat.

I don't exactly have a method for this. The space where I ferment is steady in temperature. Is there a recommendation for this if I don't have control?

An enclosed space (like a closet) is common with a small inexpensive ceramic heater
You don't need much heat to bump 2-3 degrees, so you will need to watch it with a thermometer or temp strip.
Oh.... And don't entirely close the door! You want a gradual temp rise.
 
Space heater seems to be working. Temp was 66ish and now it's around 68/70. Gravity dropped to about 1.013/1.014. Bubbles are dissipating so it seems to be finishing out. I may push it to 72.

This is great because I've had two other beers in primary for three weeks and they aren't done (I need to bottle them by Tuesday). Hopefully the heater will help move things along.

Thanks guys, for all your help!
 
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