Restarted Fermentation?

Hi All:

I brewed the recipe below that I swiped off this forum. It's basically my wife's favorite beer. After three days of fermentation, it died down really quickly. I noticed only a bubble every couple minutes. I left it on the yeast cake for a while to clean up and planned to finish up as the recipe called.

But earlier this week, fermentation started right back up again! Now it's going pretty strong--like a bubble every 15 seconds. Is this normal for this yeast? I will say that the house temp dropped to around 68º during that time, and now it's around 74º.

Anyway, I'm keen to hear what your thoughts are. I'm on schedule to lager it this weekend, but if it's still fermenting...

--Cheers, Chris

SG 1.078
FG 1.006
IBU: 58


Grain/Extract/Sugar
--------------------------------
10.75 lbs. Belgian Pilsner
2.00 lbs. Beet Sugar


Hops
-------------------------------------

.75 oz Columbus 60 min.--> 16.4 AA
.35 oz.Columbus 20 min.
1.25 oz.Czech Saaz 7 min.
.75 oz. Cascade Dry Hop

Yeast
-----
White Labs WLP550

<Mash Temps >
143.6 ºF >>20min
154.4 ºF >>70min


Pitching temp>75 ºF

Lager 3 weeks> (while dry hopping)
35.6 ºF

Warmth = expansion.

Airlock activity does not fermentation determine.

Gravity readings you must take.

Likely the beer warmed up, got bigger, and took up more room in fermentor.

Temperature swings or even barametric pressure swings can make the airlock bubble.

Just remember that an airlock doesn't measure fermentation. It's just an airlock. Only a hydrometer can measure the effects of fermentation.

There's a great YouTube video of an empty carboy with the airlock bubbling away. I don't think fermentation restarted in that empty carboy either

Hi there:

I pulled a reading last night and I was at 1.020--much higher than the 1.006 goal. So it has a LONG way to go. Should I be concerned that it has been fermenting for a week and looks to have a least a week to go and what could be some of the ramifications for this? Could this have occurred because I did not use a starter?

--Cheers, Chris

chrisfiac said:

Hi there:

I pulled a reading last night and I was at 1.020--much higher than the 1.006 goal. So it has a LONG way to go. Should I be concerned that it has been fermenting for a week and looks to have a least a week to go and what could be some of the ramifications for this? Could this have occurred because I did not use a starter?

--Cheers, Chris

Click to expand...

Keep the temperature warmer for a bit and rouse the yeast up. Seeing though this was an AG recipe, what temperature did you mash at and did you use a calibrated and accurate thermometer? If you mashed at too high a temperature you may have a less fermentable wort meaning you may not completely reach the desired FG. In addition, if you did not make a starter, poorly aerated and had a less than ideal fermentation then, yes, this can cause the yeast to not fully attenuate.

Hi there:

I followed the mash temps below exactly and it was measured on a digital thermometer.

<Mash Temps >
143.6 ºF >>20min
154.4 ºF >>70min

There was no starter; I just dumped the vial right in. Henceforth, a starter will be made. How do I rouse the yeast up? Do I give it a good stir? It's fermenting quite well now based on the bubble activity. I look forward to the response!

--Cheers

chrisfiac said:

Hi there:

I followed the mash temps below exactly and it was measured on a digital thermometer.

<Mash Temps >
143.6 ºF >>20min
154.4 ºF >>70min

There was no starter; I just dumped the vial right in. Henceforth, a starter will be made. How do I rouse the yeast up? Do I give it a good stir? It's fermenting quite well now based on the bubble activity. I look forward to the response!

--Cheers

Click to expand...

Don't stir just agitate the vessel a bit to rouse things up. Bubbles don't mean anything other than gasses escaping so give it a few more days and then take a reading, if the gravity has dropped than give it some more time and hopefully it will finish up.

BTW, just because the thermometer is digital doesn't means its accurate, you should still check it in both boiling water and ice water

Hi:

When the water was at a rolling boil, the thermometer was at 212*, so I'm thinking it's on point. I just gave the carboy a good swirl and that seemed to do some good. Quick question, though: when the fermentation stalled, was it in the clean-up phase? Or does clean-up occur after the fermentation slows?

So should I anticipate any off flavors from this batch due to the stalled fermentation?

--Thanks, Chris