IPA cleared, then got active again


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Feb 6, 2013
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Total noob here, and I've got a question that I can't seem to find an answer to. Brewed a 2.5 gallon batch of IPA a little over 2 weeks ago, 1/21 to be exact. Had some really active fermentation for a few days and then it began to clear pretty nicely. However, on 2/2 (nearly 2 weeks in fermenter), the yeast started getting really active again and I got another foam head of bout 1/4" to 1/2". It's a partial extract batch (was shooting for DIPA but came up short on OG so it'll probably be closer to standard IPA) and has quite a bit of malt for a 2.5 G volume. I was allowing some bottles to carb in the same closet (68-70 F) so is it possible that the yeast kind of settled into the trub and that when I moved the carboy a bit to move my bottles, it "woke up" the yeast? It stayed pretty active until this morning, when the foam head had all but disappeared again. I'm totally fine sticking with the "when it's ready, it's ready," but I've just not experiences such a dramatic reactivation of yeast after a couple weeks. Again, noob.
Yeah, you probably stirred up the yeast. Smell and taste before bottling to make sure it wasn't some wild bacteria. I bet you are fine.
Thanks, I appreciate the input. And you confirmed my suspicions, so I like thinking that I was right. Are there drawbacks to pitching too much yeast and could that have been an issue?
Moving a fermenter or raising the temperature will cause CO2 to come out of solution creating airlock activity and may look like a second fermentation. This doesn't explain new krausen formation. I would certainly taste it in case of infection.
"I would certainly taste it in case of infection".

Yes tasting is just one of those things brewers must do to ensure a quality product. :D
Took a sample last night to check gravity and it's sitting at 1.014, so I then tasted the sample and it's pretty good. Of course, that's a relative term since it's warm and flat, but had good bitterness and balance and certainly no off flavors. I plan on dry hopping it soon too, which will add the aroma that's missing. Shifting it around last night released some CO2, but the earlier phenomenon I mentioned looked like a full-on early fermentation. I mean, the bubbles were rising from the trub and gathering at the top to create a foam head; not nearly as active as the first go-round, but pretty significant. Given that it was a partial extract brew and a small batch, I was wondering if it's possible that some of the yeast sort of got buried in there and then woke up due to some shifting and temp changes. We had had unseasonably warm temps for a few days, then snapped right back to single digits, which would have caused the furnace to kick up extra high in the house, so it's possible that the temp in my fermentation closet jumped.
Have any of you ever dealt with infection before? I know it's like the boogeyman for noobs, but my understanding is that if you properly sanitize, you almost have to try to get an infection. Either way, the sample tasted good, no off smells or tastes, and it's starting to clear again.
If you dry hop for a few days, that will give it time to finish completely but it sounds like you are near the FG. You probably just roused it, or maybe a temperature change kicked it into high gear. Hard to say for sure.

As for infections, I have to admit, I had one in 2011. Hadn't had an infection in years, and only the second in my life, but I was pushing the limits of repitching and lazy cleaning practices - it was a good learning experience. Tasted like soapy rancid dishwater, yuck! You went with brand new yeast and it tastes good so you are double fine.

Here is a write up on what I uncovered with the infected batch:
http://www.brewersfriend.com/2011/11/12 ... forensics/
Glad to hear that it tastes good. Could have just been some temperature fluctuation. If the yeast gets started, and the temperature drops, some may drop out, stalling the process. When it warms up the remaining yeast will kick in again. Do the best you can to keep fermentation temperatures stable and at the cool end of the yeast tolerance, at least through the growth stage of the ferment. After a couple of days of vigorous fermentation, you can ramp up the temperature a few degrees to keep the yeast going strong. Remember cool fermentations take more time to complete, and the lag time from pitch to activity can also be extended. Don't worry about lag time. The yeast are working in there, you just cant see it.

As far as infection goes, with proper practices they are a rarity. One worry is that for new brewers, an infected batch becomes an expensive 5 gallon waste of time, and could discourage them from continuing. We want more brewers making better beer.
chessking said:
As far as infection goes, with proper practices they are a rarity. One worry is that for new brewers, an infected batch becomes an expensive 5 gallon waste of time, and could discourage them from continuing. We want more brewers making better beer.

+1 It doesn't hurt to be extra paranoid about sanitization, especially when starting out. Just be careful of getting too lax.