Fermentation Restarted after Three Weeks

[Stellanor]

Been looking through the forum and can't find a sitch exactly like this one, so I figured it couldn't hurt to ask for some advice.

About a month ago, I decided to try making the White House Honey Ale (recipe here: http://www.whitehouse.gov/blog/2012/09/01/ale-chief-white-house-beer-recipe). Followed the recipe exactly, and OG was right in line with what others have gotten with 1.067. Pitched yeast and had what I thought was a standard primary fermentation. Got a huge, beautiful krausen right off the bat and after 7 days in the primary, activity had ceased and I racked into secondary. The gravity after the first 7 days was 1.020, and she spent two additional weeks in secondary (three weeks total).

On the 21st day, she looked exactly the way she did going in. No activity at all except for a little clarification and sediment formation. I took another gravity reading and it hadn't budged from 1.020. Since batches that contain extract can finish a little on the high side, I decided this was nothing out of the ordinary and to bottle the next day. Lo and behold, when I woke up I saw the airlock bubbling vigorously. Took a gravity reading that day, and it looked like it hadn't moved, but I decided to wait a bit. By the following day, another little baby layer (krausen and CO2) had formed (about 1/2" thick) and I've got what looks like streams of champagne bubbles coming up from the bottom of the secondary forming this 1/2" layer of bubbles on the surface of the liquid. Took another gravity reading on the 26th day, and I think my mind is starting to play tricks on me. It looks like the gravity is going down, but VERY slowly, but still very close to 1.020. I'd hate to bottle at this point because it's clearly got gas coming up enough to keep the airlock steadily bubbling. I don't think I have an infection, just a little layer of tiny CO2 bubbles that aren't ceasing to rise from the bottom (I read every post in the Post your Infection thread and this isn't anything like that). We're now almost four weeks from brew day. Has this happened to anyone else? How long did it take to peter out? Would it be helpful to swirl the fermentor to speed the process along to give it more contact?

 

[jbaysurfer]

I'm guessing you stirred the yeast when you took your sample and maybe temperatures rose a bit (or not) in the fermenter, causing a little bit of an increase in action. A picture would be helpful, but if you're 21 days in, it's likely done fermenting, may as well leave it another week to be sure, but I'm sure you're safe to bottle. Sometimes C02 bubbles releasing is just from temperature changes. Also, yeast can clean up after themselves, eating some of their own byproduct, but not neccesarily the low levels of sugars that remain.
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How'd the samples taste?

 

[Heavywalker]

So it has been at or near 1.02 or so close that it is not noticeably going down on the Hydro?

I'd say you are safe to bottle, but you could always wait until it stops bubbling to ease your fears.

Did you move your fermenter prior to this new activity?

Has the beer possibly warmed up slightly over the last several days causing it to off gas?

 

[Stellanor]

Thanks, guys! Definitely more gentle in appearance than what is normally expected with "primary" fermentation. It both smelled and tasted great after the last hydro test, though just a teeny bit sweet (probably from the 1.020).

Haven't done a test again since the last one (about four days ago). Just been letting the bubbles rise (and was praying for them to stop!). Temperatures have been pretty steady, 68F +/- maybe 1 or 2 degrees and I try to keep the secondary insulated, and absolutely no internal temperature rise of the fermentor itself (like you'd see during primary). No movement of the fermentor except the brief sampling after the first two weeks in the secondary.

Will post a picture when I get home. The "krausen" doesn't look like normal krausen except in one blobby spot. Looks more like a cake. Heh.

 

[Ryfi]

It sounds like off gassing to me since the FG isn't changing or isn't drastically changing. Off gassing can occur when temps and barometric pressure change.

 

[Stellanor]

Here are some photos of the layer of small bubbles that has formed on the liquid surface. Sorry for the large size. In the first one, you can actually see the small CO2 bubbles rising to join their tiny brethren. Airlock still bubbling away, end of day four.

 

[boydster]

I had that happen with a batch once, using S-33 for the first time. Let it go until the zombie krausen is gone and the beer drops clear again. You'll probably drop another 3-5 points.

 

[jbaysurfer]

Yeah, that's perfectly healthy looking krausen. I like Boyd's term: Zombie Krausen.

 

[flars]

Let your next brew go for 14 days before you take a SG reading. You got lucky on this one. Enough yeast was transferred to the secondary to finish the fermentation.

 

[Stellanor]

...Let it go until the zombie krausen is gone and the beer drops clear again...

Love it. Call Frank Darabont. Walking Dead Beer.

Will do about the patience. I am far too wound up about this one after this! Thanks everyone!

 

[wdautrem]

That is weird. I'm seeing the same thing from that same recipe. Did a yeast starter, had a strong primary with a blow off in less than 12 hours. Was done bubbling the air lock in about a week, but left it in the primary because I could see it was still dropping out. At 2 weeks moved to secondary, air lock was dead still for 2 more weeks while the beer settled. I was getting ready to transfer to a keg this weekend and noticed a ring of small bubbles and the airlock is now burping once a minute or so. It has not been moved, stirred, exposed to light or changed temp (71 degrees) since I transferred.