Dry hopping restarted fermentation

[Teufelhunde]

5 days ago, I dry hopped a Mosaic IPA that had been in the fermenter for a month. The SG was right where FG was supposed to be at 1.012. There was no evidence of foam on the top or bubbles of any sort.

A couple of days ago, I noticed a couple of bubbles, but didn't pay much attention, figuring out that it was warming up a little (sitting at room temp) and giving up a little gas. When I went in to check on it tonight in preparation for bottling tomorrow, after I took the cover off (trying to keep light off of it), I noticed through the translucent bucket that it appeared that yeast had started flocculation again (streaks down the sides where there were none when I dry hopped). I popped the top for a look, and sure enough, there was a thin (1/8") layer of foam on the top....

I was under the impression that hops would not ferment, but I remembered something I had seen:



The pertinent part starts at 7:39 if it doesn't load at that point. It is discussing diacetyl, but mentions that hop pellet makers have changed their processes, and it is leaving fermentables in the pellets.

I guess I'm gonna find out what this IPA tastes like with a couple of weeks sitting on the dry hops.......

YMMV

Lon

 

[day_trippr]

Welcome to "hop creep".

It's not "fermentables in the pellets", it's hops with enzymes similar to amylase that cause additional fermentation, that in turn can cause undesirable characters. Mosaic may be one of the most active strains in that regard - I have run into the "creep" issue with that one myself...

CHEERS!

 

[ncbrewer]

Interesting - I've never heard of the ALDC enzyme.

 

[PCABrewing]

5 days ago, I dry hopped a Mosaic IPA that had been in the fermenter for a month. The SG was right where FG was supposed to be at 1.012. There was no evidence of foam on the top or bubbles of any sort.

A couple of days ago, I noticed a couple of bubbles, but didn't pay much attention, figuring out that it was warming up a little (sitting at room temp) and giving up a little gas. When I went in to check on it tonight in preparation for bottling tomorrow, after I took the cover off (trying to keep light off of it), I noticed through the translucent bucket that it appeared that yeast had started flocculation again (streaks down the sides where there were none when I dry hopped). I popped the top for a look, and sure enough, there was a thin (1/8") layer of foam on the top....

I was under the impression that hops would not ferment, but I remembered something I had seen:



The pertinent part starts at 7:39 if it doesn't load at that point. It is discussing diacetyl, but mentions that hop pellet makers have changed their processes, and it is leaving fermentables in the pellets.

I guess I'm gonna find out what this IPA tastes like with a couple of weeks sitting on the dry hops.......

YMMV

Lon

I had that happen once a couple years ago. Settled back down after a couple days and the beer turned out as I expected, nothing undesirable. I hadn't taken a gravity reading yet when I added the hops so I don't know if it had hit final or not.
In my case the hops were whole.

Hasn't happened since.

 

[Rob2010SS]

Yep, hop creep. Some people, myself included, have implemented a "soft crash" prior to dry hopping to encourage the yeast to drop out. My understanding is this helps limit or eliminate the hop creep issue as well as some hop burn.

On a side note, you said you're going to let this beer sit on the dry hops for a couple of weeks? Can I ask why? "Studies" have shown that on the smaller homebrew scale, extraction can be completed in 3-4 days or sooner. Any particular reason you're letting it sit for weeks? Too long on dry hops can cause grassy/vegetal flavors as well as more perceived bitterness. Not trying to persuade you to do anything different, just curious is all.

Cheers!

 

[Teufelhunde]

Yep, hop creep. Some people, myself included, have implemented a "soft crash" prior to dry hopping to encourage the yeast to drop out. My understanding is this helps limit or eliminate the hop creep issue as well as some hop burn.

On a side note, you said you're going to let this beer sit on the dry hops for a couple of weeks? Can I ask why? "Studies" have shown that on the smaller homebrew scale, extraction can be completed in 3-4 days or sooner. Any particular reason you're letting it sit for weeks? Too long on dry hops can cause grassy/vegetal flavors as well as more perceived bitterness. Not trying to persuade you to do anything different, just curious is all.

Cheers!

I was planning to leave the hops in, but after 6 days and it was still bubbling, I opened it up and removed them, figuring that the continued fermentation would generate CO2 and drive out the oxygen I let in by opening it up. It bubbled for a few more days, but has finally settled down. Will be bottling as soon as I have a chance...

 

[Teufelhunde]

Well, I bottled this batch today. It tasted OK, but with a pretty harsh alcohol bite. It had fermented from 1.012 down to 1.006 raising the ABV to 8.1. I'm thinking this one is going to need a month or better to mellow out a bit prior to drinking it.

YMMV

Lon

 

[jcryan2]

Is what is seen in these pictures hop creep? I dry hoped an ale with pellet hops (Cascade and Centennial in a mesh bag, which I removed before taking the picture.) for the first time in several years and got a film on the surface. First time I'd seen anything like this. Smelled fine so I kegged it today. I'll let it sit for a bit and give it a taste but am curious if what I have is hop creep or something that trashes the batch.

 

[Teufelhunde]

Is what is seen in these pictures hop creep? I dry hoped an ale with pellet hops (Cascade and Centennial in a mesh bag, which I removed before taking the picture.) for the first time in several years and got a film on the surface. First time I'd seen anything like this. Smelled fine so I kegged it today. I'll let it sit for a bit and give it a taste but am curious if what I have is hop creep or something that trashes the batch.View attachment 770025View attachment 770027

My guess would be hop creep......might want to make sure there is a pressure relief of some sort on that keg unless all of that foam had receded prior to kegging.....

 

[jcryan2]

I kegged it when I took the picture Friday. I have it in a kegarator at 11 lb CO2 at 35 degrees F. I can vent it occasionally. Tasted it today. It is a pale ale I did several years ago. Do not remember it having the high hop bitterness this batch has. Would using pellets (assuming same alpha %) versus leaf push the hoppiness up that much?

 

[Gorm]

I’ve been told that hop particles in a dry hop situation are having a nucleation effect ie yeast attaches to the hop particles thus causing a bit of co2 release or foaming.
I have seen this several times with dryhopping pellets or hop hops. So, I dont really worry about a bit of activity in the airlock or some foam on top of the fermenter.
Now, if some odd looking foam,mold or foul smell starts coming out of the airlock or when one opens the fermenter, I’d suggest contamination by the added hops or otherwise.

 

[Teufelhunde]

I kegged it when I took the picture Friday. I have it in a kegarator at 11 lb CO2 at 35 degrees F. I can vent it occasionally. Tasted it today. It is a pale ale I did several years ago. Do not remember it having the high hop bitterness this batch has. Would using pellets (assuming same alpha %) versus leaf push the hoppiness up that much?

I wouldn't expect that to be the case, but I may be wrong....