Hop Creep Second Fermentation?

[jeffceo24]

I brewed an IPA (OG was 1.061-1.062) used Cellar Science Cali Dry Yeast and have been fermenting at 67 degrees in a mini fridge. Fermentation took off and was vigorous. I used a blow off tube because an airlock wont fit in the fridge, it was bubbling constantly for 2-3 days. Beer cleared up and seemed to finish activity after about 4 days or so.

I dry hopped 4 days ago with 2oz Simcoe and 1oz Citra. Yesterday was exactly 3 weeks in the fermenter. I started hearing the blow off tube bubbling and figured it was just co2 offgassing from introducing the hops. However, when I inspected the carboy, the beer appeared to be fermenting again. I was going to keg it today but now I am worried about diacetyl or off flavors if it is actually fermenting again. FYI there is a lot of traub from the kettle because my bazooka screen got messed up. Any suggestions?

 

[eric19312]

I see your temperature gauge says 73F. If your beer warmed up from 67F to 73F it would be normal for some CO2 to come out of solution.

 

[ReaperOnefour]

Go ahead & keg it. You should be fine. 3 weeks in primary is more than enough time to ferment. I always ferment for two weeks. When i dry hop i add the hops on day 9 or 10, then i bottle.

 

[TheBrewingDutchman]

Well, normally you would take regular gravity readings towards the end of fermentation. If the gravity stays the same for two, three days in a row you can safely assume fermentation has finished. Don't try to 'read' the air lock.

Now, hop creep is a slow process and you wouldn't notice it immediately. If it occurs, then expect it to have an effect over a some weeks, maybe months.
Example: if your FG was expected to be 1.010 at the end of fermentation, you reached that and you held it for two days in a row. Then you bottle the beer (I know you keg, but bear with me here). You add priming sugar for conditioning. You leave the bottled beer for a couple of weeks and all the time the hop creep has free range. Over time your beer's gravity drops to 1.009 or even lower (I've heard of hop creep taking 3 or 4 extra gravity points, which is a lot). That means that fermentation continues as the yeast ferments the priming sugar, but the enzymes from the hops also transform non-fermentable sugars into fermentable sugars. What happens now is that your beer ferments further without you knowing and it creates a lot of CO2 that can go nowhere. Your bottles slowly become beer bombs. The hop creep ghost.. The best thing that can happen to you is you looking for a mob on a long stick and for words to explain what happened to your better half. The worst that can happen is something I don't even want to think about.

Now, with kegging it's much less dramatic than with bottles. You don't use as much priming sugar and usually good pressure valves prevent overpressure incidents. And you brewed an IPA which is best to drink as young and fresh as possible. Hop creep won't catch you off guard that easily – the beer's likely gone by the time the hop creep would start to become an issue. Or, it should be gone by that time.

But do make sure you do your regular gravity readings to know if fermentation has finished. Or get a tilt, ispindel or something like that to help you monitor it. But, these likely won't go through your carboy's neck, I'm affraid. Then a plastic or stainless steel fermentation bucket would be the answer. Much easier to clean, too, than you carboy. I'm so done with carboys... really, no clue who ever thought those would be a good idea to use for homebrewing, but the day I had the epiphany to ditch mine was a glorious one...

Anyways, always remember: measuring is knowing...