Wish i would have thought about fermcap sooner...

[Rob2010SS]

Lost over a gallon of beer due to the fermentation turning it to foam and blowing it out the blowoff. Nottingham yeast is really chewing through this Imperial stout! Thought about it a day too late but added fermcap to stop the bleeding. At least I won't be losing any more...

Before and after...

 

[day_trippr]

Jeebus...that's a hella hole in your beer right there
Have to say, ime, losing that much wort to blow-off suggests the temperature control might not be locked in to what the wort is actually doing.
Oh - wait - I just realized, that's literally fermenting in The Great Outdoors?

On the upside, what's left is likely nicely fermented out

Cheers!

 

[Rob2010SS]

Yeah I'm super bummed about it. Plus side is I have a 7 gallon uni also full of this beer.

And yes good observation. I don't have a way to cool glass carboys anymore. I lost my ferm chamber a while back. So I brought this outside to cool it off once I got home from work. This loss happened all in one day.

 

[Rob2010SS]

Before yeast kicked in this thing was in my basement sitting at 68 which is what I have my uni set to hold to. When I got home from work it was a hair over 74 so I moved it outside and cooled it back down to 66 assuming it might creep back up a couple of degrees quickly. Then I thought about the fermcap and added it. No more loss and still bubbling like mad.

 

[VikeMan]

Well that sucks.

Recipe for Blowoff
High Gravity √
High Fermentation Temp √
Small Headspace √

 

[Rob2010SS]

Well that sucks.

Recipe for Blowoff
High Gravity √
High Fermentation Temp √
Small Headspace √

Yeah, unfortunately the temp got a little hot. Not too hot for the yeast - high end for notty is 75 - but damn close. I have never had a fermentation generate that much heat on me, to raise it 6-7 degrees. It was sitting comfortably at 68F from time I pitched to the next morning. Then it got a little warm!

Since I'm fermenting half of this in a carboy and half in a unitank with glycol control, I wanted both fermenters to ferment at the same temp. I didn't want the uni to ferment at 60F and have the other at 68-70F. So I chose 68F thinking that my 65F basement would maintain it in the carboy and it's still within range of the yeast. Oh well, live and learn.

For future high gravity beers, I will just plan on using fermcap right from the start to avoid the loss. However, I will say that even on my last imperial stout, I had a very similar problem and it was even temp controlled in a freezer at 64F. Lost quite a bit of volume on that guy too.

On a side note, I think this is the fastest activity I've ever seen from dry yeast! Pitched at 230pm and it had about an inch of krausen 6-7 hours later. I was happy to see that.

 

[VikeMan]

I have never had a fermentation generate that much heat on me, to raise it 6-7 degrees.

I brew a lot of Imperial Stouts and have seen more than 10 degrees above ambient at times. And I normally ferment them at ~ 61F, so that's one cold ferm chamber (freezer).

 

[jddevinn]

Not related to foaming but are you covering it when you sit it outside? UV light (sunlight) is terrible for beer.

 

[Rob2010SS]

I brew a lot of Imperial Stouts and have seen more than 10 degrees above ambient at times. And I normally ferment them at ~ 61F, so that's one cold ferm chamber (freezer).

I guess when it was in the freezer I just never witnessed it get that high. I have the probe taped to the side of the carboy and insulated with towels. The freezer always kept that temp in check but I didn't have a thermowell running into the beer to REALLY know.

 

[Rob2010SS]

Not related to foaming but are you covering it when you sit it outside? UV light (sunlight) is terrible for beer.

I only had it out there at night. During the day it's on my basement in a room that doesn't get light.

 

[day_trippr]

fwiw, I've done extensive testing comparing the readings from a thermowell centered in the middle of a 5.5 gallon batch in a 6.5 gallon carboy vs the same type sensor (ds82b20) pinned to the side of the same carboy under an inch thick ~4x4" pad of closed cell foam. The thermowell tracked within 1°F of the strapped sensor through the entire fermentation, though it lagged "change" (ie: cooling and heating actions took longer to register at the middle of the carboy - as one would expect).

Here's an example showing a couple of chamber heating cycles vs the probe response (right at the precipice of a cold-crash). The thermowell'd probe (green trace) is in Fermentor #1 along with the strapped probe (red trace). The remaining trace is a strapped probe on the second carboy in the same chamber. The lag on the green trace is fairly evident.

Here's a close-up of a few cycles showing the thermowell lag a bit better. Does that matter? At this point I don't think so.

I came to the conclusion that the sanitation risk of a thermowell in a 6.5 gallon carboy vs any appreciable improvement in control wasn't worth it. The thermowell'd probe is still hooked up and running in my primary fermentation fridge but I didn't use it on the batch that's fermenting in there right now. It's just an extra chamber sensor at this point...

Cheers!