Refermentation at 30F and 14 psi

[specialkayme]

I'm brewing my first Milkshake IPA with lactose and strawberries. Went into the conical at 1.060. 66 deg F. 5 days later it dropped to 1.035. Dry hopped for 3 days, SG didn't move. I ramped up to 72 deg F for 2 days, dropped to 1.032. Dropped the temp to 50 deg F for 3 days while I did a second dry hop. SG stayed at 1.032. So I cold crashed down to 30F and hooked up the carb stone to finish it off before transferring it to the keg. Set the regulator to ~12 psi.

Woke up this morning and the conical was covered in beersicles. All over the floor too. Looks like one of the O-Rings on the top was leaking. Pressure was at 15 psi (and looks like the safety valve blew at some point too). Popped the lid and there is crazy krausen going on. Released the pressure manifold and put back the blow off tube, and it's belching like mad. I set the chamber to 34 deg F (to melt the beersicles mainly).

I'm confused as all get out. Why would the yeast refuse to continue fermenting at 66, 72, and 50 deg F, but suddenly wake up with a vengeance at 30 deg F AND under pressure?

 

[brewpharm Hill]

How much lactose did you use and what were your mash temps? Also, what yeast?

My thoughts: lactose and high mash temps are going to give you less fermentable sugars, especially when both are being used. If you're using a low attenuating yeast that could do it as well.


The foam you're seeing could just be off gassing of CO2 from the sudden pressure release. I don't know of any yeast that will have that kind of activity at such low temps. I'm not sure what could have caused the increased PSI reading other than something malfunctioning with your pressure gauge or the wort expanded when it froze and created a smaller head space therefore resulting in a greater pressure reading (beer is mostly water and water expands when frozen).

 

[Hayden123982]

Looking at the photo, it looks super yeasty, but is it really just beer foam that froze? I'd check a gravity and if it did drop then maybe something strange did happen... maybe the higher pressure influenced something's ability to ferment cold

 

[Vale71]

If the beer started to freeze then CO2 would be released as ice cannot hold CO2. You're probably just mistaking that release for continued fermentation.

 

[specialkayme]

How much lactose did you use and what were your mash temps? Also, what yeast?

1.6 lbs of lactose (although I think something slightly less actually got dissolved, I think some ended up in the kettle trub).
157 Mash for 60 min, followed by a mash out.
Wyeast 1318 yeast

My thoughts: lactose and high mash temps are going to give you less fermentable sugars, especially when both are being used.

Target FG was 1.026. Ending up at 1.032 isn't outside the realm of natural possibilities, depending on the health of the yeast, attenuation, and fermentable sugars. So that alone didn't shock me, which gave me enough comfort to cold crash.

I let the carboy sit for 12 hours to naturally "off gas", at 34 degrees (to dissolve whatever ice had formed). I then took a gravity reading, which came in at 1.033, which showed I didn't have a decrease in SG or any apparent signs of fermentation.

If the beer started to freeze then CO2 would be released as ice cannot hold CO2. You're probably just mistaking that release for continued fermentation.

I think you're right.

From what I can tell, a few things happened, mainly errors on my end:
1. Every other beer that I cold crashed to below 32 deg had 5%+ ABV. This one is clocking in at ~3.5%, which means I likely had some freezing issues.
2. I most likely overcarbed the beer. I was shooting for 12 psi. On a 30 deg beer, that was too much.
3. It looks like my regulator might not be as accurate as it once was. Even though my regulator was set at 12 psi, it was likely pushing more than that.
4. The PRV on the conical most likely released, and most likely more than once.
5. I had a small leak on the o-ring on the top triclamp. Again, likely do to the high pressure.

The regulator/leak/prv issue resulted in the CO2 tank draining empty overnight. Not related to the beer issue, but still frustrating.

The overcarb/freezing beer combined with the change in pressure (from the leak/prv) caused the foaming and the overflow.

It really looked like krausen, but I guess not.

I kegged it last night, should be enjoying it soon. Thanks for the thoughts and help!

 

[brewpharm Hill]

1.6 lbs of lactose (although I think something slightly less actually got dissolved, I think some ended up in the kettle trub).
157 Mash for 60 min, followed by a mash out.
Wyeast 1318 yeast



Target FG was 1.026. Ending up at 1.032 isn't outside the realm of natural possibilities, depending on the health of the yeast, attenuation, and fermentable sugars. So that alone didn't shock me, which gave me enough comfort to cold crash.

I let the carboy sit for 12 hours to naturally "off gas", at 34 degrees (to dissolve whatever ice had formed). I then took a gravity reading, which came in at 1.033, which showed I didn't have a decrease in SG or any apparent signs of fermentation.



I think you're right.

From what I can tell, a few things happened, mainly errors on my end:
1. Every other beer that I cold crashed to below 32 deg had 5%+ ABV. This one is clocking in at ~3.5%, which means I likely had some freezing issues.
2. I most likely overcarbed the beer. I was shooting for 12 psi. On a 30 deg beer, that was too much.
3. It looks like my regulator might not be as accurate as it once was. Even though my regulator was set at 12 psi, it was likely pushing more than that.
4. The PRV on the conical most likely released, and most likely more than once.
5. I had a small leak on the o-ring on the top triclamp. Again, likely do to the high pressure.

The regulator/leak/prv issue resulted in the CO2 tank draining empty overnight. Not related to the beer issue, but still frustrating.

The overcarb/freezing beer combined with the change in pressure (from the leak/prv) caused the foaming and the overflow.

It really looked like krausen, but I guess not.

I kegged it last night, should be enjoying it soon. Thanks for the thoughts and help!

Ahhhh right. 1.6 lbs of lactose is quite a bit, but I would just mash much lower in the future. Probably around 150-154 and see where you end up. London ale III is a great yeast but it's not going to attenuate a wort produced from a mash at 157. I did a raspberry milkshake IPA with london ale III a couple summers ago. Here is the recipe:

I mashed at 154 with London Ale III.

 

[specialkayme]

Good advice, thanks @brewpharm Hill

I was trying to give it a bit more body, so it wouldn't ferment out as much. But 157 was probably pushing the limit. But hey, this is how we learn, right?

 

[brewpharm Hill]

Good advice, thanks @brewpharm Hill

I was trying to give it a bit more body, so it wouldn't ferment out as much. But 157 was probably pushing the limit. But hey, this is how we learn, right?

Damn right. Let’s us know how it turns out!