Ale still fermenting during cold crash

[Brian66]

I have an IPA that fermented for 12 days at 68F. The brix stayed at 9 for a couple days so I started cold crashing. After 1 1/2 days I pulled it out to keg and it was bubbling. I loosened the air lock to take a sample and it was at 8 brix. After putting airlock back it's still bubbling every 30 secs. I guess I'll warm it up again. This ever happen to anyone? Once it's done fermenting, should I cold crash again?

 

[Brian66]

Now that it's warmed up the brix is back to 9 and it's not bubbling anymore. Will keg today.

 

[Dgallo]

Yeah totally normal, as the beer got cold in the crash it started absorbing the air in the headspace of the fermenter(hopefully you had it hooked up to some co2 Source so that it was not oxygen that it absorbed). As it started warming when you took it back out it started degassing. The lower brix is due to temper as well

 

[Immocles]

Sorry to hijack!

Yeah totally normal, as the beer got cold in the crash it started absorbing the air in the headspace of the fermenter(hopefully you had it hooked up to some co2 Source so that it was not oxygen that it absorbed). As it started warming when you took it back out it started degassing. The lower brix is due to temper as well

I'm having something kinda similar that I haven't yet ran into. I made a simple MO/EKG with notty and tossed a small dry hop in about 5 days ago and she's bubbling pretty hard. Not just the airlock, like bubbling along the sides of the beer and foamy on the top as well. I'd planned to bottle on Friday but decided id wait until Monday/tuesday. Temps have been in the 60-65 range throughout. I didn't grab a sample but it was quite still when I hopped. I normally expect a day or two of action, but not going into 5 days. Time to be concerned?

 

[SanPancho]

Unless im mistaken your brew went way wrong. 9 brix is insanely high for a beer to “finish” at outside of RIS or triple barleywine stuuf. Should be more like 2-4 brix for most ipas.

 

[Dgallo]

Unless im mistaken your brew went way wrong. 9 brix is insanely high for a beer to “finish” at outside of RIS or triple barleywine stuuf. Should be more like 2-4 brix for most ipas.

Good catch.

 

[Dgallo]

Sorry to hijack!



I'm having something kinda similar that I haven't yet ran into. I made a simple MO/EKG with notty and tossed a small dry hop in about 5 days ago and she's bubbling pretty hard. Not just the airlock, like bubbling along the sides of the beer and foamy on the top as well. I'd planned to bottle on Friday but decided id wait until Monday/tuesday. Temps have been in the 60-65 range throughout. I didn't grab a sample but it was quite still when I hopped. I normally expect a day or two of action, but not going into 5 days. Time to be concerned?

Did you dryhop during fermentation or after. Without taking a reading it’s hard. Dryhoping can cause hop creep and it will referment some. Natty yeast is highly attenuative, I believe it’s like 85-90% so it’s possible it’s just continuing to eat

 

[Immocles]

Did you dryhop during fermentation or after. Without taking a reading it’s hard. Dryhoping can cause hop creep and it will referment some. Natty yeast is highly attenuative, I believe it’s like 85-90% so it’s possible it’s just continuing to eat

I've had it kick off action before, just not to this length of days. I dry hopped this batch after fermentation since work was getting in the way of brewing. Everything else about fermentation and the time length seemed as expected. My plan was to let it sit the weekend and revisit it on monday. I imagine by then it will be done doing whatever its doing.

 

[Qhrumphf]

Unless im mistaken your brew went way wrong. 9 brix is insanely high for a beer to “finish” at outside of RIS or triple barleywine stuuf. Should be more like 2-4 brix for most ipas.

Unless OP is using a refractometer to tell fermentation is done and not necessarily that the reading is accurate (and would either convert or hydrometer measure later). Presuming that the OP knows what they're doing with that process...

 

[Brian66]

Brix was 9 using a hydrometer reading it was 1.02

 

[Brian66]

Sorry - typo 1.012 was the gravity with the hydrometer

 

[SanPancho]

Those measurements dont correlate. 9 brix/Plato is like in the 30s.

1012 is more like fg for an ale. That’s like 3 brix.

if your hydrometer says 9 brix AND 1012 then get a new one. And make sure you get the bubbles off it when you measure. Skews the readings.

 

[Brian66]

sorry the refractometer says 9 brix and the hydrometer says 1.012. I will adjust the refractometer - which I typically use just to know if fermentation is done. I always use the hydrometer for FG. Thanks for the replies!

 

[Brian66]

So that's weird. I took distilled water to calibrate the refractometer and it was barely off - 1 brix or less off of being zero. What would make the brix read 9 when the FG is 1.012? Even if the temp of the sample was too high/too low I wouldn't think it would be off that much.

 

[VikeMan]

So that's weird. I took distilled water to calibrate the refractometer and it was barely off - 1 brix or less off of being zero. What would make the brix read 9 when the FG is 1.012?

Alcohol makes it do that. You need to use a refractometer calculator to adjust the reading.

 

[jddevinn]

Refractometer won't be accurate after fermentation due to the alcohol present. You can use an approximation to calculate. VinoCalc - by Jonathan Musther

 

[VikeMan]

Refractometer won't be accurate after fermentation due to the alcohol present. You can use an approximation to calculate. VinoCalc - by Jonathan Musther

I wouldn't use a wine refractometer calculator. I'd use something like Sean Terrill's refractometer calculator, which is specifically for beer.
http://seanterrill.com/2012/01/06/refractometer-calculator/
The reason is that there's a Wort Correction Factor to account for the difference between the refractive index of sucrose solution and the refractive index of beer wort.

 

[Qhrumphf]

So that's weird. I took distilled water to calibrate the refractometer and it was barely off - 1 brix or less off of being zero. What would make the brix read 9 when the FG is 1.012? Even if the temp of the sample was too high/too low I wouldn't think it would be off that much.

What you're doing actually works. Use small samples with refractometer to check if fermentation is done, knowing that (because of the presence of ethanol, as indicated above) it won't give you can actual reading, but in you can still verify that readings have become stable. Then use a hydrometer to actually read it.

There are devices out there using a different process to measure that CAN accurately measure with ethanol present using a similar amount as a refractometer (Anton Paar Easy Dens or their DMA35 are two examples, the latter more robust than the former), but they're pricy for most homebrewers (Easy Dens I think is a few hundred bucks, and depending on which DMA model that could be a few thousand).

So barring those, either a hydrometer, or a corrective calculator (Terrill and Novotny are the standard calculations)

 

[Brian66]

What you're doing actually works. Use small samples with refractometer to check if fermentation is done, knowing that (because of the presence of ethanol, as indicated above) it won't give you can actual reading, but in you can still verify that readings have become stable. Then use a hydrometer to actually read it.

There are devices out there using a different process to measure that CAN accurately measure with ethanol present using a similar amount as a refractometer (Anton Paar Easy Dens or their DMA35 are two examples, the latter more robust than the former), but they're pricy for most homebrewers (Easy Dens I think is a few hundred bucks, and depending on which DMA model that could be a few thousand).

So barring those, either a hydrometer, or a corrective calculator (Terrill and Novotny are the standard calculations)

Thanks - I'll use the corrective calculator. I think the confusion came in because I wasn't clear on my initial post that the brix came from the refractometer and the FG came from a hydrometer. Also the bubbling is probably oxygen coming out after the cold crash. Luckily the beer didn't oxidize.

Thanks everyone for the replies!

 

[VikeMan]

Also the bubbling is probably oxygen coming out after the cold crash. Luckily the beer didn't oxidize.

Well... I hate to be the bearer of bad news, but if you cold crashed with a typical airlock setup, oxygen was definitely drawn in, and some of it oxidized the beer. The only question is how much.

 

[jddevinn]

Bubbling is CO2 leaving solution, not oxygen leaving. (You would have to have a LOT of oxygen to reach solubility limit). CO2 solubility increases as the temperature of the beer decreases, so you should get bubbles when the beer warms not when it is cooled.

Cold crashing should be done under slight positive CO2 pressure to avoid oxygenation.

Thanks - I'll use the corrective calculator. I think the confusion came in because I wasn't clear on my initial post that the brix came from the refractometer and the FG came from a hydrometer. Also the bubbling is probably oxygen coming out after the cold crash. Luckily the beer didn't oxidize.

Thanks everyone for the replies!

 

[Ogilthorpe2]

Bubbling is CO2 leaving solution, not oxygen leaving. (You would have to have a LOT of oxygen to reach solubility limit). CO2 solubility increases as the temperature of the beer decreases, so you should get bubbles when the beer warms not when it is cooled.

Cold crashing should be done under slight positive CO2 pressure to avoid oxygenation.

I‘ve never really done cold crashing, so I’ve never worried much about the process, and had never considered the oxidation risk involved. I just started kegging though, and was considering crashing the batch currently in my fermenter, so just curious what your method is for achieving positive CO2 pressure?

What kind of vessel are you using for this etc.

 

[jddevinn]

I‘ve never really done cold crashing, so I’ve never worried much about the process, and had never considered the oxidation risk involved. I just started kegging though, and was considering crashing the batch currently in my fermenter, so just curious what your method is for achieving positive CO2 pressure?

What kind of vessel are you using for this etc.

I have conicals now and just attach CO2 on of the top triclamps, manifold that runs to the fermentors is set to only a coupe psi. When I was using carboys I attached Mylar balloons to the end of the blow off tube after a day or two of fermenting and allowed them to act as a CO2 reservoir for the cold crash and then had another set up for low pressure transfer.

What are you using for fermenting? Ideally whatever system you use for positive pressure cold crash can be used for a closed transfer to the keg after.

 

[Ogilthorpe2]

I have conicals now and just attach CO2 on of the top triclamps, manifold that runs to the fermentors is set to only a coupe psi. When I was using carboys I attached Mylar balloons to the end of the blow off tube after a day or two of fermenting and allowed them to act as a CO2 reservoir for the cold crash and then had another set up for low pressure transfer.

What are you using for fermenting? Ideally whatever system you use for positive pressure cold crash can be used for a closed transfer to the keg after.

I have the Anvil 4 gallon Stainless Buckets. I have the closed transfer down, but like I said I’ve never cold crashed in past, so just never thought about the mechanics of the Vacuum it would create.