How Long can I Cold Crash 🍺

[Bayou Fatma Brewer]

Cold Crashing in my Stainless Fermenter.
How long can I keep cold crashing my 5 gallons of Homebrew? Do to circumstances beyond my control, I may have to let it go for over a week. It’s at 39 degrees. Was wondering if there’s any side effects on the Brew if crashing it to long ?
thanx…
Cheers !

 

[BrewerofBeers]

That sounds perfect. You can cold crash for months or even indefinitely, hypothetically. No damage done. Note that more yeast have dropped from suspension if you plan to prime with sugar. Other side effect is oxidation if it got inside the fermenter before/during old crash.

 

[Sammy86]

The only side effect of extending cold crashing in my experience is better tasting beer. The brew will be fine!

 

[Bayou Fatma Brewer]

That sounds perfect. You can cold crash for months or even indefinitely, hypothetically. No damage done. Note that more yeast have dropped from suspension if you plan to prime with sugar. Other side effect is oxidation if it got inside the fermenter before/during old crash.

Thanx…that’s a relief

 

[day_trippr]

What style of beer is this?

If you can prevent O2 from being sucked into your fermentors you could leave them "crashing" for as long as necessary with little risk of degradation. If not, every day that passes will allow the sucked in O2 to oxidize the beer. And beers that are highly hopped like New England IPAs are like oxidation canaries that will not tolerate O2 exposure at all...

Cheers!

 

[FloppyKnockers]

You will reach a point where it's no longer cold crashing - it's lagering.

 

[mac_1103]

The amount of CO2 dissolved in the beer will increase if you crash for a very long time. You will need to account for this if you bottle condition (unless you bring the beer back up to ambient temperature for long enough to release the CO2 it absorbed from the headspace). I guess it won't matter if you "set and forget" force carbonate, since it's going to reach the same equilibrium point anyway.

 

[FloppyKnockers]

The amount of CO2 dissolved in the beer will increase if you crash for a very long time. You will need to account for this if you bottle condition (unless you bring the beer back up to ambient temperature for long enough to release the CO2 it absorbed from the headspace). I guess it won't matter if you "set and forget" force carbonate, since it's going to reach the same equilibrium point anyway.

I'm sure that the increase would be negligible. I've crashed, lagered, and forgotten about many beers in fermenters and never noticed a carbonation difference. Smaller batches - maybe, but five gallons or more at a time I would think not to worry.

 

[mac_1103]

I'm sure that the increase would be negligible.

I recently learned from experience (with a big assist from @doug293cz) that 48F for a month takes five gallons of beer from 0.86 to (1.15-)1.25 volumes of CO2. Whether this is negligible is left to the reader as an exercise.

 

[doug293cz]

I recently learned from experience (with a big assist from @doug293cz) that 48F for a month takes five gallons of beer from 0.86 to (1.15-)1.25 volumes of CO2. Whether this is negligible is left to the reader as an exercise.

Yes. This assumes that the headspace is 100% CO2 at 0 - 1 psi gauge pressure. Higher pressures will give higher carb levels.

Brew on

 

[FloppyKnockers]

Yes. This assumes that the headspace is 100% CO2 at 0 - 1 psi gauge pressure. Higher pressures will give higher carb levels.

Brew on

The volume of the headspace would be a big factor in this too, yeah? Two gallons in a six gallon bucket vs only a couple inches of headspace in the same six gallon bucket.

I'm in the latter which could contribute to the lack of noticing any carbonation issues.

 

[doug293cz]

The volume of the headspace would be a big factor in this too, yeah? Two gallons in a six gallon bucket vs only a couple inches of headspace in the same six gallon bucket.

Nope. It's all about the concentration (pressure) of CO2 in the headspace vs. concentration of CO2 (carb level) in the beer, and temperature.

Brew on

 

[mac_1103]

The volume of the headspace would be a big factor in this too, yeah? Two gallons in a six gallon bucket vs only a couple inches of headspace in the same six gallon bucket.

In my case, I had very little headspace in a five gallon carboy, but a CO2-filled 2.5 gallon cold-crash guardian attached.

 

[FloppyKnockers]

Nope. It's all about the concentration (pressure) of CO2 in the headspace vs. concentration of CO2 (carb level) in the beer, and temperature.

Brew on

Yes, but assuming no pressure (or ~15 psi)? Unless I missed something about OP fermenting under pressure.

 

[FloppyKnockers]

...but a CO2-filled 2.5 gallon cold-crash guardian attached.

Ahhh... could this be the variable? I just use a blow-off tube going into some sanitizer.

 

[mac_1103]

assuming no pressure (or ~15 psi

Yes. 0-1 psi gauge pressure is one atm plus 0-1 psi.

 

[mac_1103]

Ahhh... could this be the variable? I just use a blow-off tube.

And what about suck-back?

 

[FloppyKnockers]

And what about suck-back?

I was afraid of that at first, but the tube is 1/2" diameter and extends below the bottom of the bucket. I've noticed some sanitizer come up the tube, but none that actually made it back into the fermenter.

 

[mac_1103]

I was afraid of that at first, but the tube is 1/2" diameter and extends below the bottom of the bucket. I've noticed some sanitizer come up the tube, but none that actually made it back into the fermenter.

After how long? If your bucket isn't pulling some vacuum when you cold crash, then your bucket is most likely not air tight. Which would mean that you're not getting an increase in carbonation because the headspace is (probably a lot) less than 100% CO2.

 

[FloppyKnockers]

After how long? If your bucket isn't pulling some vacuum when you cold crash, then your bucket is most likely not air tight. Which would mean that you're not getting an increase in carbonation because the headspace is (probably a lot) less than 100% CO2.

This crossed my mind too. Generally I don't cold crash, I'll lager. Dropping the temp a couple degrees everyday until I reach lagering temps. When I do cold crash, I will drop the temp from ale (~65°) to about 34° for a couple days. Maybe gelatin, maybe not.

When I had a plastic blow off tube, the seam on the tube gave less than stellar sealing. You could actually feel air when you pushed on the lid. Switching to a SS one helped a lot. It's still possible a grommet or lid seal isn't what it could be.

Must've been this way since the beginning of beer time for me as this whole extra carbonation thing before carbonating is all new to me.

Edit: Or...sometimes it'll just have the S airlock so it'll just bubble backwards introducing air and thus, like you said, making the headspace a lot less than 100% CO2.

 

[doug293cz]

Or...sometimes it'll just have the S airlock so it'll just bubble backwards introducing air and thus, like you said, making the headspace a lot less than 100% CO2.

Even in this case, the beer will still pick up CO2 from the headspace when you cool it. How fast you cool it doesn't affect the end result. In the case of air suck back, the CO2 partial pressure is not constant, so in this case headspace volume to beer volume ratio will affect the amount of additional carbonation from cooling. I did a full analysis here.

Brew on

 

[passedpawn]

Cold Crashing in my Stainless Fermenter.
How long can I keep cold crashing my 5 gallons of Homebrew? Do to circumstances beyond my control, I may have to let it go for over a week. It’s at 39 degrees. Was wondering if there’s any side effects on the Brew if crashing it to long ?
thanx…
Cheers !

I've got 4 fermentors that have been cold 33F crashing for 10 days, mostly due to me busy with home projects. It's great! I'll get them kegged this weekend.