Bottle Priming Calculations with Open Fermenter

[BrewDorg]

Hi all, just a quick question before I bottle my IPA tonight.

When using online priming sugar calculators, I've always used 2-4ºC in the temperature option, because I cold crash. This is supposed to calculate how much CO2 is already in solution in the beer, so that you don't end up overpriming. This is all fine, but here is my problem...

I don't use a sealed fermenter, just a stock pot with the lid on top. I'm now thinking that maybe CO2 won't dissolve in my beer as the temp drops, like the calculators say, since there is no seal? Would there need to be pressure in order for this to happen? I assume that all these calculators account for sealed containers only.

What temperature would be most suitable to enter in this case? Any insight would be great.

[Drum]

Use the fermentation temp for the priming calculator, cold crashing wont cause much co2 to go into solution unless it's under pressure like in a keg.

[BrewDorg]

Cool that's ok so. I wasn't sure if I was overthinking it or not. The beersmith figure has served me well so far and it lines up with pretty close to the other calculators with fermentation temp plugged in, so I'll go with that.

[Slev]

I thought the fermentation temp should be used and not the cold temp at bottling (ie  if fermented at 18c,  then cooled to 4c, then still use the 18c for calculating priming sugar).  Is this wrong?

[BrewDorg]

Yea after doing a bit more reading, that's does seem to be correct. Highest temperature reached after active CO2 producing fermentation. I was still unsure whether this change is relevant for open fermenters or not. I usually just took the beersmith priming value, but when I used the other calculators I wasn't sure what to put in there.

[Slev]

Would not think that your fermenter with a lid that is not sealed makes a difference in terms of co2,  as whatever co2 by product is given off by the yeast,  will just form a blanket above the liquid, pushing out any o2 in the headspace, and then any excess co2. Airlocks let out any gas,  without any pressure (or very little at most)  build up inside the vessel.  It is not necessary to have an airtight seal. But that seal does keep nasties out,  and is another control to help keep the process repeatable

[BrewDorg]

Yep, this one was a bit of a brainfart. Forgot that even sealed containers would have the airlock attached. IPA is all bottled up now.