What temperature should I use to calculate how much priming sugar I need to bottle condition when I’ve fermented warm (80F) and then cold crashed to 34F.
My intuition tells me that I should use the warmer temp, since I don’t think the cold crash would force CO2 out of suspension. Thoughts?
Cheers, Jeff
Your warmest point. Here is a calculator that might help: Priming Sugar Calculator — Mr Malty . It is completely free. No tracking. No ads.
What if you do a cold crash with a CO2 reservoir, such as a mylar balloon, and package at that cold temperature? I know that the beer is absorbing CO2 from the headspace because I see the balloon continue to shrink for a couple of days after the low temperature is achieved. If there were no balloon it would be different, but in my case I think the lowest temperature is the one to use because the beer has absorbed as much CO2 as it can at that temperature, which is more than it would hold at fermentation temperature.
Yes, attaching some sort of bag to collect CO2 at warmer temps and then chilling down with the bag attached would help some, but there are a couple things to consider. The first is that you will never be at super saturation, like you are during and for some time after fermentation stops. Of course, if you are in the habit of leaving your beer for several days after the yeast stop producing CO2, the super saturation drops anyway. If your bag of CO2 is fairly pure, then yes you do increase CO2 as the beer chills. How much depends on how big the bag, how pure it was, etc. While that might save you a little in priming sugar or bottled CO2, I don’t feel like it is worth it. You are trapping some compounds that were blowing off during fermentation and then reintroducing them to the beer, which is less than desirable. So, yes, that is a great understanding of how the partial pressure of gases works, but probably not worth the hassle.
Thanks for the insight. I don’t do it to reduce the amount of priming sugar. I do it as an anti-suckback measure during cooldown. I have a hose all set up with a tee, from which one arm fills the balloon and the other arm goes to purge a keg and then through a blowoff jar. I put this together years ago and just need to attach one end to the fermenter and one end to the keg, so it is not a hassle at all. I hadn’t thought about reabsorbing compounds that are blown off - that is the first downside I have heard about.
Thanks Jamil. That’s what I suspected but I couldn’t find it confirmed anywhere.
Cheers