What temperature to use?

Asking for some thoughts and help as to priming sugar at bottling. I usually do ales and use the calculator at Northern Brewer (Homebrew Priming Sugar Calculator). Ales are pretty straight-forward and I use the maximum temperature during fermentation at the current temperature. My most recent batch is an Alt that fermented at 66*, then dropped the temperature to 32-33* and held it there for the past month.

It haven’t ever had a beer where I kept it at cold temperatures for an extended period of time and am asking whether I should use 66* or 33* as the temperature for calculating the priming sugar addition?

If I use 66*, I would add 2.67 ounces of dextrose to get 2.3 volumes of CO2. Using 33* it comes out to 1.40 ounces. Quite a bit of difference.

I know that increased temperature will expel CO2 from the beer and, to some extent, decreasing temperature will retain CO2 and have some re-enter the beer. But how much CO2 will re-enter the beer when going from 66* to 33*? Since the beer has been at 33* for 1 month, I am thinking of using the 1.40 ounces.

Any help or guidance would be appreciated.

I was recently told to use the peak fermentation temperature.

Peak Temperature. The CO2 driven off during fermentation at higher temperature doesn’t go back into solution.

Yes, peak temp.

Thanks guys. I appreciate the help.

I think it’s peak temperature after fermentation has stopped.