Fermentation Temp and Priming Sugar Calc Question

Mashing
1

Getting ready to bottle a CAP, . Fermented at 50F, 3 day diacetyl rest at 60F, then 6 weeks of lagering at 34F. Question: Which of the 3 temps should I use for the residual CO2 calculation when determining priming sugar amount? I’m assuming 60F, as the rise in temp (and fermentation finishing) would off-gas some of the dissolved CO2 I’d find in the beer at 50F.

I’ve always primed my lagers before using the initial fermentation temp, this just popped into my head as I was pulling the carboy out of the freezer this morning. Now, it would make sense to use the diacetyl rest temp for the reason I mentioned above. Any advice / previous experience with this is appreciated. Thanks.

2

Use 60F.

3

Tough question. In 3 days you’d see some of the CO2 gas out, maybe not quite reaching equilibrium though. I’d maybe split the difference and use 55F. Or I’d use 60F and add sugar to get a little on the low side of the CO2 range for the style.

4

Thanks for the replies. Actually primed the beer using 55F as the temp before reading Tom’s response; figured this was a good compromise and wanted to avoid overcarbonation / bottle bombs. Will see how it turns out in 10 days or so.