Calculating sugar addition for natural carbonation

[thatguy314]

I was wondering if any of you could help give me a refresher. I fermented a bitter at 68 degrees, then chilled it to 50 degrees to drop the yeast.

I'm going to ferment it in a corny and put it on a hand pump as a faux-cask, so I need to naturally condition it.

When I'm calculating the sugar addition for carbonation, do I use the current temperature (of 50F) or do I use the fermentation temperature (68)? Thanks.

[Quin]

I think you would need to use 68°. If fermentation was complete, no additional CO2 has been generated to get you to saturation at 50°.

[Sathington Willoby]

I think you would need to use 68°. If fermentation was complete, no additional CO2 has been generated to get you to saturation at 50°.

Yeah, but wouldn't the beer absorb the CO2 from the air around it as it chilled? At least to a certain degree.

To a very small degree. It would take a looong time to get to saturation without yeast generating CO2 and/or the vessel being under pressure.