carbonation calculator: fermentation temp, cold crash temp, bottling temp?

Which temp do I use in a carbonation calculator?
1) the temp it fermented at
2) the temp it coldcrashed/lagered at
3) the temp it's at when the sugar is added?

Related question: Do I need to heat it up after cold crashing before bottling?

Thanks!

 

Whatever temp it is at when you are carbonating it.

Like my kegs are in my fridge carbonating so the the fridge is 38F so the temp you use in the calculations is 38F.

 

Wrong.

It's the highest temperature your fermenter was stored at for any significant length of time after fermentation was complete. It’s all about how much CO2 is already in suspension when you bottle. The warmer your beer is stored after fermentation, the more CO2 will leave through your airlock. Even if you chill it after this (cold crash) the CO2 in suspension will not increase. The small amount remaining in the headspace is not enough to make a difference. Once it’s gone, it’s gone.

No, but you do need to bring the bottles up to room temperature after bottling.

 

I am talking about CO2 carbing kegs you must be talking about bottling. I see now his question pertains to bottling. Keg carbing with CO2 is about the temp of the beer and psi, while it's carbing.

 

Actually the OP did say carbonation calculator which would imply kegging. "Priming Calculator" would have been a better choice of words.

 

This kept bugging me too, BeerSmith says to use the temperature at bottling.

 

Thanks everyone. I did indeed mean priming.

 

Bringing this up again. It was said that you should use the warmest temperature it was stored at for any "significant amount of time".

Any rule of thumb for what that means? If I transfer from primary to secondary, I'm assuming it warms up quite a bit during that time, but it's probably only like 30 min or so?

More extreme - doing a D-rest for 2 days before lagering? Is that significant amount of time?

Finally, I wonder what temp the beer ends up at in the bottle after a bottling session... if I pull it out of a 35 degree cold crash, let it sit a bit in the room, transfer to bottling bucket, transfer to bottle... maybe it ends up at 50? maybe at room temp? Guess I should measure next time as an experiment.

Thanks.