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Bulk Priming Question

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Truman42

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Probably a stupid question, but hey may as well ask it. Ive been reading up about bulk priming and using a bulk priming calculator. It says..

Upon completion of fermentation, a certain amount of CO2 remains in the beer. This amount of "residual CO2" depends upon the temperature of the fermentation. An ale fermented at 65F will have 0.9 volumes of residual CO2 while a lager fermented at 50F will have 1.2 volumes. To get the same carbonation in these two beers would require different amounts of priming sugar.
But does this temperature relate to the fermenting temp only? What if I CC at 1C for 5 days then pull it out of the fridge and rack to my bottling bucket, the temp might only be around 10-15C, so is this what figure I put into my bulk priming calculator or will I still put in 20C as that was my fermenting temperature?
 

manticle

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Highest temp reached during OR after ferment temp, excluding very sharp spikes.
 

pk.sax

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T

% of CO2 in atmosphere is bugger all, so when you chill it back down it reabsorbs gas, very little but still, but that is standard air being absorbed, prime and cap, the yeast use up the oxygen so that extra pressure is lost.
Anyway, that is like dividing 0.00001 by 10000. (please don't kill me for the generalised approximate explanation)

In essence, the CO2 driven out by a higher temp in an unpressurised container (fermenter) will not go back in. The equalisation is with air, which gets used up by yeast so should not be considered when calculating pressure. The warmest it got to while fermentation was active (towards the end) and after is the right temperature. easy way to deal with it is to give it a diacetyl rest (raise temp a few degrees at end) and use that as the temp for calculation.
 

Truman42

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Thanks for the advice.

PF, I wanted to raise temps for a diacetyl rest and reset the temp control on the fridge to 22C but bloody Melbourne weather went cold on me when I did and instead it dropped to 17C. That's why Im now in the process of setting up heating for my fermenting chamber. (Hadn't needed one until now)
 

pk.sax

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haha.. u've got a fridge though :p
I remember moving my first few brews around, positioning them closer to the ducted heating outlets!!!!

Just bring a kettle full of water to the boil, pour into a rubber bottle or something and put it in the fridge. Unplug fridge, leave STC plugged in to monitor temp.
 

Truman42

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haha.. u've got a fridge though :p
I remember moving my first few brews around, positioning them closer to the ducted heating outlets!!!!

Just bring a kettle full of water to the boil, pour into a rubber bottle or something and put it in the fridge. Unplug fridge, leave STC plugged in to monitor temp.
Actually that's what I meant. I reset the temp on the Stc to 22. And normally with the summer ambients it Would climb to this in my garage and in my ferm fridge. I Would leave the fridge plugged in just in case it climbed over 22.
Never thought of using water bottles with hot water. Oh well next brew I should have some heating sorted.
 

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