Priming/Carb - what temperature?

[buggslife]

A pretty geeky question here, but what better place to ask it?

When priming for carbonation we compensate sugar addition depending on beer temperature at time of bottling.

Question is, what temperature to take?

The reason we care is because cold liquid is able to hold onto more gas (CO2) in solution than hot.
Therefore, you need less additional carbonation through priming for cold beer than warm beer.

As beer warms up, more gas is released and we see/hear it exit the airlock.

What if you have a multi-stage fermentation?
E.g. Primary: 3 days at 20C, secondary: 10 days at 12C, cold crash: 3 days at 1C.

Should we assume most CO2 is lost during primary and use temperature of 20C for priming calculation?
Do we take 1C since that is the state at bottling?

I'm genuinely not sure.

If anyone can point me towards decent literature on the subject it would be much appreciated.

Note: I'm talking bottle conditioning here, of course not force carbonation etc.

[Aaron]

I just plug the bottling temp (about 3C) into an online priming calculator (brewersfriend). The beer still has a fair bit of CO2 in after primary and cold conditioning.

[jaroporter]

it's been reasonably heavily debated on forums and it seems impossible to give a definitive answer. short of completely degassing the beer (like you would for wine) and starting from scratch I can't see how anything other than trial and improvement would work. if your fermentation routine is pretty consistant then you'll soon learn what works for each level of carbonation. I think the brewers friend makes some mention of what temperature to use..

..

* Temperature of Beer used for computing dissolved CO2:
The beer you are about to package already contains some CO2 since it is a naturally occurring byproduct of fermentation. The amount is temperature dependent. The temperature to enter is usually the fermentation temperature of the beer, but might also be the current temperature of the beer. If the fermentation temperature and the current beer temperature are the same life is simple.

However, if the beer was cold crashed, or put through a diacetyl rest, or the temperature changed for some other reason... you will need to use your judgment to decide which temperature is most representative. During cold crashing, some of the CO2 in the head space will go back into the beer. If you cold crashed for a very long time this may represent a significant increase in dissolved CO2. There is a lot of online debate about this and the internet is thin on concrete answers backed by research. We are open to improving the calculator so please let us know of any sources that clarify this point.

[Fil]

My 2ps worth is use the warmest post primary temp. Without an active fermentation there is no source of co2 to replenish that which was lost when the liquor reached its natural equilibrium after fermentation activity was rampant at its highest rest temp.

granted crash chilling will increse the capacity for absorbed co2 but without the positive pressure found in a keg/bottle/pb to force that co2 into suspension or the result of fermentation providing a tide of rising micro bubbles of co2 for absoption where is the co2 going to come from??

if just chilling added co2 we could simply enliven flat pop, beer, and sparkling wine by sitting it in the fridge overnight.

hope that makes sense

[simon12]

Chilling after primary will cause more of the CO2 still sitting on top of it to dissolve into it regardless but if its sitting for some time at say 20C the amount there to be dissolved and the amount already dissolved will deplete slowly.

[Matt in Birdham]

My 2ps worth is use the warmest post primary temp. Without an active fermentation there is no source of co2 to replenish that which was lost when the liquor reached its natural equilibrium after fermentation activity was rampant at its highest rest temp.

granted crash chilling will increse the capacity for absorbed co2 but without the positive pressure found in a keg/bottle/pb to force that co2 into suspension or the result of fermentation providing a tide of rising micro bubbles of co2 for absoption where is the co2 going to come from??

if just chilling added co2 we could simply enliven flat pop, beer, and sparkling wine by sitting it in the fridge overnight.

hope that makes sense

I do the same. In theory, if you have fermented under an airlock then all of the headspace will be CO2 and could dissolve back into the beer when you crash chill it. In practice, I often leave beers crash chilled for a week or more and always use 20c as the temp when calculating sugar additions in BS (back in the bottling days, anyway ) and never found my beers to be over carbonated.