Beer Forum

I have a question with regards carbonation. The last brew I did I started the fermentation at 17C let it rise to 19C on it's own then kept it there for 3 days, once the bubbler slowed significantly I raised the temp about 1C/day to 21 where I left it for another 7 days. The day before I wanted to bottle I cold crashed the beer to 3C to try to get it to clear, this seemed to work well as the beer is well attenuated, tastes very clean and the beer came out very clear.

Now the question the fermentation essentially happened at 21C, at this temp you would have a certain solubility of CO2, now when I bottle after cooling the beer do I use 21C or 3C in the calcs for carbonation, the beer I just did I used 21C as I figured that there wouldn't have been any more CO2 being dissolved into the beer when I cooled it.

Is this correct?

Cheers
Grant

The way I understand it is that you use the temperature of the beer at the moment you are bottling. You will also want to let the beer warm to room temps or so (68 degrees) before bottling to help the yeast condition in the bottle.

I've always wondered this too but since I mostly keg now I haven't bothered to really figure it out.

I would tend to agree with your hypothesis that once the CO2 has equilibrated at the warmer temperatures, no further CO2 will dissolve into the beer when it's chilled. So I would use the value for CO2 at 21ºC rather than 3ºC.