- Joined
- Mar 12, 2007
- Messages
- 6,841
- Reaction score
- 857
Here’s a little debate from over in General Techniques that could use a science-based answer. The question was, "Do I need to bring my beer back to room temperature before I bottle?"
The apparent answer is "no", but the question that comes up next is, does the amount of priming sugar needed change because the beer is cold?
We know that carbonation level is determined by adding the residual CO2 to the amount of carbonation gained from the priming sugar. The carbonation gained from priming is easy to calculate, but the residual amount is what is in question. What’s been suggested in the quotes below is that chilling the beer after it has finished fermenting will add volumes of CO2.
My perspective is that the chart Revvy linked to is referring to amount of CO2 that the beer has the ability to hold at a given temperature and pressure. Not that it will change to that volume of CO2 just because the temperature was changed after fermentation stopped. If the beer warms too much in the carboy after fermentation has stopped it will off-gas CO2 and that CO2 is lost forever. If you chill this beer and don’t add CO2 under pressure, it’s not going to become more carbonated. It has the potential to hold CO2, but only if it is applied under pressure. I interpret the chart to represent the volumes of CO2 placed in the beer by the fermentation process and it’s ability to hold those volumes at the given temperature and pressure combinations.
So, what’s the answer? Is there a legitimate reason to change the amount of priming sugar used if a beer is cold crashed after fermentation is complete? Or do you base you priming sugar calculation on the beers CO2 content before cold crashing?
The apparent answer is "no", but the question that comes up next is, does the amount of priming sugar needed change because the beer is cold?
We know that carbonation level is determined by adding the residual CO2 to the amount of carbonation gained from the priming sugar. The carbonation gained from priming is easy to calculate, but the residual amount is what is in question. What’s been suggested in the quotes below is that chilling the beer after it has finished fermenting will add volumes of CO2.
My perspective is that the chart Revvy linked to is referring to amount of CO2 that the beer has the ability to hold at a given temperature and pressure. Not that it will change to that volume of CO2 just because the temperature was changed after fermentation stopped. If the beer warms too much in the carboy after fermentation has stopped it will off-gas CO2 and that CO2 is lost forever. If you chill this beer and don’t add CO2 under pressure, it’s not going to become more carbonated. It has the potential to hold CO2, but only if it is applied under pressure. I interpret the chart to represent the volumes of CO2 placed in the beer by the fermentation process and it’s ability to hold those volumes at the given temperature and pressure combinations.
So, what’s the answer? Is there a legitimate reason to change the amount of priming sugar used if a beer is cold crashed after fermentation is complete? Or do you base you priming sugar calculation on the beers CO2 content before cold crashing?
...but really, if you want it carbed "right" then let the beer warm back up...
. . . if the beer changes temps (which it does) it lets go or absorbs more co2.
Careful, When you crash cool the beer absorbs a lot of CO2. As it warms up it off-gasses, but don't expect it to be at its normal (for room temp) CO2 level once it reaches room temp