The Chemistry of Bottle Priming

[TopherJohn]

I bottled my first batch using a bottling bucket tonight. Every batch before this used sugar funneled into each individual bottle. This is soooo much mor civilized.

I used online calculators to determine the amount of sugar I'd need, and I noticed that when the temperature of the bottles is lower, less sugar is required. Why is this?


"I will make it felony to drink small beer. "

 

[thadass]

duplicate post

 

[thadass]

The fermentation temperature mentioned in priming sugar calculators is actually about the temperature the beer was at before you bottled it.
More specifically, you should enter the highest temperature the beer was at after primary fermentation has completed (the calculators do not explain this at all for some reason).

This is to gauge the volume of CO2 already in the beer. As a beer is fermenting, it is obviously producing CO2, and some of that stays in solution. Colder liquids can hold more CO2 in solution, so a beer fermented at and held no higher than 62F will have much more CO2 left in solution than a beer that was raised to 70F after fermentation.

The reason you use the highest temperature after primary is because as the temperature increases CO2 will leave the beer, but if you chill it back down no more CO2 is going to enter the beer because fermentation is done and the yeast is not producing any more.

So, enter in the right temp and the calculator will use the estimate of residual post-fermentation CO2 to calculate how much sugar you will need to get to your desired carbonation.

 

[TopherJohn]

Brilliant. Thank you.


"I will make it felony to drink small beer. "