So, I’m bottling my lager this weekend, which has been sitting in my brew freezer at 36 degrees.
Question: Do I prime and bottle at the lagering temp, or do I bring it up to room temp before priming and bottling?
Prime it at whatever temp you want… But use the highest post-fermentation temperature at which the beer sat for your priming sugar calculator. So if you did a d-rest, use this temperature. Condition at room temp.
The lagers I did last winter, I brought them right out of the lagering chamber and bottled them cold. Is this what you’re asking?
[quote=“porkchop”]Prime it at whatever temp you want… But use the highest post-fermentation temperature at which the beer sat for your priming sugar calculator. So if you did a d-rest, use this temperature. Condition at room temp.
The lagers I did last winter, I brought them right out of the lagering chamber and bottled them cold. Is this what you’re asking?[/quote]
Yes, that’s what I’m asking. Thanks, Porkchop.
I’ve always wondered why the temperature plays into this. Can anyone explain?
The amount of gas that can be dissolved in a liquid is a function of the liquid’s temperature. Cold liquid holds CO2 much better than warm liquid, which is why people force carbonate at cold temperatures, as the CO2 dissolves better into the cold liquid.
Once active fermentation is complete, no more CO2 is being produced by yeast in the beer. This represents the total amount of CO2 dissolved prior to carbonation. The liquid will off-gas CO2 until it comes into equilibrium, which is why your airlock may bubble for a few days if a weather front comes through, because dissolved CO2 is coming out of solution from lower atmospheric pressure, not because the yeast become active again.
To use the priming sugar calculators, you need to know how many volumes CO2 are already dissolved in the beer, and the calculator gives you the appropriate sugar to achieve the desired carb level. Since warmer beer holds less CO2, it will equalize to the amount dissolved at the highest temperature. You can drop temp after that, but since no more CO2 is being produced, you only have what the solution could hold at its highest temperature.
Just making up some numbers, but say you had 0.5 volumes dissolved in your beer because you held it at 70F or so. If you wanted to get to 2.5 volumes of carbonation, you would add enough sugar to add 2 more volumes to get to 2.5 total. Again, (just making up numbers!) if you fermented a lager, never went over 50F and did NOT do a d-rest, maybe you have 0.75 volumes dissolved due to temperature. To get to the same 2.5 volumes carbonation, you would add enough sugar to add 1.75 volumes of CO2.
