Temp affects sugar amount?

slarkin712 said:

I don't have Beersmith, or know how to use, but I do understand priming. When beer is fermenting obviously CO2 is produced and dissolved into the beer. At a lower temperature more CO2 will dissolve into the beer. So if the beer at bottling time has more CO2 in solution it will require less priming sugar to get the desired amount of CO2. I use the priming sugar calculator at Northern Brewer. It has a field "Current temperature of beer", which affects how much priming sugar is needed. I don't think current temperature of beer is really accurate on judging how much CO2 is in solution. For example, if you ferment an ale at 70F until it is completely fermented out, it will have a certain amount of CO2 in solution which is related to temperature. If you then drop the temp down to 40F to cold crash it does not magically gain more CO2 in solution because of the temperature, it just has more potential to hold CO2 in solution. Atmospheric CO2 will dissolve into solution at lower temps, but that concentration is not as high as what you get from CO2 in solution from fermentation. So when I enter the temp value into the priming sugar calculator I use the temp the beer was at just at the end of fermentation. Some say you enter the highest temp the beer was at during fermentation, but usually these 2 values are pretty close. And bottle conditioning temperature should have no bearing on your final volume of CO2. When you add priming sugar it will add a known volume of CO2 to the bottle regardless of what temperature it is at. All the priming sugar added at bottling will be consumed by the yeast remaining in solution as long as the temperature is high enough so that the yeast are active.

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captgus said:

I have a related question I was hoping someone could answer? If you cold crash your beer prior to bottling, what temp should you allow your corn syrup/water solution to chill to before adding to the beer in your bottling bucket? Or does it even matter if the beer is 50 degrees and the priming sugar solution is 80 degrees?

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slarkin712 said:

I don't have Beersmith, or know how to use, but I do understand priming. When beer is fermenting obviously CO2 is produced and dissolved into the beer. At a lower temperature more CO2 will dissolve into the beer. So if the beer at bottling time has more CO2 in solution it will require less priming sugar to get the desired amount of CO2. I use the priming sugar calculator at Northern Brewer. It has a field "Current temperature of beer", which affects how much priming sugar is needed. I don't think current temperature of beer is really accurate on judging how much CO2 is in solution. For example, if you ferment an ale at 70F until it is completely fermented out, it will have a certain amount of CO2 in solution which is related to temperature. If you then drop the temp down to 40F to cold crash it does not magically gain more CO2 in solution because of the temperature, it just has more potential to hold CO2 in solution. Atmospheric CO2 will dissolve into solution at lower temps, but that concentration is not as high as what you get from CO2 in solution from fermentation. So when I enter the temp value into the priming sugar calculator I use the temp the beer was at just at the end of fermentation. Some say you enter the highest temp the beer was at during fermentation, but usually these 2 values are pretty close. And bottle conditioning temperature should have no bearing on your final volume of CO2. When you add priming sugar it will add a known volume of CO2 to the bottle regardless of what temperature it is at. All the priming sugar added at bottling will be consumed by the yeast remaining in solution as long as the temperature is high enough so that the yeast are active.

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jwalker1140 said:

This is a great explanation. The related issue I'm dealing with is that the amount of CO2 that remains in solution seems to also be a function of how long the beer sits before bottling. Normally I wait three weeks before bottling, and that gives me pretty consistent results. Recently I tried bottling a few batches after two weeks and they were way over carbonated. I guess the extra weeks gives more CO2 to come out of solution. Maybe there are other factors at play but I've since gone back to bottling in ~3 weeks because I like the consistency that seems to give me.

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Yooper said:

That doesn't seem right- once fermentation is done, and no new c02 is created, whether it sits for two hours or two weeks wouldn't change the dissolved c02. It's definitely temperature related, but not time related.

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jwalker1140 said:

But doesn't CO2 come out of solution gradually on it's own, regardless of temperature? I'm thinking about wine as it ages (granted, this happens over a much longer period than the week or so I'm talking about), or even an opened beer that's left out over night. When I taste my beer as fermentation is ending, I taste much more CO2 than I do when I bottle a couple weeks later even though the temperature hasn't changed.

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GetSudz said:

If I'm following this thread right, the temperature to be entered in the calculator should be the temperature at which the beer will be stored after bottling.
The temp at which the sugar is being added should have no bearing on the dissolved CO2.
A warm bottle of beer has more CO2 in the headspace than a cold bottle of beer, hence the reason for less sugar at lower temps.

Physical Chemistry flashback ... PV=nRT
Although I did get a D in this class

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