TriggerHappy
Well-Known Member
If I cold crash a beer to help drop dry hops out will that also drop out most of my yeast? If so how does this affect bottle conditioning/carbonating with sugar in bottles?
Cold crash bottling
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I haven't had any bottle conditioning issues after cold crashing. There are multiple reports from others scattered around HBT that have the same experience.
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d3track
Are you sure about that?
24-72 hour cold crash will leave you enough to bottle
Adjust the carb level to account for increased CO2 solubility when cold crashing and bottle conditioning. Use the brewers friend calculator or the homograph in the appendix of brewing classic styles to carb appropriately taking into account the temp of the beer and therefore the residual co2 in solution at bottling time.
No, you should not adjust the priming sugar amount because of cold crashing. The starting CO2 level in the beer prior to bottling will be determined by the highest temperature the beer experienced while fermenting, and that is the temperature that should be entered into a temperature compensating priming calculator (like the one at BrewersFriend.)
In order for cold crashing to significantly change the CO2 level in the beer, you would need to cold crash for a week or longer, and have to keep replenishing the CO2 in the headspace as it got absorbed into the beer. Neither of these conditions is usually present during homebrew cold crashing. The explanation is a little involved, but if you are interested, then read on.
Let's do an example: In a typical fermenter the headspace is about 20% of the beer volume, so if all of the CO2 in the headspace were to dissolve into the beer, it would add 0.2 volumes to the carb level of the beer. If the fermentation finished at 68°F, then we would have a carb level in the beer of 0.75 volumes (according to the BrewersFriend calculator.) Now we cold crash to 34°F, where the equilibrium carb level at 0 psi is 1.56 volumes. If half of the CO2 in the headspace were to dissolve into the CO2, then the carb level would be 0.75 + 0.1 = 0.85 volumes, and the CO2 pressure in the headspace would drop to -7.35 psig (= 14.7 / 2 = 7.35 psia.) However, the CO2 pressure required to achieve 0.85 vols at 34°F is -7.1 psig = 14.7 - 71 = 7.6 psia, so we cannot even get half of the headspace CO2 to dissolve into the cold crashed beer. And, equilibrium would require about 3 weeks to achieve.
If you were looking for a carb level of 2.5 volumes in your bottles, and entered a beer temp of 34°F into the calculator, it would say that you need to add enough sugar to create 2.5 - 1.56 = 0.94 volumes. However, your actual starting carb level is not 1.56 but somewhere between 0.75 and 0.85, closer to 0.75. Your bottles would end up with something like 0.76 + 0.94 = 1.7 volumes. Thus they would be severely undercarbed.
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bobeer
Fermentation Specalist
I just did this on my last batch. I split it with a friend and I keg. I wanted to drink the beer while we were bottling and I always cold crash. I cold crashed for about 24 hours, kegged half and bottled half a couple days later. I kept his half cold crashing and I was worried too but my buddy said they're carbonated fine.
I typically cold crash the primary at 35*F for a week. It'll make the beer/cider nicely clear and firm up the yeast cake, but there's still enough yeast remaining for bottle carbonation. When not kegging, I prime and bottle the beer while still cold.
With the carbonation calculator, enter the highest temp that the beer saw while in the fermenter. For a normal drinking (not style specific) carbonation, shoot for 2.5 on the CO2 volume.
With the carbonation calculator, enter the highest temp that the beer saw while in the fermenter. For a normal drinking (not style specific) carbonation, shoot for 2.5 on the CO2 volume.
Let's do an example: In a typical fermenter the headspace is about 20% of the beer volume, so if all of the CO2 in the headspace were to dissolve into the beer, it would add 0.2 volumes to the carb level of the beer. If the fermentation finished at 68°F, then we would have a carb level in the beer of 0.75 volumes (according to the BrewersFriend calculator.) Now we cold crash to 34°F, where the equilibrium carb level at 0 psi is 1.56 volumes. If half of the CO2 in the headspace were to dissolve into the CO2, then the carb level would be 0.75 + 0.1 = 0.85 volumes, and the CO2 pressure in the headspace would drop to -7.35 psig (= 14.7 / 2 = 7.35 psia.) However, the CO2 pressure required to achieve 0.85 vols at 34°F is -7.1 psig = 14.7 - 71 = 7.6 psia, so we cannot even get half of the headspace CO2 to dissolve into the cold crashed beer. And, equilibrium would require about 3 weeks to achieve.
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Excellent explanation, but in this case you considered the fermenter a sealed container, but as we use an airlock that do not offer resistance from air movement in any direction we can consider that the pressure in the headspace would be 14.7 psia at all times? Is it right? I'm trying to understand this question....
I did not consider the fermenter a sealed container. Any reduction in CO2 pressure (from temp drop or absorption into the beer) will cause air to suck back thru the airlock. So, the total pressure in the headspace remains at 14.7 absolute psi absolute, but the only thing that matters for carbonation is the CO2 partial pressure (the fraction of the total pressure due to CO2.) At the end of fermentation, no more CO2 is being generated, so the amount of CO2 in the fermenter (beer + headspace) is nearly constant. CO2 that absorbs into the beer will reduce the amount of CO2 in the headspace, and thus also reduce the CO2 partial pressure.
I say CO2 is nearly constant because if the fermenter is subject to thermal cycles (heating and cooling) then during heating headspace gas will be expelled thru the airlock, and during cooling air will be sucked back into the headspace. Headspace gas expelled during heating will contain some CO2, causing the total amount of CO2 in the fermenter to decrease. I did not take this possibility into consideration for my calculations. A small amount of CO2 will also escape by diffusion thru the water in the airlock. This was also not considered.
Does this answer your question?
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I did not consider the fermenter a sealed container. Any reduction in CO2 pressure (from temp drop or absorption into the beer) will cause air to suck back thru the airlock. So, the total pressure in the headspace remains at 14.7 absolute psi absolute, but the only thing that matters for carbonation is the CO2 partial pressure (the fraction of the total pressure due to CO2.) At the end of fermentation, no more CO2 is being generated, so the amount of CO2 in the fermenter (beer + headspace) is nearly constant. CO2 that absorbs into the beer will reduce the amount of CO2 in the headspace, and thus also reduce the CO2 partial pressure.
I say CO2 is nearly constant because if the fermenter is subject to thermal cycles (heating and cooling) then during heating headspace gas will be expelled thru the airlock, and during cooling air will be sucked back into the headspace. Headspace gas expelled during heating will contain some CO2, causing the total amount of CO2 in the fermenter to decrease. I did not take this possibility into consideration for my calculations. A small amount of CO2 will also escape by diffusion thru the water in the airlock. This was also not considered.
Does this answer your question?
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Aswered.....
So if I understood, the point is: The beer can and will absorb some co2 of the fermenter's headspace (considering a cold conditioning without transfering the beer from the primary fermenter), but this re absorption is partial and very small so it shouldn't be considered for residual co2 calculations...
Thanks again
Aswered.....
So if I understood, the point is: The beer can and will absorb some co2 of the fermenter's headspace (considering a cold conditioning without transfering the beer from the primary fermenter), but this re absorption is partial and very small so it shouldn't be considered for residual co2 calculations...
Thanks again
Correct.
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