bjacokes
Active Member
I've been gently rousing my beer in secondary while dry hopping, which causes a bit of CO2 to bubble out of solution. This got me thinking about the following hypothetical scenario:
Say I have my beer in secondary - assume it's completely done fermenting and has stopped bubbling (maybe it's been sitting there for several months), and it's at a constant 70F. That should mean that the pressure of CO2 in the headspace is one atmosphere. Now I rouse the beer, some CO2 bubbles out of solution and increases the pressure so that some of the CO2 escapes from the airlock. Now if I wait around then some of the CO2 in the headspace will dissolve back into the beer, but in the end, the pressure in the headspace must be less than one atmosphere (because all conditions are the same as before the rousing, but there is less CO2).
Shouldn't this pressure difference mean that the airlock starts pulling air back into the fermenter? And how come I don't see this happen after rousing?
Say I have my beer in secondary - assume it's completely done fermenting and has stopped bubbling (maybe it's been sitting there for several months), and it's at a constant 70F. That should mean that the pressure of CO2 in the headspace is one atmosphere. Now I rouse the beer, some CO2 bubbles out of solution and increases the pressure so that some of the CO2 escapes from the airlock. Now if I wait around then some of the CO2 in the headspace will dissolve back into the beer, but in the end, the pressure in the headspace must be less than one atmosphere (because all conditions are the same as before the rousing, but there is less CO2).
Shouldn't this pressure difference mean that the airlock starts pulling air back into the fermenter? And how come I don't see this happen after rousing?