I have a question that has been perplexing me. At least it is making me doubt what I thought I knew.
Does the beer, if set at a constant pressure and kept at a constant temp, eventually reach equilibrium, where it will take on no additional volumes of CO2?
I thought so, but I was listening to an old Brewing network podcast last week. Jamil was talking about taking the beer off the gas when it reaches the perfect carbonation level so that you don't over carbonate.
I have always operated under the assumption that if I set my regulator at X psi at Y temperature in order to get Z level of carbonation, once I hit that level, I am done and can serve at that pressure throughout the life of the keg. I have pretty long beer lines (10 feet) and have balanced my system to get a good pour at 12 psi. At the temp at which I serve, 12 psi is usually in the neighborhood of 2-2.25 volumes (the amount of carbonation I prefer in most of the styles I brew).
If I set the gas at 12 psi at 45F, my beer should carbonate to approximately 2.26 volumes. But my question is, if I leave the beer hooked up to that pressure at that temperature, will I eventually go above 2.26 volumes? Or will I reach equilibrium and stay at a relatively static pressure level?
Everything I learned in science classes leads me to believe that balance is balance. That when the amount of pressure the headspace is exerting on the liquid equals the amount of gas pressure coming from the liquid, my beer will stay at a constant level of carbonation.
But Jamil's comments make it sound like the beer will take on additional carbonation the longer it stays at a consistent pressure.
Am I missing something in my logic? Or did I simply misunderstand what he was talking about. It's possible that he meant that it would pass "optimum" carbonation if you were applying pressure to the keg that would eventually have you at 2.5 volumes, but the beer tasted right to you at 2.25. At that point, you would not reach equilibrium until the beer hit 2.5.
Does the beer, if set at a constant pressure and kept at a constant temp, eventually reach equilibrium, where it will take on no additional volumes of CO2?
I thought so, but I was listening to an old Brewing network podcast last week. Jamil was talking about taking the beer off the gas when it reaches the perfect carbonation level so that you don't over carbonate.
I have always operated under the assumption that if I set my regulator at X psi at Y temperature in order to get Z level of carbonation, once I hit that level, I am done and can serve at that pressure throughout the life of the keg. I have pretty long beer lines (10 feet) and have balanced my system to get a good pour at 12 psi. At the temp at which I serve, 12 psi is usually in the neighborhood of 2-2.25 volumes (the amount of carbonation I prefer in most of the styles I brew).
If I set the gas at 12 psi at 45F, my beer should carbonate to approximately 2.26 volumes. But my question is, if I leave the beer hooked up to that pressure at that temperature, will I eventually go above 2.26 volumes? Or will I reach equilibrium and stay at a relatively static pressure level?
Everything I learned in science classes leads me to believe that balance is balance. That when the amount of pressure the headspace is exerting on the liquid equals the amount of gas pressure coming from the liquid, my beer will stay at a constant level of carbonation.
But Jamil's comments make it sound like the beer will take on additional carbonation the longer it stays at a consistent pressure.
Am I missing something in my logic? Or did I simply misunderstand what he was talking about. It's possible that he meant that it would pass "optimum" carbonation if you were applying pressure to the keg that would eventually have you at 2.5 volumes, but the beer tasted right to you at 2.25. At that point, you would not reach equilibrium until the beer hit 2.5.
