I do not believe CO2 will settle to the bottom of a vessel and create a blanket of gas under which a liquid can be racked.
The laws of physics and chemistry contradict this. CO2 is heavier than O2, and so CO2 will settle to the bottom of the vessel and create a blanket of gas under which a liquid can be racked. Does this eliminate all O2 pickup? No. Gasses of different density will always mix a bit, especially at their interface. Which leads to another question: does it matter (at the homebrew level)? No, as long as one takes reasonable care to minimize O2 pickup while racking. Also, drink your homebrew fresh! (i.e., quickly, which has never been a problem in my house). I don't mean to start an O2 debate here, but oxygenation at the homebrew level is a colossally overblown non-issue. There seems to be an endless debate about the effect of O2 on homebrew, when really, there are so many other variables that matter far, far more. Here's one (and only one, granted) bit of evidence: http://brulosophy.com/2016/12/19/post-fermentation-oxidation-pt-1-normal-vs-high-oxidation-exbeeriment-results/
If your logic holds we would all be asphixiated from the CO2 pooling on the surface of the earth due to gravity. Convection currents in the atmosphere causes mixing of the gases. Then there is that law of physics and chemistry called Dalton’s law of partial pressures, which says the pressures of the individual gasses act independently, so that in a sealed container they will not be layered. That doesn’t happen instantly, so some pooling happens when you have a source. That is why confined spaces are a safety concern when sources of CO2 are present (breweries are an example). You will be asphyxiated by a concentration of about 10% CO2, so even then some O2 is present.
The take away is that if you just shoot some CO2 into the keg, there will be O2 left in the keg. After some time that CO2 and O2 will equilabrate in concentration, and there will not be a CO2 blanket. The Beer will be exposed to O2. The production standard for Total Packaged Oxygen in bottles or cans is less than 200 ppb, and better packaging lines attain <50 ppb. Yes, that is parts per billion.
I judge a fair amount. About 3/4 of the time in some styles I pick up oxidation in the entries. I’m not talking cardboard, but dull muddled malt flavor, hops that don’t pop (IPAs), sometimes honey aromas, and so on. Cardboard is the final stage of oxidation, and I agree I don’t get that often.
Homebrewers can brew how they wish. If your happy with your beer, that is great. I’m in the camp that wants to make the best beer I am able to.
Topic: AHA Guide to Kegging article (Read 4575 times)
