Walker said:
I have one of those mixers (store bought) from when my wife wantd to make wine (we had to degass the wine), but it's still cheaper and more convenient to shake the **** out of the fermenter.
edit: odd that the use of the mixer in this thread is to get gas into liquid, but the original purpose of the one I bought is to get gas OUT of liquid. I agree that it works, but strange that the same device can be used for exact opposite reasons.
[WARNING]¡Science Impending![/WARNING]
It may seem almost arbitrarily opposite, but it really just adjusts the concentration of gas towards an equilibrium. You're actually driving off gas, AND putting it into solution, and the equilibrium point is when they are both happening at the same rate.
When you degas wine, it's got a high level of carbon dioxide in solution. If it's somehow at a higher concentration than the equilibrium point, then gas will be driven off at a faster rate than it's being dissolved, lowering overall gas (and therefore CO2) content.
I honestly don't know precisely whether wine that's merely stored under atmospheric pressure the whole time (especially if it finished fermenting a while ago — ie, not still generating CO2) can actually exceed that equilibrium point though. But it's not actually that important, because since you're doing it in an open environment, while you're removing CO2 from solution, the "gas" that's being simultaneously dissolved back in is really just air. So what you're removing is about 100% CO2, and what's replacing it has only (roughly) 0.04% CO2.
For example, even if the concentration is only *HALFWAY* to the equilibrium point, then if you manage to agitate it for long enough, the total amount of gas in solution will double, but the amount of actual CO2 will drastically decrease to only about 0.08% (1/1250th) of its original concentration (assuming the air in the immediate environment has the average content of 0.04%).
Now, I oversimplified some things a bit, especially with respect to the actual numbers/math I used, but in the end, there is really nothing "opposite" going on at all, though I do see what you're saying.
