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Old 11-20-2009, 04:17 AM   #1
Aug 2008
Stevens Point, WI
Posts: 453
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...wouldn't the CO2 in the atmosphere float to the ground and we'd all suffocate?
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Old 11-20-2009, 04:22 AM   #2
olllllo's Avatar
Apr 2006
Phoenix, Arizona
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In a completely inert atmosphere and if there were a source crankling out a huge volume of pure CO2 then yes.
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Old 11-20-2009, 04:23 AM   #3
Nov 2009
Pasadena, CA
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Concentration, miscibility (if you can really describe gases as miscible), and convection currents.

Think of the high school chemistry adage "Like, dissolves like". As a crude example consider ethanol and water, ethanol is less than dense than water but you don't get a layer of ethanol floating on top of your vodka, no matter how long you let it sit.

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Old 11-20-2009, 04:26 AM   #4
khiddy's Avatar
Apr 2009
Portland, OR
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The difference is that stuff moves on the surface of the earth... there are temperature differences and weather that keep the air circulating... trees & plants inhale CO2 and exhale oxygen...

If you find any of these conditions in your keg, I suggest you not drink it.
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Old 11-20-2009, 04:28 AM   #5
Yuri_Rage's Avatar
Jul 2006
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Think of it this way: if alcohol is really lighter than water, shouldn't it float to the top of a beer and make the first few sips really strong?

Nope. It's a homogenous solution...much like the atmosphere.

EDIT: Crap. Rushis beat me to the analogy.
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Old 11-20-2009, 03:32 PM   #6
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Oct 2005
Oak Grove, Oregon, USA
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Here's a list of occasions where CO2 flows resulted in fatalities.

There's a recent case where CO2 evolving from a lake-bed killed a bunch of people, but I can't find the reference.

In all cases (like your first brew), insufficient mixing.
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Old 11-20-2009, 03:40 PM   #7
Oct 2009
Posts: 138

The lake bed was methane not co2.. just so you know. Lake Kivu, in Africa.
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Old 11-20-2009, 03:46 PM   #8
Mar 2009
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CO2 is a trace gas being only 0.038% of the atmosphere. CO2 is toxic in higher concentrations: 1% (10,000 ppm) will make some people feel drowsy. Concentrations of 7% to 10% cause dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour.

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Old 11-20-2009, 03:47 PM   #9
Aug 2009
Twin Cities, MN
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CO2 is heavier than "air", (which is nitrogen and oxygen, mostly). In fact, oxygen is heavier than nitrogen.

Brownian motion, random movement of molecules, will mix the gasses eventually. The atmosphere is full of convective currents, (WIND), so it mixes much faster.

If you fill a carboy with CO2 and let it sit open to the atmosphere, however, the CO2 WILL diffuse out into the air, and after a little while the composition of gas inside the carboy will be the same as the composition of gas outside the carboy. We say "blankets of CO2" and "CO2 is heavier than air" because, in sufficiently short timescales, they stay distinct. This is why we have airlocks on carboys, however, because once the rate of CO2 production inside the carboy slows, O2 and N2 will start to mix back in to the headspace.

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Old 11-20-2009, 03:53 PM   #10
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Oct 2008
Philly, PA
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Getting . . . sleepy. Can't keep my eyes open.

I must be in a pocket of co2 concentration. Or could it be from reading Shorty's explanation.
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