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Never Ending Co2 Supply

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fergi

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well this idea is not very well thought out but here it is,instead of buying/renting your co2 bottles etc how would it be if you buy one of those cheap air compressors from the hardware shop,they are going for about 100 dollars,then conect the outlet into a pressure regulator going into your keg,the compressor would charge its main tank then turn off ,the only time it would run would be when the pressure drops,you could have a line in to your fridge set up and the compressor outside.????well it sounds okay from where i am sitting
fergi
 

voota

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I think it is generally accepted that you need pure co2 (or nitrogen) to carbonate your keg. From what I'm reading, you are taking normal air and putting it in the keg. Air contains a few things that you dont want in your keg, namely oxygen, so i dont think it would work. Correct me if i've misunderstood what you are trying to do.
 

pint of lager

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Yes, it would work, BUT, oxygen is the enemy of finished beer.

If you were going to consume all the contents of the keg over a day or so, it would be ok. You could carbonate as you normally do, either by CO2 or by adding dextrose to the keg. Then use regular air to dispense with.

The other issue is the lubricating oil in the pump. Often the air that comes out, smells unpleasant due to rubber seals and oil in the pump.
 

fergi

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well as i said it wasnt really well thought out,but i can see the reasons now for it not working over an extended period,or for that matter any period
cheers
fergi
 

sosman

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fergi said:
well this idea is not very well thought out but here it is,instead of buying/renting your co2 bottles etc how would it be if you buy one of those cheap air compressors from the hardware shop,they are going for about 100 dollars,then conect the outlet into a pressure regulator going into your keg,the compressor would charge its main tank then turn off ,the only time it would run would be when the pressure drops,you could have a line in to your fridge set up and the compressor outside.????well it sounds okay from where i am sitting
fergi
[post="73777"][/post]​
NOOOOOOOOOOOOOOOOOOOoooooooooooooooooo :blink:
 

Trev

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Ahhhhh - now there's an idea!

Why not use the compressor but only when the beer is fermenting.

Connect the outlet of the airlock to a REALLY big ballon so it fills up with CO2. Use a series of valves ( think T piece with 3 valves) to pass this CO2 to the intake of the compressor. Let the compressor charge up your CO2 bottle.

Hang on - don't Megaswill Production Houses (I refrain from calling them Breweries) do something like this? :blink:

Trev

PS - I might get out the old Chemistry 101 books and see if I can work out how much CO2 id actually given off during a ferment :)
 

Trev

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I also once worked out how much that contributes to Global warming, and it turns out to be quite a bit less than a cow standing in a field farting.
Ok, let me see if I understand.

A cow standing in the field makes more CO2 etc than me brewing.

Cows make milk (as well as other baby cows, but lets not allow this logic to degenerate to discussions of the sexual habits of cows).

Logically then, by brewing beer and consuming it, rather than milk, I am helping to lower the overall load of GreenHouse gases on poor old Mother Earth.

I feel all sort of warm and fuzzy on the inside (or is that the Munich Dunkel :p )

Trev
 

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Trev,

Cant find the original post but here it is again.

It worked out that 20 brews a year does only 1% of the damage of a cow farting. But, if you find that homebrew makes you fart, then you start losing again. So yes, feel warm and fuzzy, but whatever you do dont fart.

Saved from something I posted a couple of years ago.

Recently there was some discussion in a home brewing forum on whether it was possible to harvest CO2 from a fermenter, and use it for applications like filling the head space in a conditioning container. This started me wondering if we should be collecting this CO2 and if we didnt, whether it was causing a problem.

You could get a bunch of homebrewers to stick their fermenters close together and pipe the gas from the airlocks or blow-off tubes to a large container. The gas would be at atmospheric pressure, so it would need to be a big container, but would only need to be made out of gas impermeable plastic sheet, so it could be built easily.

But to be of any serious use we have to get the CO2 into a gas cylinder, its a bit impractical dragging our big floppy bag of gas about the place. I see two ways of doing that. One is to freeze our big plastic container down to -79 degrees Celsius. The gas turns to dry ice, and we scrape the crystals off the plastic and shove them in the cylinder, then let it warm up so the dry ice evaporates inside the cylinder. But a temperature that low cant be achieved in my beer fridge. The other option is we use a high pressure compressor to squeeze the gas in our very large container into the little cylinder. A bit of research confirms that such things exist, designed specifically for breweries, to collect the CO2 from fermentation, clean it, compress it and stick it in a tank, which is then used to gas the end product. Looks like a pretty big and complicated unit for a homebrewer though.

So if we cant easily recycle the gas, are we causing a problem releasing it to the atmosphere, and contributing to the buildup of greenhouse gases?

Lets say you do 20 brews a year, at a volume of 22 litres each. Lets also assume that you brew with dextrose (glucose) rather than malt, so that we can assume 100% attenuation. 2 kg of dextrose in your brew will make it about 5% alcohol.

Fermentation of dextrose goes something like
Dextrose C6H12O6 turns into 2 ethanols C2H6O plus 2 carbon dioxides CO2
So we make 2 carbon dioxides for one dextrose molecule consumed.

The molecular weight of dextrose is 180, so 2 kg of dextrose contains 2/0.18= 11.1 moles of molecules. (A mole is just a very big number.) So one brew produces 22.2 moles of CO2 molecules and 20 brews a year makes a total of 444 moles of CO2.
The molecular weight of CO2 is 44, so the total mass of CO2 is 444x0.044 = 20 kg.
(At room temperature, this is equivalent to a volume of 10 cubic metres, so if you collected the gas from your 20 brews you would need a floppy plastic bag 5 m by 2 m by 1 m.)

Now, according to published figures, a dairy cow produces about 100 kg of methane a year from enteric fermentation (burps and farts) alone, more if we take account of decomposition of cow pats. Methane is much more damaging to the atmosphere than carbon dioxide, so when converting methane to carbon dioxide equivalent, the standard is to multiply by about 21. So a cow produces the equivalent of 2,100 kg of CO2 a year from burps and farts alone.

So the short answer, by my simple approach, is 20 brews a year does only 1% of the damage to the atmosphere that a dairy cow can achieve in the same period by standing in a field farting.
 

sosman

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Guest Lurker said:
I also once worked out how much that contributes to Global warming, and it turns out to be quite a bit less than a cow standing in a field farting.
[post="73809"][/post]​
If a cow farts in a field and no one hears it, did it really fart? (assume you didn't smell it either).
 

deadly

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some people have too much time on their hands :wacko: :p
 

barfridge

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deadly: I think you should give your avatar to GL, he's put lots of effort into that line of thought.
 
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