Less kegs dispensed with 30/70 beer gas as compared to straight CO2?

[kal]

Hi everyone,

Assuming all things are equal and kegs that are pre-carbed, will someone be able to dispense more kegs with a tank of 100% CO2 as compared to using a tank of 30/70 beer gas (CO2/Nitro mix)?

I could have sworn people here mentioning that their 30/70 beer gas tanks are not dispensing as many kegs as just straight CO2, but I can't seem to find any of the links.

Reason for asking:

I have 6 regular taps served with CO2 from this smaller 10 lb tank, and 2 stout taps served with 30/70 beer gas from a larger 20lb tank.

We drink a lot more from from 6 CO2 taps so I'm considering swapping the tanks so that I have less refilling to do.

Thanks!

Kal

 

[day_trippr]

If the beer is already fully carbed for its dispensing temperature, it won't be absorbing any more CO2, so (it seems to me) that a beer gas mix should displace just as much beer as straight CO2.

otoh, if you were going to carb with the gas, there would be a huge difference...

Cheers!

 

[DrunkleJon]

Beer gas is at a higher pressure than straight CO2 tanks so I really do not think that they would fill your CO2 with it. As a result you may get more mileage out of beer gas than CO2, not even counting the fact that if you have the regulator too high the CO2 will dissolve into solution where the nitrogen will not.

 

[kal]

Beer gas is at a higher pressure than straight CO2 tanks so I really do not think that they would fill your CO2 with it.

Not sure what you mean by "fill your CO2 with it". Do you mean "fill your CO2 tank with it"?

The 10# and 20# aluminum tanks I have are not specific to beer gas blend or CO2. You can use the tank for either. The valves and regulators however are specific to what gas you use.

The valve looks like this:

Regulator looks like this:

The valve attaches to the tank and the regulator attaches to the valve.

Right now I have a 10# tank with a CO2 valve and a CO2 regulator, and a 20# tank with a Nitro valve and a Nitro regulator.

If I was to swap tanks, I would remove the valves and the regulators from both and swap them (after emptying the tanks completely of course).

In fact, when I bought the 20# tank it came with a CO2 valve already attached (the place I purchased doesn't sell just the tank) so I ordered a Nitro valve separately and had the filling place take the CO2 valve off and put on the Nitro valve. This is allowed as the tank itself can hold the higher pressure required by Nitro.

What I don't know is if you get "less" beer gas (Nitro/CO2 blend) in the same amount of tank space as I don't know if it compresses easier or better than just straight CO2. I could have sworn that people here mentioned to buy as large a tank as possible for beer gas as you go through it faster than regular CO2. That's the part I'm trying to confirm.

Kal

 

[old-pasture-brew]

Hey kal,


Forgive me for not having the technical details on why but from what I am told you get noticeably less from a tank of beer gas vs co2, all else equal. It has to do with density of the nitrogen. My supply guy has talked me out of using beer gas several times (as he knows well that I am trying manage cost) for this very reason. Which is killing me because I really like the stouts and there's no denying the nitro goodness. Faucet is pretty cool too. Hmm. Maybe if I cut the kids swim lessons I could sav.......

 

[kal]

Have them swim in beer.

I've heard the same thing but can't fine any real good evidence to it or any numbers. I'm trying to figure out what the drop in usage may be.

For example, completely making up numbers here but if I can get (say) dispense 70 kegs from a 20# tank of CO2, how much does that drop with a 30/70 beer gas blend? Down to 50? 20? 5?

I'm trying to get a rough estimate guage.

Maybe the easiest thing to do is just keep track of it myself and count the kegs and see.

Kal

 

[DrunkleJon]

Not sure what you mean by "fill your CO2 with it". Do you mean "fill your CO2 tank with it"?l

Correct. I lost a word there. Looks like I was mistaken. Found a good article on the differences between beer gas and CO2 here.

They also say...

CO2 will last much longer than beer gas so one may as well use the largest practical standard CO2 tank.

so it looks like you get more mileage out of CO2 afterall.

 

[kal]

Thanks for the link. Good reading there.

My quest for quantifying the statement "CO2 will last much longer than beer gas" continues however!

I'd love to get some actual numbers or at least orders of magnitude.

Kal

 

[DrunkleJon]

I think it is due to density. though with CO2 being a C at a periodic table weight of 11, and two O's at 16 each, where a N is approximately 14. That doesn't make sense then.

I also have been unable to locate anything even semi authoritative to say one way or the other.

 

[old-pasture-brew]

According to engineeringtoolbox.com co2 has a density of 0.1150 lbs/cubic ft vs nitrogen at 0.0727lbs/cubic ft. So nitrogen gives you 63% of the density as comp to co2. Assuming your beer gas is mix of 70/30, that works out to 74.1% (30%+[70%*63%)

My guess, you would end up getting 7.4 kegs on beer gas for every 10 you would have gotten from co2.

 

[zachattack]

Let's say you need 14 psi of CO2 in the keg to maintain carbonation. That means you'd need 47 psi of 30/70 CO2/N2 to maintain that carb level. Since the empty keg is going to be pressurized to 47 psi once it kicks, that's a whole lot of wasted beer gas.

I think beergas is actually in the tank as a gas, not a liquid like pure CO2. So the densities inside the tank will be very different and you'll have a hard time comparing the two just by the rated weight of the cylinder. Something like standard cubic feet would be a better number to compare.

 

[kal]

Thanks! Does the 1800 PSI (CO2) vs 3000 PSI (N2) tank pressure fit into this anywhere? I'm guessing not since when filling with either CO2 or a blend, it's done by weight (I think).

7:10 ratio isn't bad. It would make sense for me then to use the 20# tank for C02 as we probably drink CO2 beer to beer gas beer at a 5:1 ratio if not higher.

Kal