46 replies to this topic

[gnef]

I can attest to how long an 80 cf tank of beer gas can last. I've had mine for around 4 years now, and am still on the original fill. My pressure is down to 1200 psi. Granted, I haven't run too many beers through it, but enough that I can't really keep count. I forgot what it was filled to - 1800 psi, I think?It definitely isn't the cheapest way to pour a beer, but it is a nice touch to add to the serving of the beer. I now have 3 stout faucets, only one on the kegerator though, one on the jockey box, and then one spare (I used all three for serving at my wedding a year ago). If I ever expand my serving capacity, I will consider using more than just the single stout faucet. I've heard an Irish red on nitro is good.I haven't really added any new equipment to my brewery - though I have been adding schrader valves to my fermenters so I can pressurize them for transfers. So far I've added them to two buckets and a carboy cap.I've been thinking about getting another march pump and building a larger mash tun designed for fly sparging (I currently batch sparge), but the overall cost is prohibitive to me right now, and I want to save up to build a walkin cooler in a year or so.

[MtnBrewer]

One cubic foot is 7.5 gallons. Liquid CO2 at room temp has a density of about 6.5 lb/gal. 5# will occupy about 0.8 gallon.

So why wouldn't they fill the CO2 tank all the way up?

[gnef]

Yes, it is stored as pressurized liquid in the tank. I think what JKoravos is calculating is when all of that liquid CO2 is vaporized and is in gas form at STP, it will occupy 18.5 cubic feet. I haven't done the calculation, that is just what I am assuming he did (convert lbs to g, divide by molar mass, multiply by 22.4 L, convert to cubic feet). From there he just calculated the average volumes of CO2 that are in solution to find how many gallons/kegs a 5# tank could pressurize.

[MtnBrewer]

Yes, it is stored as pressurized liquid in the tank. I think what JKoravos is calculating is when all of that liquid CO2 is vaporized and is in gas form at STP, it will occupy 18.5 cubic feet. I haven't done the calculation, that is just what I am assuming he did (convert lbs to g, divide by molar mass, multiply by 22.4 L, convert to cubic feet). From there he just calculated the average volumes of CO2 that are in solution to find how many gallons/kegs a 5# tank could pressurize.

Ok, I thought he was saying that a 5# tank had 18.5 ft³ of volume. Let me go back and re-parse his last couple of posts. What I was trying to say is that in a freshly filled 5# tank, however much volume is in there is all liquid.

[denny]

How does one use a syringe? Do you pour the beer, then fill the syringe, then empty the syringe into the beer?

Pour a beer, then suck some of the beer up into the syringe. Then shoot it back into the beer, below the surface. Before Guinness used nitro, their beers came packaged with a syringe.

[ThroatwobblerMangrove]

Pour a beer, then suck some of the beer up into the syringe. Then shoot it back into the beer, below the surface. Before Guinness used nitro, their beers came packaged with a syringe.

what sort of syringe do you use? I've tried one that's intended for injecting meat a couple of times. it works okay but smaller holes might work better.

[3rd party JKor]

Ok, I thought he was saying that a 5# tank had 18.5 ft³ of volume. Let me go back and re-parse his last couple of posts. What I was trying to say is that in a freshly filled 5# tank, however much volume is in there is all liquid.

I was saying that the amount of gas you get out of a 5# tank is 18.5 cubic feet. I did exactly what gnef described to calculate that number.

[denny]

what sort of syringe do you use? I've tried one that's intended for injecting meat a couple of times. it works okay but smaller holes might work better.

I use a smallish one. Don't recall the exact size.

[ANUSTART]

No, I have a separate 80 cubic foot cylinder for the beer gas. As far as how much gas you get, a 5# CO2 tank has about 18.5 cubic feet of gas. So the 80 cubic foot tank actually has 20 cubic feet of CO2, only slightly more than 5# liquid co2 tank, but you typically carb beer gas beer less, maybe 1.5 volumes vs. 2.2 volumes for other beers.Using those number the volume of beer carbed with a beer gas tank compared to a 5# liquid tank is:(20/18.5)*(2.2/1.5)=1.6 times as much beer carbed with an 80CF beer gas tank.Of course, the biggest difference is that I only have one stout tap so it'll be something like a 5 to 1 ratio of normal carbed beers versus beer gas carbed. If you're ONLY carbing your beer, a 5# tank will carb 140 gallons of beer to 2.2 volumes. Of course, I do a lot more things than carb beer. I'm sure I blow through a lot of CO2 in purging and CO2 transfers. I won't be doing as much of that with the beer gas. My guess is the beer gas will last 10+ batches. That's likely 2 or 3 years of beer gas beer.

Why on Earth would one measure a compressible gas in terms of volume?

Yes, it is stored as pressurized liquid in the tank. I think what JKoravos is calculating is when all of that liquid CO2 is vaporized and is in gas form at STP, it will occupy 18.5 cubic feet. I haven't done the calculation, that is just what I am assuming he did (convert lbs to g, divide by molar mass, multiply by 22.4 L, convert to cubic feet). From there he just calculated the average volumes of CO2 that are in solution to find how many gallons/kegs a 5# tank could pressurize.

I was saying that the amount of gas you get out of a 5# tank is 18.5 cubic feet. I did exactly what gnef described to calculate that number.

I guess this makes sense, but I still question the logic behind stating the amount of gas in terms of volume. Mass seems like a much more appropriate way to state how much there is.

[gnef]

the usefulness of stating the amount of gas by volume is that is how we talk about levels of carbonation in our beers: 1.5 volumes, 2.2 volumes, etc. Using that, we can figure out how many gallons of beer we can carbonate using what size CO2 tank (this assumes no waste or the pressure to serve either).This is also how the industrial tanks are measured: I have an 80 cubic foot beergas tank like JKoravos, which is the largest I can get locally. To move up to 120 Cf, airgas said those were only possible to go to bars, they wouldn't even let me purchase one.

[chuck_d]

Why on Earth would one measure a compressible gas in terms of volume?I guess this makes sense, but I still question the logic behind stating the amount of gas in terms of volume. Mass seems like a much more appropriate way to state how much there is.

Volume @ STP is just as good as mass, all you need is consistent units. Beer gas I believe is sold by volume, not by weight, but it's been over a year since I picked some up. As for why JK converted in one direction and not the other, my guess is that it makes the math easier when you deal with a pure gas rather than a mixed gas.

[chuck_d]

the usefulness of stating the amount of gas by volume is that is how we talk about levels of carbonation in our beers: 1.5 volumes, 2.2 volumes, etc. Using that, we can figure out how many gallons of beer we can carbonate using what size CO2 tank (this assumes no waste or the pressure to serve either).This is also how the industrial tanks are measured: I have an 80 cubic foot beergas tank like JKoravos, which is the largest I can get locally. To move up to 120 Cf, airgas said those were only possible to go to bars, they wouldn't even let me purchase one.

Eh, careful with that. "Volumes of CO2" is not a measurement of volume, it's base units would be mass/volume, or grams/liter. 1 Volume of CO2 = 2 grams/liter of CO2. The volume in question in that unit is a relative volume. I'm not certain how I would take cu. ft. of CO2 and calculate carbonation levels in a straight forward way, but maybe I just have not thought it through.Let me see... let's forget cu.ft. and go with L, so I've got say 20L of CO2, and I want to carbonate at 2 Volumes, so I assume it's... 20L / 2 Volumes = 10 L/volume, see already my units are a little funky. Hmm, so I guess the implication is that I can carbonate 10L of beer at that level?Er, no... it should be like 20 L of CO2, 10 L of beer, = 2 volume of CO2 that I can carbonate too? I dunno, I'll have to think this through when I'm not on a train and drinking It might work, I've just never thought about it that way before.Edit: cuz 10 L/volume = 10 L^2/gram, I'll wrap my head around this at some point though.

[chuck_d]

Yeah, so you want CO2 on top, and beer on the bottom... we've got 100 L of CO2, and want to carbonate to 2 volumes... so,100 L of CO2 / X L of Beer = 2 Volumes of CO2X = 100 / 2 = 50 Liter of beer @ 2 Volumes, or...50 Liters of Beer, carbonated at 4 grams/L = 200 grams of CO2.200 grams = 100 L of CO2 at STP?If so it works, but this train Wifi is so bad I can't look up constants right now.1.97 g/L @ 1 atm & 0*C? Kind of sticks in my head200g / 1.97 g/L ~= 100 L, so yeah, looks like it works, if my constant is accurate. Dunno why I was trippin on this...

[3rd party JKor]

Eh, careful with that. "Volumes of CO2" is not a measurement of volume, it's base units would be mass/volume, or grams/liter. 1 Volume of CO2 = 2 grams/liter of CO2.

The way I've seen volume of CO2 defined is as the volume of CO2 at STP dissolved into the equivalent volume of beer. for example, 10 gallons of CO2 at STP dissolved into 5 gallons of beer is 2 volumes of carbonation. I've never seen the 2g/liter number.Although, 2 grams of CO2 at STP is 1.02 liters, so for all intents and purposes m/v and v/v are the same in this case.

[3rd party JKor]

Why on Earth would one measure a compressible gas in terms of volume?I guess this makes sense, but I still question the logic behind stating the amount of gas in terms of volume. Mass seems like a much more appropriate way to state how much there is.

STP is implied in the definition of volumes. Stating the volume of gas under a known temperature and pressure is the same as stating the quantity as a mass.

[chuck_d]

The way I've seen volume of CO2 defined is as the volume of CO2 at STP dissolved into the equivalent volume of beer. for example, 10 gallons of CO2 at STP dissolved into 5 gallons of beer is 2 volumes of carbonation. I've never seen the 2g/liter number.Although, 2 grams of CO2 at STP is 1.02 liters, so for all intents and purposes m/v and v/v are the same in this case.

Yeah, I don't know what my brain was doing... beer is cheaper on the train than in the city so that might have something to do with it. Sorry for all the sidetracking.

[ANUSTART]

STP is implied in the definition of volumes. Stating the volume of gas under a known temperature and pressure is the same as stating the quantity as a mass.

I guess I don't hang out around gassy people enough to know that STP is implied. Carry on.

[MyaCullen]

I use a smallish one. Don't recall the exact size.

I use one that i got at the farm supply down the road, it has a 1/2 inch pluger, does the trick nicely, just suck it half full of stout, and quickly discharge into the beer and watch the cascade action

[ANUSTART]

Then you need to start using units of kg or g instead of pounds.

I prefer slugs.

[3rd party JKor]

Only if you know the percent composition. Do you know the ratio of CO₂ to NO₂ in your beer gas?

It should be 25% CO2 and 75% N2.