How many kegs per CO2 cylinder?

[EnglishAndy]

I'm on my first 14lb CO2 cylinder and it's been about 13 months so far. In that time I've done 8 full size corny's and 3 half-size. All have been force carbed, dispensed and then the CO2 used again to push some PBW through the lines, water to rinse and some starsan to sterilise. I also use it to purge the headspace at 5x15psi pressurise/release cycles.

I weighed my cylinder and I'm 89% through it by weight. Does that sound about right? I feel I should be getting a refill before starting another corny.

 

[S-Met]

What is the psi remaining in the tank? I usually consider a tank empty at the 500lb point. Tank seems to be full most of its life, then suddenly fall to empty once it gets below 500.

To answer your other question, tanks last as long as they last. Too many variables to estimate. Force-carb technique, desired carb level, serving pressure, line length all factor into how long the tank will last.

My tanks seem to last forever, but I also naturally carb my kegs with sugar. Both to save CO2 and to help scavenge O2 in the headspace.

 

[Vale71]

I'm on my first 14lb CO2 cylinder and it's been about 13 months so far. In that time I've done 8 full size corny's and 3 half-size. All have been force carbed, dispensed and then the CO2 used again to push some PBW through the lines, water to rinse and some starsan to sterilise. I also use it to purge the headspace at 5x15psi pressurise/release cycles.

I weighed my cylinder and I'm 89% through it by weight. Does that sound about right? I feel I should be getting a refill before starting another corny.

First of all you're absolutely right in weighing your cylinder as that's the only way of gauging remaining capacity when dealing with liquid gas.
Here is a couple of pointers on how to estimate CO2 usage. I'll use metric as that's what I'm used to and will leave any conversion to you 'mericans.

1 kg of liquid CO2 will give you very close to 500 liters of gas at 1 bar pressure or 1.96 g per liter of gas at 1 bar. Lets estimate how many liters you need for a complete lifecycle for a 19 liter keg.

You need 15 times 19 liters of gas to purge at 1 bar, that makes a whopping 285 liters.
Let's say you need 3 g/liter of CO2 to force carb which is pretty standard for a top fermented beer, that makes 75 g or 29 liters.
Then you'll need an additional 38 (that's because 1 bar on the manometer is actually 2 bar absolute) liters of gas to serve the beer.

Our total is 285 + 29 + 38 = 352 liters of gas or 690 grams of CO2 per 19 liter keg, not including any you might use for washing and sanitizing the keg and lines. Your bottle should last you for fewer than 10 kegs.

As you can see the biggest slice of the pie is used up for purging the keg, you might want to consider liquid purging instead as it will mean great savings as far as CO2 is concerned.

 

[JONNYROTTEN]

You 90% through a tank that lasted over a year. Eat the 10% and spend $20 on a refill that will last another year...what are you losing $2 in gas.

When its convienent get it refilled soon as possible opposed to being forced to run out when you run out....thats never much fun

 

[EnglishAndy]

First of all you're absolutely right in weighing your cylinder as that's the only way of gauging remaining capacity when dealing with liquid gas.
Here is a couple of pointers on how to estimate CO2 usage. I'll use metric as that's what I'm used to and will leave any conversion to you 'mericans.

1 kg of liquid CO2 will give you very close to 500 liters of gas at 1 bar pressure or 1.96 g per liter of gas at 1 bar. Lets estimate how many liters you need for a complete lifecycle for a 19 liter keg.

You need 15 times 19 liters of gas to purge at 1 bar, that makes a whopping 285 liters.
Let's say you need 3 g/liter of CO2 to force carb which is pretty standard for a top fermented beer, that makes 75 g or 29 liters.
Then you'll need an additional 38 (that's because 1 bar on the manometer is actually 2 bar absolute) liters of gas to serve the beer.

Our total is 285 + 29 + 38 = 352 liters of gas or 690 grams of CO2 per 19 liter keg, not including any you might use for washing and sanitizing the keg and lines. Your bottle should last you for fewer than 10 kegs.

As you can see the biggest slice of the pie is used up for purging the keg, you might want to consider liquid purging instead as it will mean great savings as far as CO2 is concerned.

Thanks a lot for doing the math! I think I may not have been clear about the purge step though - it's done when the keg is full to purge the headspace not when the keg is empty so the volume being purged is much smaller - whatever is left when I fill to about a half inch below the gas-in tube.

 

[Vale71]

Thanks a lot for doing the math! I think I may not have been clear about the purge step though - it's done when the keg is full to purge the headspace not when the keg is empty so the volume being purged is much smaller - whatever is left when I fill to about a half inch below the gas-in tube.

My bad, I thought you were doing closed transfers and purged the keg beforehand.

 

[EnglishAndy]

You 90% through a tank that lasted over a year. Eat the 10% and spend $20 on a refill that will last another year...what are you losing $2 in gas.

When its convienent get it refilled soon as possible opposed to being forced to run out when you run out....thats never much fun

I think you're right. I'll give the gas supplier a call next week.

 

[S-Met]

Thanks a lot for doing the math! I think I may not have been clear about the purge step though - it's done when the keg is full to purge the headspace not when the keg is empty so the volume being purged is much smaller - whatever is left when I fill to about a half inch below the gas-in tube.

I don't know if its a proven arguement, but thats the reason I prime instead of force carb, unless I'm in a hurry. 2-3 weeks at room temp and I've got a charged keg that used all of the free oxygen. I think the extra time helps clear and clean the brew as well. Style dependent of course, probably not ideal for an IPA.

 

[Vale71]

2-3 weeks at room temp and I've got a charged keg that used all of the free oxygen.

Actually it used up hardly any measurable amount, so that's really not an argument.

 

[JONNYROTTEN]

I don't know if its a proven arguement, but thats the reason I prime instead of force carb, unless I'm in a hurry. 2-3 weeks at room temp and I've got a charged keg that used all of the free oxygen. I think the extra time helps clear and clean the brew as well. Style dependent of course, probably not ideal for an IPA.

"free" co2 is a none issue. A $20 tank last almost a year...by far the least expensive part of brewing. If ya cant swing $20 a year your in the wrong hobby...not even worth worrying about. Plus the beer is carbed in 24 hours with a tank...its a no brainer

 

[EnglishAndy]

I wonder if I had a small leak at some point? I took off and replaced a keg post o ring today and the old one had a few small dents in it probably where I struggled to get the disconnect off because the rubber had gone stiff in the cold keezer. Thing is, I read on the forum here that when you get a leak it's goodbye gas basically overnight.

 

[S-Met]

"free" co2 is a none issue. A $20 tank last almost a year...by far the least expensive part of brewing. If ya cant swing $20 a year your in the wrong hobby...not even worth worrying about. Plus the beer is carbed in 24 hours with a tank...its a no brainer

I don't believe I've made any mention of cost savings in my process. I have spoken to prefering the taste of naturally carbed beer. My assumption is it has extra time to clean and clear the beer. If I'm in a hurry, I can burst carb, but I just don't see a need most of the time. I'm not rushing to get my product on tap. If for some reason I was out, I would just open or buy a bottle.

I also mentioned a possible scrubbing of free oxygen during the conditioning. Again, I don't claim the argument is valid, just that its possible as fermentation is an aerobic process.

My process:
add priming sugar
fill keg from liquid post venting through prv or gas post.
Seal with CO2 through liquid out while purging through prv.
Set keg in temp stable area for 2-3 weeks.
Enjoy perfectly carbed beverage. 1st pint or 2 may be cloudy, but usually sparkling clear.

 

[JONNYROTTEN]

. I have spoken to prefering the taste of naturally carbed beer.

I didnt know naturally carbed beer tasted any different? How does it differ?
I've never naturally carbed

 

[bracconiere]

i carb, and push about 100 kegs a year on a 20# tank? 10 on 14lbs seems really low......when i drank a reasonable amount, a tank would last me 2-3 years...(and before i started using vasoline to lube the posts and poppits, a tank would last me 3 months)

If you weigh it on a scale look for the TW### stamp on the cylinder that will tell you how many pounds you have left (or kg, whatever)

 

[JONNYROTTEN]

i carb, and push about 100 kegs a year on a 20# tank? 10 on 14lbs seems really low......when i drank a reasonable amount, a tank would last me 2-3 years...(and before i started using vasoline to lube the posts and poppits, a tank would last me 3 months)

100 kegs on 20 pound tank....you're off the meth right?

 

[Vale71]

I also mentioned a possible scrubbing of free oxygen during the conditioning. Again, I don't claim the argument is valid, just that its possible as fermentation is an aerobic process.

You are kidding, right?

 

[S-Met]

I didnt know naturally carbed beer tasted any different? How does it differ?
I've never naturally carbed

I don't know how to explain. But if you can bottle, try and bottle 3-4 beers and force-carb the rest. Do a tasting, it just has a different taste.

Occasionally you can find commercial brews with both options. I think SNPA in a can is naturally carbed.
I theorize the added time for yeast clean-up, but there may be more appropriate explanations.

 

[S-Met]

You are kidding, right?

No, fermentation, at lest in ethanol production is aerobic (obligate or facultative anaerobes). Do you have unequivocal evidence proving otherwise? Please present non-anecdotal evidence.

 

[Carolina_Matt]

I have a 5lb tank. They've lasted about 12 batches per refill, give or take. That's with force carbing at about 30 psi for 2 days, then dropping down to 10 psi for serving. That's my only frame of reference.

 

[JONNYROTTEN]

No, fermentation, at lest in ethanol production is aerobic (obligate or facultative anaerobes). Do you have unequivocal evidence proving otherwise? Please present non-anecdotal evidence.

Wasnt this a question on final Jeopardy?

The answer was....What are big words nobody understands or uses

 

[day_trippr]

No, fermentation, at lest in ethanol production is aerobic (obligate or facultative anaerobes). Do you have unequivocal evidence proving otherwise? Please present non-anecdotal evidence.

You are as wrong as wrong can get and one could instantly obtain a bazillion "science-y" articles to prove it.
But let's keep it simple...

https://en.wikipedia.org/wiki/Ethanol_fermentation

Empirically/anecdotally, when I had a DO meter, after bring 11 gallons of wort to 12 ppm, it was close to zero ppm O2 6 hours post-pitch - ie, the reproduction phase (where O2 is important) had taken every last measurable bit of oxygen out of the wort...

Cheers!

 

[bracconiere]

100 kegs on 20 pound tank....you're off the meth right?

damn right! nothin' but homebrew these days! now instead of stealing from the bosses till, i just talk **** in homebrew forums....(actually i started heavy drinking back in '04 so....i haven't been an *******, and stealing for quite some time)

but yes i brew about 50 10 gal batches a year, and only have to swap my tank once a year, unless i get a leak...which is why i keep my tank on a analog bathroom scale, so i can catch them fast....

 

[bracconiere]

You are as wrong as wrong can get and one could instantly obtain a bazillion "science-y" articles to prove it.
But let's keep it simple...

https://en.wikipedia.org/wiki/Ethanol_fermentation

Empirically/anecdotally, when I had a DO meter, after bring 11 gallons of wort to 12 ppm, it was close to zero ppm O2 6 hours post-pitch - ie, the reproduction phase (where O2 is important) had taken every last measurable bit of oxygen out of the wort...

Cheers!

lol, oxygen is for acetobactor, not yeast....

 

[Vale71]

No, fermentation, at lest in ethanol production is aerobic (obligate or facultative anaerobes). Do you have unequivocal evidence proving otherwise? Please present non-anecdotal evidence.

I don't even know how to respond to such nonsense. May I suggest losing the arrogance and then reading up on the most basic topics in brewing?