40 replies to this topic

[Thirsty]

At 3 psi, which was plenty to move it, I bet I used less than the same amount to beergun a sixpack.

[Slainte]

I've just been using the CO2 to start the transfer, and let gravity do the rest of the work. Saves on CO2, and I don't have to worry about cracking a carboy.

[3rd party JKor]

According to Ideal Gas Law:PV = nRTP = 3 psig = 17.69 psia = 121968 Pa V ≈ 7 gal = .0265 m3R = 8.314 m3-Pa/mol-KT = 68F = 20C = 293Kn = (121968*.0265)/(8.314*293) = 1.33 mol * 44 g/mol = 58.3 g = 0.128 lbmat 3 psig 0.128lbs of CO2 will be in the carboy. Some of it was there to begin with, but most was added. Divide it by 5 and you find that one transfer will use about 2.5% of a 5 lb cylinder.

[DubbelEntendre]

According to Ideal Gas Law:PV = nRTP = 3 psig = 17.69 psia = 121968 Pa V ≈ 7 gal = .0265 m3R = 8.314 m3-Pa/mol-KT = 68F = 20C = 293Kn = (121968*.0265)/(8.314*293) = 1.33 mol * 44 g/mol = 58.3 g = 0.128 lbmat 3 psig 0.128lbs of CO2 will be in the carboy. Some of it was there to begin with, but most was added. Divide it by 5 and you find that one transfer will use about 2.5% of a 5 lb cylinder.

Are you telling me that all that stuff I learned in college is actually useful?I approve in this instance.

[stangbat]

According to Ideal Gas Law:PV = nRTP = 3 psig = 17.69 psia = 121968 Pa V ≈ 7 gal = .0265 m3R = 8.314 m3-Pa/mol-KT = 68F = 20C = 293Kn = (121968*.0265)/(8.314*293) = 1.33 mol * 44 g/mol = 58.3 g = 0.128 lbmat 3 psig 0.128lbs of CO2 will be in the carboy. Some of it was there to begin with, but most was added. Divide it by 5 and you find that one transfer will use about 2.5% of a 5 lb cylinder.

Funny this is almost the same as what I calculated (I got 0.15 lb using 70 degrees and atmospheric pressure). However, I started doubting myself because I then used what I calculated to work backwards and see how many corny kegs you could carbonate and dispense and the numbers seemed wrong. (I used 2.5 volumes of CO2 for carbonation + 1 volume for dispensing). I was getting that a 5 lb tank would carb and dispense 25 corny kegs and even under ideal conditions that seems way too high. However I now think I realize one of my errors, I was not taking into account the pressure in the keg when carbonating, I was still using atmospheric pressure. So I didn't post my calculations since I wasn't sure.I will say that one time I weighed my tank before and after pressure racking 10 gallons. Unfortunately I didn't write down the amount of CO2 used. But I do remember being surprised how little it was. I'm fairly certain that it was in the range we calculated, and certainly not more than 0.25 lb.

[stangbat]

Are you telling me that all that stuff I learned in college is actually useful?I approve in this instance.

I've often thought that if college coursework was directly tied to brewing, people would pay a lot more attention. Thermodynamics would have been much more interesting. Fluid mechanics would have been much more fun. Statics, strengths of materials, structural analysis, steel design...I would have learned so much more if beer was involved. I still would have hated dynamics though.

[stellarbrew]

I've often thought that if college coursework was directly tied to brewing, people would pay a lot more attention. Thermodynamics would have been much more interesting. Fluid mechanics would have been much more fun. Statics, strengths of materials, structural analysis, steel design...I would have learned so much more if beer was involved. I still would have hated dynamics though.

Another ME, or are you a CE?

[djinkc]

I've often thought that if college coursework was directly tied to brewing, people would pay a lot more attention. Thermodynamics would have been much more interesting. Fluid mechanics would have been much more fun. Statics, strengths of materials, structural analysis, steel design...I would have learned so much more if beer was involved. I still would have hated dynamics though.

I didn't know you were an accountant.

[3rd party JKor]

Are you telling me that all that stuff I learned in college is actually useful?I approve in this instance.

Crazy stuff, eh?

Funny this is almost the same as what I calculated (I got 0.15 lb using 70 degrees and atmospheric pressure). However, I started doubting myself because I then used what I calculated to work backwards and see how many corny kegs you could carbonate and dispense and the numbers seemed wrong. (I used 2.5 volumes of CO2 for carbonation + 1 volume for dispensing). I was getting that a 5 lb tank would carb and dispense 25 corny kegs and even under ideal conditions that seems way too high. However I now think I realize one of my errors, I was not taking into account the pressure in the keg when carbonating, I was still using atmospheric pressure. So I didn't post my calculations since I wasn't sure.I will say that one time I weighed my tank before and after pressure racking 10 gallons. Unfortunately I didn't write down the amount of CO2 used. But I do remember being surprised how little it was. I'm fairly certain that it was in the range we calculated, and certainly not more than 0.25 lb.

One problem is that the beer already has CO2 in it, maybe like 1.5 volumes. So that would throw off your calc. I'd have to work the numbers, but 25 doesn't sound too crazy for a 5 pound tank. Look at it this way, 5 lbs of CO2 is 51.5 moles. At atmospheric pressure, that's 1,239 liters, or 327 gallons, of gaseous CO2. One "volume" of CO2 for a 5 gallon keg is 5 gallons of atmospheric pressure CO2, so there are 65.4 volumes of CO2 in a 5lb tank (with respect to a 5 gallon keg). Divide that by 25 kegs and you get 2.62 volumes per keg. Then add the 1.5 volumes that is dissolved into the beer during the fermentation process and you get 4.12 volumes of CO2 'used' per keg. That sounds reasonable to me.

[stangbat]

Another ME, or are you a CE?

CE.

One problem is that the beer already has CO2 in it, maybe like 1.5 volumes. So that would throw off your calc. I'd have to work the numbers, but 25 doesn't sound too crazy for a 5 pound tank. Look at it this way, 5 lbs of CO2 is 51.5 moles. At atmospheric pressure, that's 1,239 liters, or 327 gallons, of gaseous CO2. One "volume" of CO2 for a 5 gallon keg is 5 gallons of atmospheric pressure CO2, so there are 65.4 volumes of CO2 in a 5lb tank (with respect to a 5 gallon keg). Divide that by 25 kegs and you get 2.62 volumes per keg. Then add the 1.5 volumes that is dissolved into the beer during the fermentation process and you get 4.12 volumes of CO2 'used' per keg. That sounds reasonable to me.

Cool, makes more sense. Thanks for posting that.

[3rd party JKor]

Of course, that's theoretical. It doesn't take into account all the leaks in your system.

[dapittboss]

Of course, that's theoretical. It doesn't take into account all the leaks in your system.

Hey JK, I thought you were a professional football player. Maybe you are. All the quantum mechanics, thermodynamics and statistical mechanics I learned in college stayed back on campus. All those labs and I have never used any of it! But it's nice to see some physics applied to brewing.

[3rd party JKor]

Hey JK, I thought you were a professional football player. Maybe you are. All the quantum mechanics, thermodynamics and statistical mechanics I learned in college stayed back on campus. All those labs and I have never used any of it! But it's nice to see some physics applied to brewing.

I'm well rounded.

[BrewerGeorge]

I'm a little late to the party, but what the hell.I do all of my transfers with CO2, and I've actually got things rigged now so that I never have to lift anything full. (An empty Better Bottle goes into the ferm freezer and wort is pumped directly into that. The serving fridge is right next to the ferm freezer and the transfer hoses are long enough to reach between them.)The orange carboy cap fits the BB's. I use a stainless keg diptube and a hose clamp for the liquid side, and I've got these really cool polycarb twisting QD's for the gas side. (I use those for the entire gas side, actually.)The process is to fill the destination keg fully with iodophor and push it out into a bucket (or the next keg to be filled if I'm doing more than one) then lift it into the serving fridge after it's empty. Hook up the carboy cap on the BB, open the relief valve on the keg and start the gas. Everything is on the same level and 3-4 psi pushes 5 gallons in around 7 minutes. Even with displacing essentially 10 gallons each time, my 15lb CO2 canister seems to last about a year (20-30 batches) between refills.

[Kremer]

I'm no help on the CO2 push. I have spigots on my fermenters and gravity drain from them via a jumper hose with a liquid ball lock fitting directly into a purged and sealed keg.

[DubbelEntendre]

Anyone do closed transfers by pulling the beer out with a pump?

[stangbat]

Anyone do closed transfers by pulling the beer out with a pump?

The problem I see with this is that it really wouldn't be a closed transfer. If you pull liquid out with a pump, you need to let air in to replace the liquid.

[macbrak]

Pumps are probably more trouble then there worth for this much beer. The lhbs wine section usually sells something for this if you are interested.I don't closed transfer but syphon start with one of those mini keg chargers. I use a carboy hood or a bucket lid with two drilled holes.

[Thirsty]

Back to the drawing board. My primary-2ndary transfer was smooth, the carboy cap fit the primary snug. However while waiting for a mash on saturday I decided to xfer to keg 2 kolschs from glass 5 gallon carboys. The purple carboy cap does not fit these, and the orange does, but not real snug. Any pressure to push was just popping the cap off the carboy, making it a huge PITA. So I will probably need to work on a 2 hole rubber stopper setup, or a ring clamp of some sort. Any other ideas?

[MtnBrewer]

Back to the drawing board. My primary-2ndary transfer was smooth, the carboy cap fit the primary snug. However while waiting for a mash on saturday I decided to xfer to keg 2 kolschs from glass 5 gallon carboys. The purple carboy cap does not fit these, and the orange does, but not real snug. Any pressure to push was just popping the cap off the carboy, making it a huge PITA. So I will probably need to work on a 2 hole rubber stopper setup, or a ring clamp of some sort. Any other ideas?

Try a different cap? I do 2ndary-to-keg transfers all the time and have never had a problem with the cap blowing off unless I forgot to pull the pressure release on the keg.