Re: [SPHBC Public] keg testing?

Wow! Fabulous detailed answer Jim! A great primer for anyone getting started on kegging! - Al "Jim L. Ellingson" To: Sphbc(a)sphbc.org &lt;jellings(a)me.umn cc: .edu> Subject: Re: [SPHBC Public] keg testing? Sent by: Sphbc-admin@sphb c.org 07/08/2003 11:50 AM Please respond to Sphbc Quoting Steve Fletty &lt;fletty(a)umn.edu&gt;: Hi Steve, Kegs are great. Pressure testing is done w/ water. Water is incompressible therefore much safer if a "pressure vessel" should fail under pressure. Way too much "potential energy" w/ compressed gas. Leak testing is different. You might "fill" the keg w/ water, and then apply the pressure. That will save on gas. I use a squirt bottle of water to test for leaks. Soap sln would also work, as would iodophor sln. Spray around all the fittings, seals, and the pressure release valve. Most common leak will be at the gas inlet valve, especially if it's been dinged or damaged. I "leak test" my gas fitting each time I apply/remove CO2. I leak test the fittings after each fill. Soda kegs will not seal at low pressure, and may not hold a seal at low (less than 5 psi) pressure. "Priming" a keg w/ sugar can be tricky. I did it for a while, but quickly switched to force carbonation. Here's an example of how force carbonating might work. I don't like to leave my CO2 on, connected. So when I fill my kegs I leave some headspace. E.g. If I have 2 qrts of head space, and I pressurize to 60 psi (14.7 psig = 2 volumes = 1 gallon, 30 psi = 2 gal, 60 psi = 4 gallons of CO2 in the head space), I have about 4 gallons of CO2 in the head space. I need 9-13.5 gallons if I have no CO2 in the beer (unlikely) to achieve 2.0 - 3.0 volumes of CO2. In time, that CO2 will dissolve into the liquid until "equilibriam" is reached. (per the chart of Temp vs Pressure vs volumes of CO2.) How long does it take? Good question. It can take a while. How do I know/measure the pressure in my keg <Pkeg> (and therefore the volumes of CO2 in the liquid)? Assuming the volume of the headspace is much greater than the volume of your CO2 system, and the keg is at equilibriam, you can do the following. Pressurize CO2 system so some value greater than Pkeg. Close the CO2 bottle. Attach CO2 system to keg. CO2 will enter the keg until Pco2 = Pkeg. E.g. I think my keg's at 8 psi. So I charge my co2 system to 15 psi, and then close the CO2 bottle. When I attach the CO2 to the keg, my regulator will drop down to the keg pressure (8 psi.) If you heat sanitize the lid in a pan of boiling water, you will also soften the big-dawg o-ring. I "seat" my kegs at max pressure. Ball and pin lock cornelius kegs are rated at 110 psi. Sankey (aka Bud) kegs are rated at 60 psi. Your beer regulator may only go to 35 psi, which is both adequate and safe. Cold liquids carbonate faster, easier, at lower pressures. If you're in a real hurry, you can agitate th keg. Take care to not get any beer in th CO2 line. Other first time problems. Foamy beer. Generally too much pressure. Possibly too warm or over-carbonated. 32^F liquid holds it's gas very well (e.g. for bottle filling). 60 degree F liquid is very eager to out-gas. You want about 2 psi across the tap at a flow rate of about 1 oz per second. 4 to 6 ft of 3/16 ID plastic tubing should get you 10 or so psi drop. If your carbonation chart says you want/need 12 psig to get 2.5 volumes of CO2 at your fridge temp of 42 degrees F (from memory, no idea if these are close), then you're in great shape. I hope this helps, YMMV. I've got some other info on line, but I can't get to it from here. Cheers, Jim Jim Ellingson, Ph. D. jellings(a)me.umn.edu 1569 Laurel Ave., St. Paul, MN 55104 651-645-0753 Great Lakes Brewing News _______________________________________________ Sphbc mailing list Sphbc(a)sphbc.org http://truthbrew.com/mailman/listinfo/sphbc_sphbc.org