About CO2 Gas
CO2 safety is absolutely critical with a home Kegerator because in its pure form, CO2 is a poisonous gas. Also, pure CO2 is heavier than air and it tends to settle in low spots until disturbed. But CO2 is perfectly safe as long as you follow four simple safety rules.
CO2 Safety Rule #1 - Make sure you have a leak free system.
All kegerators have a gas or CO2 side and a liquid or beer side. Leaks in the beer side are obvious – you will have beer everywhere. But CO2 leaks can go un-noticed because the CO2 gas is odorless and colorless. The best way to test for a CO2 leak is to open the CO2 tank valve, make sure your regulator is set to the pressure you want then completely close the CO2 tank hand valve. Walk away and come back 2 minutes later. If your CO2 regulator low pressure gauge is still pointing to the same pressure you set the regulator to, you have a leak free system.
CO2 Safety Rule #2 - Keep your CO2 tank upright.
Always keep your CO2 tank upright when dispensing CO2. Full CO2 tanks are partly filled with liquid CO2 and partly filled with CO2 gas and CO2 regulators are designed to regulate CO2 gas only. Lay your CO2 tank on its side and you risk flooding your CO2 regulator with liquid CO2. This can cause your low side pressure to spike and the excess CO2 to vent through the pressure relief valve on the regulator or keg coupler. It is perfectly safe to lay your full CO2 tank on its side to store or transport as long as you are not using it while its laying on its side.
CO2 Safety Rule #3 - Keep your cool.
Whenever you have your CO2 tank filled or exchanged you should always drive straight home. The inside temperature of your car can easily reach 120 degrees F in the summer and long before your CO2 tank reaches this temperature the safety disk will burst, blowing all of the CO2 out of your tank and into the passenger compartment of your car! This would not be a fun experience while driving down the highway. Also, never stand your CO2 tank near a radiator, space heater or other heat source in the house.
CO2 Safety Rule #4 - Do not knock the tank over
If placing your CO2 tank outside your Kegerator, make sure its not in a high traffic area or anywhere it can easily be knocked over. CO2 tanks that fall over always fall on and clobber the regulator high pressure gauge because the regulator is the heavy side of the tank. 99% if the time you'll just damage the gauge and not cause a leak but every once in a while a damaged high pressure gauge will start leaking.
Standard CO2 Tank Sizes
Non-liquefied gases like nitrogen are sold in cubic feet but because CO2 gas turns into a liquid when it's compressed, CO2 is sold by the pound. One pound of CO2 in liquid form is the exact same amount of CO2 as one pound of CO2 in gas form and one pound of CO2 is about 7 cu ft. of CO2 gas at sea level.
The most common CO2 tank sizes are 5 pound 20 pound.
If you have the space for a 20 pound CO2 tank you should buy a 20 pound Co2 tank because the fill cost difference between a 5 and 20 pound tank is only $10 - $15. A good compromise is to get two 5 pound Co2 tanks and rotate them out so that you never run out of CO2 gas for your Kegerator.
Less common sizes are 2.5 pound, 10 pound and 50 pound tanks.
Most low cost home kegerators come with 2.5 pound CO2 tanks. They use this size because it fits well, but the cost to refill or exchange a 2.5 pound CO2 tank is about the same as the cost to refill or exchange a 5 pound CO2 tank. If possible you should exchange your 2.5 pound CO2 tank for a 5 pound or 20 pound tank even if you have to place the tank outside your Kegerator.
10 pound CO2 tanks are so uncommon that some gas supply and welding shops don't carry them and 50 pound CO2 tanks are too heavy for the average homeowner to manage.
Beer carbonation is measured in volumes of CO2. With 1 volume of CO2 carbonation the amount of CO2 dissolved in the beer would equal the same volume as the beer. Most commercial beer is carbonated to around 2.5 volumes of CO2, and a full keg of draft beer would contain just short of 5 cu ft. of CO2 gas.
14.5 gallons = 1.938 cu ft. and 1.938 cu ft. X 2.5 volumes = 4.845 cu ft. of CO2
What pressure should I set my regulator to?
Distributors will tell you that draft beer should be served at 12 PSI and in a perfect world this is correct because 12 PSI is also the ideal pressure to maintain carbonation in your keg. But this is also assuming you have a balanced system & most home kegerators are not balanced. Because of this most home kegerators server better at 9 - 10 PSI.
If your Kegerator also serves best at 9 - 10 PSI or even a lower pressure and your beer keg tends to go flat over time the solution is to occasionally crank your CO2 regulator up to 30 - 40 PSI for an hour or so to re-carbonate your beer. Then drop your pressure back down and bleed the excess pressure of your keg before serving.
How many Kegs will my CO2 tank Serve?
The "experts" will tell you that it takes about 1/2 lb. of CO2 to dispense a 1/2 bbl. of beer. A 2 1/2 lb. CO2 cylinder should dispense between 4-5 1/2 barrels or 8-10 1/4 barrels. A 5 lb. CO2 cylinder should dispense between 8-10 1/2 barrels or 18-20 1/4 barrels.
But I can come up with a more exact answer based on your regulator pressure setting, assuming you have no leaks!
1 pound of CO2 = 7 cu ft. at sea level, and sea level is at 14.7 PSI give or
take a little.
Here are the number of kegs served at each pressure setting, rounded down to the whole keg
What is my CO2 high pressure gauge telling me?
Not much really, but let me explain.
As long as there is liquid in your CO2 tank your high pressure gauge will read the exact same pressure based on temperature. This is because the pressure you read on the gauge is the pressure needed to keep the liquid in your CO2 tank, any volume of liquid, as a liquid. This means that for most of your CO2 tank's life your high pressure gauge will read exactly the same! And because what your high pressure gauge is displaying is dependent on temperature the gauge will display very low pressure if you place your CO2 tank in your kegerator. In most cases a CO2 regulator will display about 550 PSI as long as some liquid is left in the tank but all of your CO2 is still in there! To prove this just move your tank and regulator back outside your fridge and watch the high pressure rise as the tank warms up.
But your high pressure gauge will start to drop as soon as the last of the liquid CO2 is gone. So, watch your high pressure gauge. As soon as the pressure starts to drop it's almost time refill or exchange your CO2 tank.
Is it better to fill or exchange a CO2 Tank?
All depends - in some areas exchange is the only option.
There is no CO2 quality difference between a exchanged or refilled tank. If you exchange they are going to hand you a full CO2 tank that's been filled with the same CO2 gas they would refill your tank with. So for convenience sake it's easier to exchange. But if you bought your CO2 tank new then it's best to have it refilled because you know what's been in the tank for its entire life.
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