Post-mix kegs are the kegs used in most systems, made of stainless steel with a hatch cover for quick cleaning and filling. They have valves for gas in and beer out, and a safety release valve. The size of these "kegs" types varies from as small as 9 to 50 liters. The most popular is 18 liters and 22 liters, suitable for home brewer as they have a regular brew.
A few different forms exist, pin lock and ball lock (snap lock). We supply ball locks in stainless steel and plastic and operate on the same concept as your regular garden hose fittings, click on them and click off to quickly attach and remove the beer and gas lines from the keg.
CO2 GAS BOTTLE:
The gas bottles come in different sizes. The "D" size bottle is the most popular and the simplest to treat. They are slightly taller than knee height and weigh less than 20 kg. There are many sizes available but it can be very bulky and difficult to push, let alone unsightly. Gas bottles are available for hire from among others BOC Gases or Air Oil. Bottle hire is pricey, typically about $160 a year plus petrol, and that's the program you have for every year. Keg King makes a 6 kg Gun, an Australian licensed bottle available for around $300.00 from most homebrew stores. Like most gas stations they can be filled but first you should consult with your nearest gas dealer. Some Homebrew shops run the program for bottle exchange or refill the bottles to you!
A full CO2 bottle will hold an estimated pressure of 800 psi (pounds per square inch) of 5600 kpa, which is a little more than the 10 psi/70 kpa required to operate this system, so a regulator is a must.
The regulator screws onto the bottle of gas and reduces the pressure to safe levels. The regulator has two gauges, one for gas bottle pressure and the other for keg working pressure. The CO2 in the bottle begins as a liquid and the gas pressure in the bottle's headspace would be between 700 and 800 psi (5000-5600 kpa) depending on the bottle 's temperature.
Only when all of the liquid is gone does the high-pressure gauge on the regulator start to fall.
The easiest way to measure how much CO2 is left in the bottle is by weight not heat, so get a habit of measuring the bottle when you get it first. When empty the bottle is weighed and stamped.
PREPARING THE FRIDGE:
The kegs would need to stay cold like bottled water. For a regular keg containing a full batch of beer and being much larger than a bottle the fridge may need to be changed to fit the kegs, you will need to remove some or all of the shelves, and you may need to level the foundation as well.
Some older fridges at the bottom are not level and will need to be leveled. Using whatever best suits, you.
To bring the regulator gas line into the fridge, you'll need to drill a small hole. It's up to you whether you choose the side of the fridge or the back.
NB: Make sure all power is turned off before drilling.
Try to use a drill bit just large enough to suit the gas line snugly through the hole. Until sealing the gas line make sure the length of the line is adequate to reach out of the fridge.
NB: The wiring and cooling systems vary from refrigerator to refrigerator so be careful when drilling any holes in your refrigerator.
If your keg system has a beer gun it is only a matter of cutting the beer line to a length that fits you and adding the gun to one end of the line and disconnecting the beer to the other end of the line. The length of the line will range from 1.5 to 2 meters.
If you choose to have a tap, you'll need to drill more holes. Take care at drilling, as stated above. Again, the tap position is your preference. When you put the tap on the fridge door, make sure there's enough line of beer to allow the door to be opened completely.
If you decide to put the tap on the door, the interior of the door may collapse when you tighten the back nut. We noticed a small length of PVC pipe pressed over the tap shank allowing the tap to be tightened so that it is secure, without damaging the inside.
FILLING THE KEG:
The beer is fermented in the normal way. The time to clean and sterilize the keg is the day before fermentation is complete. Some of the liquid sterilizers sold in Homebrew shops can be used the same way you can sterilize your bottles. The easiest way to do this is to fill the kegs with water and liquid sterilizer 3/4, keep the lid in place and fill it with gas (40 PSI or 280 KPA) allowing the gas pressure to seat the lid in place and then clip the lid down. Turn the keg upside down for about 4 hours, and let the sterilizer get into the top of the keg fittings.
If bacteria grow this is the most likely spot. Then turn the keg upright, and continue to clean the keg 's bottom for another 4 hours. Once the gas is released complete, pour the sterilizer out and rinse with clean water.
The movement of the beer to the keg is as easy as racking straight into the keg through a piece of transparent sterilized tubing, cut to length such that it hits the bottom of the keg from the fermenter 's handle.
You'll find a line extending from the top of the keg to the bottom core of the keg. It is called the Drip Pipe, that's how it pulls the beer from the keg. There is another tunnel, too, which is very short in length. This is the inlet of Co2, in which the Co2 is injected into beer.
Your keg should be filled in from the bottom of this tube to about 12-25 mm (1/2 to 1 inch).
Now the keg is full remove the hatch cover and switch the keg to the refrigerator. When the gas line is cut to length it will be long enough to stretch beyond the refrigerator so that you can attach it to the gas bottle.
Turn on the gas bottle and set regulator pressure to 40 PSI or 280 KPA, keep the cap in place and attach the gas line to the keg. Allow the gas pressure to close the keg, then clamp the lid down.
What we need to do now is wash air out of the keg's headspace and replace it with CO2. This is done to prevent oxidization of the beer. The CO2 flows into the keg by lifting the pressure release valve, and the air flows out through this valve. This is called burping the keg and in half a dozen fast bursts is better handled.
The absorption of CO2 into your beer can depend on many things, most notably on the beer 's temperature, the pressure at which it is applied and the length of time pressure.
The CO2 will be consumed at a higher rate when the beer is cold (the beer does not absorb gas at room temperature as well) and if you consistently add 40 psi (280 kpa) for 36-48 Hours at usual cooling temperature the beer will be ready to try.
We find that the proper carbonation is given by two days at this strain. Based on your own preferences, there might be some trial and error to figure out what's best for you, for example. You may choose a lower carbonation rate for an English style Bitter but, on the other hand, you should make a German Weizen which would be more effervescent, so that the carbonation rate is up to you again.
A short cut to this cycle that we find works very well and is reliable is to burp the keg as mentioned and then lay the keg on its side with the gas post on the top side while the gas line is attached and the pressure is set at 40 psi (280kpa). Move the keg back and forth aggressively with your foot and you will begin feeling the gas pouring into the keg.Keep this process going until you can't hear any more gas going into the keg.Go and have a drink (about 5 minutes), and repeat. Keep doing so on and off for about 30 to 40 minutes. You should note at this point that when you rock it you can't feel any gas flowing into the keg which would mean the keg is gassed.
For use this system, you'll need to make sure you've got a long gas line, about 2 meters out and you can gas the keg outside the fridge. After the keg is gassed, if you do not have the space for the fridge, you can either put it in the fridge or outside.
Now for the nice part the beer pulls first.
Reduce the keg from carbonating pressure to pressure dispenser first. Do this by turning down the set screw on the controller, if the pressure does not drop as you turn the screw, you may need to use the safety relief valve to release the excess pressure. A recommended pressure to dispense is 10 psi/70kpa.
While the beer you kegged might have been obvious, you'll always get a payout at the bottom of the keg and the first bottle might not be what you 'd expect. We recommend that you pull out a few glasses before they clear. Whether you're using a gun or a tap always dispense with it completely open, you'll end up with all the froth and no beer when its part way opened.
Dispensing like carbonating can be trial and error, you'll see your mistake after plenty of action!
You've come a long way from the teaspoon of sugar in a long neck after building a keg device in your own home and it will give you many years of enjoyment. Multiply psi x 7 = kpa to translate Psi to kpa.