Kegging and Carbonating Your Beer
Kegging your beer and 'Force Carbonating'
Once you've fermented your beer and it's had a chance to settle, it's time to transfer it into vessels. This guide will cover the use of kegs, and using a CO2 cylinder to force Carbon Dioxide into the beer or 'Force Carbonating' the keg as it is otherwise known. This method is quicker than naturally carbonating the beer because it doesn't rely on a second ferment to produce the CO2, it literally forces the CO2 into the solution in a short period of time - the time itself depends on how much of a hurry you are in. It can be completed in as little as 30 minutes, or over a week depending on your preference. The potential down side to using these methods is that it is possible to get it wrong and over-carbonate the beer, resulting in you getting nothing but foam out of the tap. This can usually be remedied, but it takes time and is not much comfort to you if you have the lads on their way over to watch a game in an hour....so some care is required if the desired result is to be achieved.
- CO2 bottle with regulator, beer/gas line and 'gas in' disconnect
- Beer tap with beer/gas line and 'beer out' disconnect.
- Serving fridge.
- Un-carbonated beer (finished ferment)
All force carbonation needs to take place with the beer already chilled - preferably in the fermenter if possible. We ferment our beers in a fridge fitted with a digital controller to over-ride the thermostat and maintain an ideal stable ferment temperature, and at the end of the ferment we 'crash chill' the whole fermenter simply by dialing down the desired temperature with the controller. This has the effect of causing the yeast to drop out of solution to the bottom of the fermenter, which is important because if it doesn't drop out in the fermenter, it will drop out in the keg causing you to pull cloudy beer from the keg for at least the beginning of, and sometimes all of the keg. So we recommend the use of a ferment fridge to make this process easy and predictable. Depending on your fridge model (fridge on top), it can also be convenient to rack your beer into the keg using gravity, without even removing it from the fridge - which means you don't need to lift or move it & won't disturb the yeast cake prior to racking.
Remember to loosen off the fermenter lid/remove the airlock BEFORE YOU START TO RACK IT OFF so you don't suck the contents of the airlock into the fermenter and contaminate your beer!
When you begin to rack the beer, start the flow out of the fermenter quite quickly initially, allowing the first 200ml or so to run out into a jug with the yeast that will most likely be in it and then slow the flow down to prevent it continuing to pull yeast from the bottom of the fermenter. Pay attention to the last little bit at the end of racking as the beer level approaches the yeast cake - turning it off before the yeast starts to get pulled through into the line. This will avoid the majority of the yeast going into the keg, and makes for a cleaner brighter tasting beer with a longer life.
The slow method will still work if the beer goes into the keg at ferment temperature, however warm liquid does not absorb CO2 as readily as it does when it is cold, so the faster methods will not work very well until the beer is cold. If you wish to use the faster methods and can't chill the beer in the fermenter, rack your beer into the keg and place it into the serving fridge overnight. It will be ready to fast carb once it is at serving temperature.
For all methods
- Crash chill your beer in the fermenter
- Clean and sanitise your keg, purge the keg with CO2 from the gas bottle to remove oxygen, by opening the lid and connecting the gas line to the keg. (Failure to do this can result in oxidisation of the beer, something that will affect taste and shelf life)
- Carefully rack your beer into the keg, taking care to get as little yeast into the keg as possible. If the beer is unsatisfactory cloudy, this is a good time to filter the beer as it goes into the keg - cold beer filters particularly well (please see the 'filtering your beer' guide). Excess yeast into the keg will result in cloudy beer into the glass.
- Close up the keg, and pressurise the keg to about 10psi, and check for gas or beer leaks. You want to find these now before they become an empty keg, or gas bottle.
- From this point follow your preferred method.
- Put the keg in the fridge, connect the gas and adjust the pressure to about 11psi.
- Wait for 7-14 days, checking the carbonation from about the 7 day point. Once it reaches your preferred level of carbonation you can adjust it to your serving pressure and drink.
BBQ this weekend
Follow the steps 'for all methods', and;
- Connect your keg, adjust the regulator to 30 psi.
- Lay the keg on it's side and roll it back and forth for a few minutes until you no longer hear gas bubbling into the keg.
- Stand the keg up, disconnect from the gas and put into your serving fridge overnight or about 8 hours.
- Relieve any excess pressure in the keg, reset the regulator to about 15 psi and leave the keg connected to the gas.
- Check for your desired carbonation level in roughly 24 hours, if it's not there yet re-pressurise to 10-15 psi and check again in 24 hours - repeat as required until you get your desired carbonation. The keg can then be re-adjusted to serving pressure and consumed.
Party tonight, no beer!
- Follow the 'BBQ this weekend' method steps 1 & 2, but instead of leaving the keg overnight, GENTLY relieve the pressure in the keg and check the level of carbonation after 2 hours. If it's where you like it, you're good to go - if not repeat steps 1 & 2 and try again in a couple of hours.
BBQ in an hour method.
- Adjust your regulator to 60 psi (400kPa)
- If this is your first time using this method, say a prayer to the beer gods.
- Connect your keg and allow gas to flow in and then follow one of two methods;
- Method a) Allow the gas to flow into the keg @ 60psi until it will accept no more, disconnect the gas, shake the keg vigorously for 5 minutes. Repeat this until no more gas will flow into the keg. Disconnect from the gas and place the keg back in the fridge for 15 minutes, carefully relieve excess pressure and check carbonation level. Repeat if required.
- Method b) Allow the gas to flow into the keg @ 60psi, and with the bottle still connected, and CAREFULLY - vigorously shake the keg from a vertical to horizontal position 25 times whilst allowing the gas to continue flowing. DO NOT use this method if you do not have a one way or 'non-return' valve fitted between your regulator and your keg, as any flow back for any reason into your regulator can damage it. Disconnect the gas, place the keg back in the fridge and leave to settle for 30 minutes. Relieve excess pressure, adjust the regulator to your desired serving pressure and check the carbonation level. If it's not quite there yet, repeat the process in steps of 10 shakes, as this method can easily result in overcarbonation of your beer.
Caveat - Both of the methods described in the 'BBQ in an hour' method can easily overcarbonate your beer, so use at your own risk. I have had great success over the years with method b, however everyone's 'keg shake' is different so it may take some practice and adjustment to achieve your preferred level of carbonation using these methods. A good idea (as with all things brewing) is to take notes so you can adjust to get your method spot on and then use the same steps each time in the future.
Last but not least - disaster has struck......what now?
"ARRRGGGHHHHHH! Whenever I pour a beer, it foams uncontrollably whilst pouring, but is 'undercarbed' or flat in the glass........what's happening?"
Your beer is 'over-carbonated', or has too much gas in solution and cannot hold it all. When you open the tap, the difference in pressure between inside the keg (which is effectively preventing the gas from coming out of solution) and the normal atmospheric pressure outside the keg when it makes it out into the glass, is too great - and the majority of the CO2 will come out of the liquid in a hurry causing the beer to foam during the pour, resulting in a flat beer. An example of this is opening a bottle of fizzy drink too quickly - the shock change in pressure cause the drink to degas quickly.
But don't worry, if you've managed to over carb your beer, all is not lost. If it's only a little bit overcarbed and not so much foaming from the tap but still more highly carbonated in the glass than you prefer, simply pour a few beers with a gas turned off. It will slowly adjust as you pour beer and the gas is not replaced. Turn the gas back on and adjust your serving pressure to suit once the level of carbonation has dropped to where you prefer.
Seriously overcarbed beer that is pouring foam and flat in the glass needs to be 'de-carbed' by having the pressure released gradually. This can either be done over time by gently rocking the keg every now and again and releasing pressure using the relief valve, until the desired level is reached. Alternatively, allow the keg to come to room temperature and rock the keg/relieve the pressure over the course of a couple of days and then start your preferred method again once you have re-chilled your keg.