How to Keg Beer Part 2: Cleaning and Prepping

If you’re planning on kegging your homebrew rather than bottling it, you may be a little confused as to how it all works. Fortunately, our 5 part guide takes you through every step, teaching you how to keg beer easily and efficiently. It’s really not as difficult as it seems, and once you get going you won’t look back!

In part one, we took a look at the equipment you will need to get started. In this second part, we’ll take a quick look at cleaning and prepping your keg ready for filling. Perhaps you can guess how to clean a keg, but there a few tips and tricks well worth knowing if you want to remove any danger or spoiling your first batches!

How to Clean a Keg

Before filling a keg, it’s essential that it has been properly cleaned and sanitised. As is the case with bottles, this ensures the beer stays fresh longer, and prevents spoilage, the difference is it’s much quicker and easier to clean 1 keg compared to 40 bottles!

Taking Your Keg Apart

Even if your keg is brand-new, it’s a good idea to strip it down and give it a good clean before first use. First and foremost, ensure the keg is depressurised — most kegs have a pressure release valve, normally a ring you can pull on the lid. If yours doesn’t, you can attach a tap to the gas post (marked ‘in’) and leave it open until the pressure is fully released.

Use a 22 mm socket wrench or spanner to remove the gas and beer posts, pull out the dip tube, and remove the lid and gasket. If it helps, take a photo before disassembling your keg, to be sure you remember how to reassemble it later.

Soak & Scrub

With kegs you’ve just emptied of beer, it’s best practice to give them a good rinse first. This is best done in the shower, preferably with a high pressure shower head to dislodge any yeast or hops. Next half fill the keg with a mix of water and PBW (powdered brewery wash), around 11 litres of water to 65 grams for a corny keg. Add all the keg parts to the mix and let it sit overnight.

After soaking, use a non-abrasive brush or sponge to clean the inside edges of the keg, as well as all the components. A small pipe cleaning brush is great for scrubbing out the dip tube, which could have hop or yeast particles stuck inside. Finally, give everything a good rinse.

Reassemble, Soak and Sanitise

Once rinsed, reassemble the keg and check each component for damage — replace gaskets and o-ring as required. Add another solution of water and PBW, fit the lid, seal and turn the keg upside down. Leave it for an hour or so to clean the top. Then, empty it and rinse well with plenty of warm water.

Finally, add a sanitiser solution (preferably no rinse) to the keg. Close the lid and let it sit for 10 minutes or so. Give it a shake, flip it over and let it sit on the lid for another 10 minutes. Then, hook up your beer line (if filling a keg up shortly, use the hose you will use to fill), and use co2 to push out the sanitiser. Leave the keg pressurised and ready to fill.

Prepping Your Keg for Filling

With a nice clean keg, you’re almost ready to fill ‘er up. Before you do however, there are just a couple more steps. In order to more or less eliminate the risk of oxidation, it’s best practice to start by pressurising your keg with co2 and purging it of oxygen.

How to Purge Your Keg

This is done by fitting the grey gas disconnect to the in/gas post. Hook up your gas bottle and regulator, and release a small amount of co2 into the keg. Shut off the gas, then, using the pressure release valve — or a tap — release the oxygen in short bursts. As co2 is denser than air, it will sink to the bottom of the keg, pushing the oxygen to the top. Add more co2, and repeat 2 or 3 times to ensure the keg is filled with co2.

How to Pressure Test Your Keg

With your keg pressurised, you can now test it for leaks. It’s much better to do this now rather than wait until the keg is full of beer before discovering a leak. You’ll hear gas escaping from larger leaks — often if the lid isn’t fitted properly. For smaller leaks, the easiest way to detect them is to spray a no rinse sanitiser solution onto the gas and beer posts, and lid. If gas is escaping, bubbles will rapidly form in the area.

If you find a leak, try tightening the component in question, or in the case of the lid, simply re-fit. Release any gas before attempting to remove any component — otherwise parts can fly off and may even be fatal. If tightening or refitting doesn’t work, 9 times out of 10, you’ll need to replace an o-ring or gasket — so, be sure to stock up on spares!

As with most elements of brewing, cleaning and sanitising is vital during kegging. A clean, sanitised keg will prevent spoilage of your beer and will keep it fresh far longer. Now that your keg is ready to go, it’s time to fill it up with homebrew. Check out part 3 of our essential guide to kegging for a step by step guide, plus tips and tricks.