Counter-Pressure Filling Techniques

So then you moved on and tucked all your bottles away in the garage and got a kegging system. Kegging does have its limitations though, especially with transportation and storage. In most cases, it’s easier to bring beer to a friend’s house in a bottle or growler. If you are competing in a homebrew competition, most times you will need to provide your beer in a bottle.

The easiest way to bottle once you’re kegging is counter-pressure filling. One of the most appealing benefits of counter-pressure filling for many people is the ability to bottle without sediment. Bottling, already one of the more tedious or annoying steps in the homebrewing process, leaves noticeable amounts of sediment in bottles. This is one of the top complaints from new homebrewers looking for a commercially comparable product. As a homebrewer, controlling the amount of sediment and getting proper natural carbonation can be tricky. By force carbonating in a keg, the CO2 is added directly to the beer instead of being created by the yeast, which grows a colony before dying in the bottom of your bottle, creating this sediment.

Luckily, bottling beer off of a keg is a quick and easy way to sediment-free carbonation in the bottle. Let’s take a closer look at counter-pressure filling.

PREP WORK

The first step in counter-pressure filling, as with most things in homebrewing, is to make sure that your counter-pressure filler, bottles, and other equipment are cleaned and sanitized. Most counter-pressure fillers can be completely sanitized by being submerged in a bucket and opening any valves. You will be using liquid tubing from your keg as well as the bottles you’ll be filling, and these can also be submerged in the sanitizing solution.

Keep in mind that if you weren’t diligent when cleaning your counter-pressure filler after its last use, there are a lot of areas the beer touches you can’t see. Try running cleaner solution through all of your tubing and the counter-pressure filler. Filling a keg with cleaner and attaching the counter-pressure filler as you would to fill bottles, pushing the solution through with CO2, is a good way to ensure the inside is well cleansed.

Also, be sure that your beer is already properly carbonated. You should be able to pull a pint off and enjoy prior to filling any bottles. The CO2in the beer is the only carbonation you’ll have, don’t expect miracles in the bottle if your beer is going in under-carbonated.

You will also want to chill the beer as well. This will cut down on foaming that may occur during the filling process, as CO2 stays in solution better at colder temperatures. The general rule is as cold as possible, down to 32 °F

(0 °C). This is because beer has alcohol, which means the freezing point becomes lower than water. Chilling the bottles you plan to fill prior to actually filling them with beer will also cut down on foaming. It will also ensure the beer stays cooler during transfer, and thus releasing less CO2.

COUNTER-PRESSURE FILLER VS. BOTTLE FILLER

This article could probably be more aptly named “Post Carbonation Bottle Filling” as I’ll be discussing two types of bottle fillers. “Counter-pressure” has been the term coined for post-carbonation filling for some time by homebrewers, although techniques have changed and “counter-pressure” isn’t always used during the fill.

There are numerous different counter-pressure filler devices out there, but there are also bottle fillers that don’t use “counter-pressure,” or some sort of stopper to close the bottle while purging with CO2 and filling. Bottle fillers, often called beer guns, simply purge the bottle with CO2 prior to filling, and are meant to fill from a keg just like a counter-pressure filler. In almost all aspects they are used in the same way. Beer guns that don’t use counter-pressure include the Blichmann BeerGun™ and Northern Brewer/Midwest Supplies The Last Straw™.

Both counter-pressure fillers and beer guns should fill the bottle from the bottom, as well as purge from the bottom. This ensures less foaming, that oxygen is pushed out, and that as little oxygen is introduced as possible during the fill. Oxygen is the natural enemy of post-fermentation beer and a counter-pressure filler is designed to minimize its uptake. Despite best efforts, a small amount will most likely make its way into your bottle.

Does your bottle filler need to be considered a counter-pressure filler in the traditional sense to bottle beer from a keg properly? The short answer I’ve found is no. After some simple tests, and with the help of some professional lab equipment, I can recommend most counter-pressure fillers and beer guns out there. Putting the bottle under pressure with a stopper closing the top and allowing pressure to build in the bottle is not necessary, but it is insurance. I tested this so you wouldn’t have to run out and buy expensive equipment just to see for yourself.

I used WilliamsWarn’s counter-pressure filler and matched it against a Blichmann BeerGun™ bottle filler. I had both available, and the design of both made each easy to use when filling. The BeerGun™ did foam more than the counter-pressure filler, though I was able to improve this by slowing the dispensing down some from the keg. Foam over is something to keep in mind when you choose where you set up to fill bottles.

After bottles were filled from the same keg, at the same temperature, using the manufacturer’s recommended filling method for each device, both provided the same amount of pressure in the bottle. The Zahm & Nagel Piercing Device, a professional device used in breweries to check CO2 in bottles and cans, confirmed this for me. Counter-pressure filler or beer gun style? Both work well.

CARBONATED BEER – BOTTLE FILLING STEP BY STEP

Bottle filling from a keg can seem expensive if you consider the cost of a kegging system, and it is, if you’re purchasing it just for bottle filling. For many, a kegging system has already been purchased, and the decision to bottle off their keg comes down the road. The one additional piece of equipment beyond your keg, CO2 tank, tubing, and keg connectors is a CO2 regulator with wye splitter, or a two-way gas-out from your regulator. You’ll be keeping the keg connected to gas for dispensing, as well as your bottle filler at the same time. A two-way gas splitter at the regulator is common, but a simple barbed tee splitter in your line will work as well. If you have a two-bodied regulator, or two CO2 canisters with regulators, then you have two gas outputs and can purge and fill appropriately.

STEP ONE: THE PURGE

Whenever dealing with glass and potentially high pressures, safety glasses or a face shield are required. This is a must when applying pressure to bottles!

Set your gas regulator to somewhere around 10 psi. This is an average conditioned pressure for most beer. If you find you need the beer a bit slower, or faster, adjust accordingly. Each device and beer will have a sweet spot. Running too fast can create turbulence and excess foam, running too slow can have a similar effect as CO2 releases from solution in the lower pressure bottle from the higher pressure keg.

Once connected to your counter-pressure filler, open your gas valve to begin purging. You will have a bleed valve to relieve pressure in the bottle as you purge and then fill. Beer guns will not have this valve. After a couple seconds crack open your bleed valve until you hear it hissing. Typically, counter-pressure fillers and beer guns recommend 5–10 seconds of purging. I think 5 should generally suffice, though for those more cautious or concerned about oxygen, go longer. There’s no way to easily measure the CO2 going in the bottle, so a bit of guesswork is required here. Finish purging by closing your bleed valve, than your gas valve.

STEP TWO: FILLING

Your stem should be near the bottom of your bottle to minimize oxygen introduction. CO2 is slightly heavier than air, which is mainly composed of nitrogen, N2. The stem should be in your pool of CO2 at the bottom of the bottle while oxygen is forced upward towards the neck of your bottle.

Open your liquid valve. If you’re using a beer gun, the beer is flowing. If you’re using a counter-pressure filler the “counter-pressure” from the keg and the bottle are equal, and beer will not flow. By opening your bleed valve you relieve this pressure, allowing the beer to displace to the lower pressure in the bottle. And that’s how counter-pressure filling got its name!

How far you open your bleed valve with determine your flow rate to the bottle. Most fillers take 10–20 seconds. Some newer fillers have a pressure gauge on the relief valve. Try and relieve between 2–4 psi and see what works best for you.

If for any reason things don’t seem to be going well, turn off your CO2 from the tank, close your filler’s valves, and open your bleed valve to relieve any built up pressure in the bottle. Remove the bottle, and begin the steps again. It takes some getting used to the process, but once you’ve got the mechanics down, you’ll feel like a well oiled machine turning out perfectly carbonated beer with minimal loss of beer or time.

For most beer guns, this process simply involves pressing a trigger for beer, and releasing when finished filling. You are not filling against any pressure in the bottle.

STEP THREE: CAPPING

Any foam left in the neck only improves your chances of having minimal oxygen in the bottle when you cap, and is considered a necessary part of this type of bottle filling. Until now, we’ve been talking about how to minimize foam, as too much will make a sticky mess (and a significant amount of lost beer), but not enough may allow for aeration. I typically allow a bit of foam to come out through the bleed valve at the end of the fill, or just to crest the lip of the bottle when filling with a beer gun. Close your liquid valve and then your bleed valve, the opposite will create pressure, and remove the bottle. Your fill can go to near the top of the bottle, a small amount of displacement will happen from the removal of the filler stem.

If you have ample foam coming up through the top of your bottle, cap immediately. If you’re finding you don’t have much foam, or you want to be sure there’s minimal oxygen, use the “cap on foam” tap. By tapping on your beer bottle you release CO2 into the headspace. I was shown this method with a screwdriver. Gently tap the side of the bottle once, and be ready to cap immediately as the volcano of foam erupts through the neck. Be careful, you’re tapping glass! It’s better to have too soft a touch and need to try again than to have beer and sharp glass everywhere.

STEP FOUR: CHILL AND SERVE

As with any beer, keep your bottles chilled. Don’t worry if you don’t hear the classic ‘pfft’ sound upon opening. CO2 takes time to fill the headspace in a bottle, and without the pressure against the cap, you may think your beer is flat. Give it a try, and if you followed all the steps, you’re enjoying sediment-free, perfectly carbonated beer from a bottle!