by Jane Jackson
These five simple steps will ensure that you are filling your growlers without loss of carbonation or aroma.
Learn. Fill. Share. Repeat.
At least one day ahead, make sure that your keg and growler are cold and that the keg is fully carbonated.
Warm beer doesn’t hold CO2 in solution which means flat beer. Also, make sure that you put your growlers in the fridge the night before. Transferring cold, carbonated beer into a warm container will speed up the loss of CO2 out of the beer.
Which type of growler is best for your needs?
Consider size and closure type before deciding on a growler. Once you break the initial seal after filling your growler the beer is moving closer to becoming flat. If you plan to share a bunch of beer with a lot of people all at once, a larger container like a 2 Liter Glass Palla Style Flip Top or an insulated stainless steel DrinkTanks® Growler is a great choice.
2 Liter Palla Style Flip Top Growler
The super secure flip top lid with gasket creates a great seal and holds pressure better than most screw cap containers. If you are using a screw cap growler, be sure to choose a polyseal cap, not a metal cap, for the much better seal it provides.
Polyseal Cap provides a better seal than other types of screw cap
Insulated growlers such as the DrinkTanks® Growler help keep the beer colder even out of refrigeration or a cooler, keeping the CO2 in solution in the beer. If the growler is for personal consumption or you plan to make it last over the course of several hours, one or more smaller sized growlers are a better choice. A 32 oz screw cap growler, 32 oz insulated DrinkTanks® screw cap growler, or a 1 liter glass flip top bottle are enough for two personal pints or sharing. Again, once you open the growler the beer is going to start losing carbonation. A few smaller growlers will remain better carbonated even after opening than will a large growler with increasing head space.
32 oz screw cap growler
32 oz insulated DrinkTanks® screw cap growler
1 liter glass flip top bottle
Depressurize your keg and adjust regulator psi to 2-5.
It seems counterintuitive to release the pressure and turn down the psi when you are trying to maintain full carbonation. But if the beer in the keg is cold and has been fully carbonated, the CO2 will stay in solution during the growler filling process. Depressurizing the keg and lowering the psi to a pressure just enough to push the beer from the keg to the faucet leads to a smooth, although slower, fill. Trying to fill a growler at the same psi you usually serve the beer at creates a fast, furious, and foamy rocket of beer. The rougher transfer from keg to growler drives the CO2 out of solution in the beer, accelerating the path to flat beer before you have even been able to taste and share it. Filling at serving psi leads to a lot of foam, meaning you have to fill the growler over a longer period of time so you can replace all that foam with beer, also resulting in a loss of CO2 from the beer.
Attach a growler filler to the faucet.
The best way to keep the foaming down and the CO2 in solution is to fill from the bottom up. Most often this is attempted with a floppy piece of tubing over the faucet itself or on a growler filler attachment inserted into the faucet.
The tubing-over-the-faucet method is better than straight from the faucet to the growler, but still not a great practice. A much wider diameter of tubing is needed to fit over the faucet spout and this takes up a lot of space in the growler making it harder to get a good, tip-top fill. Tubing on the growler filler attachment is a bit better, but often the tubing is curly, floppy, and unwieldy, making it hard to get a good, bottom-up fill. The Beverage People’s Growler Filling Set with Rigid Tube is available for both a standard faucet growler filler and the Intertap growler filler, making it easy to get the tube straight to the bottom of the growler for a more gentle fill. Simple, affordable, and effective!
Growler Filling Sets with Rigid Tube - Available for Standard and Intertap Faucets
If you really want to have the most gentle, least oxygenating growler fill, you can use a counter pressure bottle filler, such as The Beverage People’s CPNO2™. Using your already cold, carbonated keg and your CO2 tank you will use gravity and balanced pressure to fill from keg to growler with little to no loss of CO2 in the transfer and fill. However, this approach requires a bit more effort and equipment, which may not be worth it for the occasional one or two growler fills.
CPNO2™ Counter Pressure Bottle Filler
Purge growler with CO2.
Oxygen is not a friend of carbonated beer. Oxygen exposure leads to stale beer, including the loss of aroma. This can easily happen during the growler filling process. Displacing the oxygen with CO2 immediately before growler filling helps eliminate this possibility. A couple of options for purging are our handheld CO2 mini purger, which takes threaded 16 g. CO2 cartridges, or our gas purge wand with button valve which, when adapted with a ball lock gas keg post, can hook up to your regular CO2 tank’s ball lock gas fitting. A few seconds of purging with CO2 and you are ready to fill with beer.
Mini Purger can flush oxygen out the growler
Purge Wand can be connected to any gas system
Fill and cap on beer.
If you don’t have a drip tray, it can be helpful to place a bucket or bowl on the ground under the faucet you will be filling from to collect any overflow. Slide your cold, CO2-purged growler over the filler tube and open the faucet tap. The filler tube should reach the bottom of the growler. As the beer flows into the growler, make sure that there isn’t any splashing or gurgling. If the flow is too slow (it should be relatively slow) or there seems to be air bubbles in the line you may need to adjust the psi up a bit. If the flow is too fast and you are experiencing a lot of agitation or foaming you may need to adjust the psi down a bit. Continue filling the growler until beer, not foam, overflows the growler. Quickly seal the cap. We call this “capping on beer”. You don’t want to allow any space in the growler for the beer to lose carbonation. A little spilled beer at home is worth it to have cold, carbonated beer to share later. Cheers!
Step 1: At least one day ahead, make sure that your keg and growler are cold and that the keg is fully carbonated.
Step 2: Depressurize your keg and adjust regulator psi to 2-5.
Step 3: Attach a growler filler to the faucet.
Step 4: Purge growler with CO2.
Step 5: Fill and cap on beer.
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