Growler Tap



  The german growlers are a 2L swingtop with stainless steel straps and an aluminum handle.  The "growlers" most people are familiar with are actually half-gallon jugs.  The jugs have either a plastic or metal screw cap.  Jugs can NOT be used for carbonation or pressurization.  This is in contrast to the german growler shown at the left.  The german growlers are made to handle about 58 PSI (4 bar) an can be used for carbonation.  I've sucessfully tested mine with 20 PSI overnight. Most homebrew stores carry german growlers or they can be ordered from numberous websites.  You can find out more information about the german growlers from Anatomy of a growler.

Now that you know what type of container you can use, lets get started with the growler tap.  I borrowed this design from numberous websites that contain details on 2L Coke/pop bottle taps.  Another option to the german growler. So here are some of those links.

2L party keg

C.D. Pritchard 3L Pop bottle Mini-Kegs 

I constructed my tap (shown right) of items from Home Depot/Lowes and the local homebrew store. 

Parts List: 

  • 1/4" SS tube
  • 1/4" compression to 3/8" NPT
  • 3/8"  Tee 
  • 3/8" NPT tire valve (found mine at Ace Hardware)
  • (2) 1/2" SS washers
  • #10 stopper with a 1/2" hole, soft rubber (easily squezzed)
  • wing from a large black binder clip (borrowed from work)
  •  1/4" x 1-1/2" nipple
  • 1/4" Pipe coupling
  • Tire gauge for measuring pressure
  • 12g CO2 cartridge
  • Genuine Innovations Ultraflate Plus (CO2 tire inflater), this one screws onto the valve shown below (bike shops should have this)







Each external tread is wrapped in teflon tap.  The compression fitting is drilled out so the tube can pass through.  Only drill out the externally threaded portion, NOT the actually compression.  After application of teflon tape, the tube is passed through the compression and 3/8" T.  Tighten down the compression at desired length and tighten into the "T".  Attach tire valve to "T".  Place a washer on top of the nipple, and screw nipple into "T".  Tighten nipple into "T" with pliers. Push stopper onto nipple. On the bottom portion of nipple place another washer and tighten with pipe coupling.  Tighen coupling a little more than finger tight.  Try not to compress the stopper to much, if the stopper starts to buldge you have tightened to much.  Test tapping device on growler.  The stopper will protrude from the growler about 1/4" or so. To secure the tapping device to the growler I used a highly customized in-house devloped retaining ring. The retainer ring is used to hold the device securely to the growler. The design of the retainer ring is what plaged me for a long time and then it hit me one day. The retainer ring is shown below. 

The retainer ring is made from a large binder clip.  The clip is bent so the "head" is facing upward with knees is the center and the legs facing upward and out.  The legs stradle the top of the tapping device up to the knees and the legs are secured into the swingtop portion of the growler.  Securing the legs into the swingtop will requrie a little pressure on the legs.  Place the legs just bellow the porclein "hinge".  To secure the head use the latch of the growler. Although it may not seem secure, it is. I tested mine (no liquid) with 20 PSI and it was able to hold 20 PSI overnight and did not lose any pressure.  I had to "mess" with the retainer ring a little bit to get it to fit properly and in a confident manner, but it works. 

Dispensing beer 

To dispense beer, open tap full and start applying pressure till glass is full.  I have not tested with beer yet only water, but will update if needed.

Carbonating or storing beer

When you are done drinking for the night apply about 10 PSI to growler and place in fridge. 

Getting a feel for using the tire inflater will requrie a little practice.  It's like a car clutch.  You don't need to push the clutch all the way down to get it to work, only to the point of activation.  That is how you will work the tire inflater.  Pull it back only to the point of activation, NOT all the way.  

Notes and questions

Two questions/complaints people have are CO2 cartridges have oil in it for lubrication and the cost of the CO2 catridges.  Yes CO2 catridges used to have oil in them (1950/60's but they do not now). This is based on what I've read.  If you are uncomfortable with the idea of oil in a CO2 catridge, you should not be looking at pressurizing a glass container either.  I would consider pressurizing a glass container a bigger problem.  The second problem some people have are the cost of the CO2 cartridges and despensing of a small volume of beer.  Yes its true that the CO2 catridges are a "little pricey" (~$3 for 5 at Walmart), but its worth it for carbonated beer, I think.  The ability to carbonate beer and keeping beer carbonated is why I started this project.  This project could easily be modified for force carbonation of beer.  Instead of the compression fitting place the tire valve at the top and a pressure gauge on the side to carbonate.  The other option is to just use a straight connection going to the tire valve and carbonate with the tire inflater.  Of course there are many options to this, but I will let you work out your own method.  Good luck.

Let me know if you have any questions or comments.

jfenton78 at gmail dot com