Marty's Counter-Pressure Bottle Filler

Marty Tippin (

Original: November 2, 1996
Last Update: August 21, 1998

August 21 1998: Since my interests have shifted away from homebrewing, I've sold all my equipment and am essentially out of the hobby for now - but these pages will remain online for the foreseeable future. And I'll still be around to answer questions, so don't hesitate to e-mail me!



Inevitably, most people who use 5 gallon soda kegs to dispense homebrew find themselves wishing they could fill a few bottles with the kegged beer now and then - maybe for a homebrew competition or to take along on a camping trip or over to a friend's house for dinner.

So you go grab a few bottles and decide that you'll just fill them up from the picnic tapper. And it turns out to be a disaster. The problem with trying to fill a bottle directly from the tapper is that the beer foams and fobs and generally goes flat before you can get the bottle capped (if there's still any beer left in the bottle by the time you can get the cap on.)

The reason the beer foams and fobs is because of the sudden change in pressure - it went from being under 10 to 20 psi in the keg to 0 psi in the bottle, which causes the dissolved carbon dioxide to rapidly come out of solution. The way to avoid this problem, then, is to keep the bottle at nearly the same pressure as the keg until it is full, and then to quickly cap it before the beer figures out there's been a drop in the surrounding pressure. That's the basic principle behind a counter-pressure bottle filler.

Table of Contents

Simple Methods
High-Tech Methods
Parts List
Copyright, Disclaimer and Other Nonsense

Simple Methods

As a small step up from the no-technology method of filling straight from the tapper, you will find that a simple and functional filler can be made by sticking a piece of 3/8" outside diameter (OD) rigid tubing into the head of your tapper (this assumes you use the picnic or "cobra" style tapper - a black plastic gizmo that you squeeze to let the beer out), then attaching to the tubing a drilled rubber stopper of the size to fit in a beer bottle. You jam the whole thing down onto your bottle to seal it and open the tapper. After a few seconds, the pressure in the bottle equalizes and beer stops flowing. So you raise the stopper slightly to "burp" a little air out and more beer flows. This process continues until the bottle is full, at which time you quickly cap the bottle. The most obvious advantage to this method is that it's cheap - if you've already got a plastic bottle filling wand with a removable tip, all you need to add is a drilled stopper and you're all set - total cost: less than $5. However, this method is less than optimal because there will inevitably be some foaming and you don't have a way to purge the bottle of oxygen before you start filling - if there's any oxygen left in the bottle when you cap it, the beer will get oxidized and go stale much quicker than it would if there were only CO2 in the headspace.

Ken Schwartz has come up with a nifty enhancement to this simple method - you can check out his Poor Man's Real Counter-Pressure Bottle Filler if you're interested. I looked at the design and contemplated building one, but I'm far too much of a gadget freak for something that simple.

High-Tech Methods

There are several commercially-available counter-pressure fillers, usually selling for around $50 in most homebrew shops, not including the tubing or fittings to connect it to your keg and CO2 cylinder. The Fall 1995 issue of Zymurgy had a review of several commercial fillers; if you're thinking of buying one already made, check out that article first. The cost to build the filler I'll be describing shortly is comparable to the commercially available filler; you may be able to build it cheaper if you already have some parts on-hand or look around to find the cheapest stuff.

I recently ran across another innovative design by C.D. Pritchard and was quite impressed by the simplicity of the design, but I lacked the machining tools (like a drill press) required to do a good job in constructing it, so the search went on. If you have access to a drill press, you can probably save quite a bit of money by building C.D.'s counter-pressure filler.

Just a few days ago, I found a web page by Dion Hollenbeck containing his collected brewing knowledge. Among the many good items on his page was an article describing how the counter-pressure filler sold by Foxx Equipment Co. was made. Their filler is made from readily-available fittings and was therefore suitable for my next gadgeteering project, so I ran down to the local hardware store and bought all the pieces I needed and went to work.

Dion's article was pretty basic (no offense, Dion!) - just straight text describing little more than the basic construction of the filler. But it was enough that I could figure out how to build the thing. I decided after building mine that I would put together this web page and throw in a picture or two to hopefully make construction and use of the filler a little simpler for others who might like to build one.

Parts List

Note: "NPT" stands for National Pipe Thread and is a standard thread for pipe fittings. You may also see it abbreviated as MPT or MIP (for Male threads), and FPT or FIP (for Female threads). All parts (except the quick disconnects and stainless steel tubing) were obtained at the local Ace hardware store; similar parts should be avilable at most any hardware store.

* The Stainless Steel tubing may be hard to find in your area. There is a local company that deals exclusively in stainless tubing and pipe fittings, and I was able to obtain a scrap piece of 1/4" OD tubing for $5. If you can't find stainless steel tubing locally, you may be able to use 1/4" OD brass or soft copper tubing. Though extremely inexpensive, neither of these is ideal - they bend much too easily. One other alternative would be to contact Small Parts, Inc. at 800-220-4242. As the name implies, this company deals in small, hard-to-find parts. Their catalog shows a 24" length of 1/4" OD tubing (part no. E-GPTX-35/4-24) for $8.07 plus shipping. There may be other, cheaper mail order sources - look around and you may get lucky. In fact, Stainless In Seattle may carry tubing in this size; I haven't checked for sure but it may be worth your time..


All parts should be thoroughly cleaned and rinsed before assembly to remove grease and other nasty gunk; I used a strong TSP solution (TSP is an industrial-strength cleaner, available in the paint section of any hardware store) and hot water. If you're worried about the potential danger of lead on the surface of the brass parts, you can soak them in a solution of 2 parts white vinegar to 1 part hydrogen peroxide for 15 minutes at room temperature to remove the surface lead - the brass will turn a buttery yellow color when it's done. (Thanks to John Palmer for this information.)

(Refer to the diagram of the completed filler if these instructions are unclear; between the picture and my attempt at using the English language, you should be able to figure it out. ;-)

Be sure to wrap the threads with about 3 turns of the teflon tape to make assembly easier and to seal against leaks!

Start with the brass tee at the top of the diagram. Attach the 1/4"MPTx1/4" Compression connector to the middle of the tee. On the ends of the tee, attach the 1/4"xClose nipples, and to the nipples attach the ball valves. Orient the ball valves so that the lever is pointing away from the tee in the "open" position. Finally, attach the nylon hose barbs to the ball valves.

Now get the other brass tee. One one end of the tee, attach a 1/4"NPT x 1/4" Compression connector, and the 1/4"NPT x 3/8" Compresion connector to the other end. As you can see in the photograph, this assembly is oriented so that the middle connector on the tee points to the right. Attach the right-angle needle valve to the middle of the tee. To the needle valve, attach a short length of 1/4" OD tubing. Orient the valve so the tubing points toward the 3/8" compression fitting.

The tee assembly must slide over the 1/4" OD stainless steel tubing, using the 1/4" Compression fitting to lock the assembly in place. I had to drill out the inside of the 1/4" Compression fitting with a 1/4" drill bit to allow the tubing to slide through. Attach the 1/4" stainless steel tubing to the 1/4" compression fitting on the first tee, being sure to slide a compression collar onto the tubing before tightening the nut securely. Attach the short length of 3/8" OD copper to the 3/8" Compression fitting on the other tee and tighten. Put the drilled stopper over the copper tubing with the wide end of the stopper closest to the tee. Slide the remaining 1/4" compression nut and collar onto the stainless tubing and then slide the second tee onto the tubing. Tighten the compression nut just enough to hold everything in place. (If you overtighten the compression nut, you'll crimp the compression collar and it'll be permanently stuck wherever it happens to be!)

Now find the shortest bottle you expect to fill. Place the end of the filler into the bottle so it is about 1/2" from the bottom of the bottle. Slide the tee down so the stopper is firmly planted in the bottle opening. Hold everything in place and finish tightening the compression nut. (During use, if you need to fill a taller bottle, you can add a short piece of 1/4" ID vinyl tubing to reach the bottom of the bottle. If you later find an even shorter bottle, you can use regular tubing cutters to whack off a little of the stainless steel tubing.)

The basic construction is now complete; the next step is to attach the tubing. Start with the nylon hose barb tee. On one end of it, attach a length of tubing with a Gas-In quick disconnect on the other end. The other end of the tee needs another length of tubing that goes to your CO2 regulator. I use a quick-disconnect fitting on my tank so I can interchange various gadgets quickly and easily. You can use the regular type of quick-disconnect intended for compressed air, or you can order a special fitting designed expressly for CO2 - I ordered mine from a company called "Rapids" at (800) 472-7431. Finally, the middle of the tee needs to be connected to one of the nylon hose barbs on the filler (either one is fine) via yet another length of tubing. The only connection left to make is to attach a length of tubing to the remaining nylon hose barb and add a Liquid-Out quick disconnect.

I recently conversed with Dion Hollenbeck and he had a very interesting (and useful!) suggestion regarding hooking up the tubing:

"I, personally, NEVER connect beer line or CO2 line tubing to hose barbs with pipe threads. This permanently connects the hose to the device and not only requires many more hoses, but also has hose flopping from every device around. I use hose barb to 1/4" female flare fittings on all hoses. These screw directly onto all my keg Quick Disconnect fittings (I do not buy QD fittings with hose barbs either, for the same reason). All my equipment is equipped with 1/4" male flare fittings so the hoses just screw right on. Hoses can be hung up on a hook to drain dry after use and equipment can be put away without hoses. You only have to have as many hoses as you will ever use simultaneously, not two for every piece of equipment."

Dion's suggestion is worthwhile and I'm planning to retrofit all my gadgets with the flare fittings he describes. Should make things a lot easier all the way around.


The first step is to sanitize the filler before use. I keep a keg full of an Iodophor solution on hand at all times for sanitizing hoses, bottles and anything else that needs it. If you've got a spare keg, I highly recommend it. So what I do is attach the filler to the Iodophor keg (Liquid-Out and Gas-In) as well as the CO2 cylinder (make sure both ball valves on the filler are closed before you attach anything!) Pressurize the keg to around 10 psi and put the business end of the filler in a spare bottle, firmly seating the stopper into the bottle. Crack open the liquid in ball valve and the pressure relief needle valve and allow the bottle to fill with sanitizer until it overflows. Close the ball valve and the pressure relief valve and let the whole thing sit for a few minutes. With the filler still stuck in the bottle, disconnect the Gas-In quick disconnect from the keg and open the gas-in ball valve on the filler. Open the liquid-in ball valve on the filler also. Now if you use the pressure relief valve on the keg to bleed off a little of the keg pressure, you can force the sanitizer in the tubing to flow back into the keg. Once the tubing is empty, close the liquid ball valve and the gas ball valve. Remove the filler from the bottle and crack open the gas ball valve to purge the remaining sanitizer from the filler. If you don't

You're now ready to go. Round up as many sanitized bottles and bottle caps as you want to fill and get the bottle capper adjusted and nearby. Your kegged beer should be fully carbonated and chilled as close to 32F as you can get it - that helps minimize foaming. The keg and CO2 regulator should also be pressurized the same (around 10 psi works for me.) You'll also need a tray of some sort to catch spillage.

Make sure all three valves on the filler are closed before you attach anything! Connect the liquid-out quick disconnect to the keg, then connect the CO2 cylinder to the filler and finally connect the gas-in quick disconnect to the keg.

The basic sequence for bottling is as follows. The first few times are akward and you're probably going to open the wrong valve at least once and get a face full of beer. (Common sense would dictate that you use some sort of eye protection while using the filler- both to protect against spraying beer and the remote chance of an exploding bottle. I don't know anyone who's had this happen, but it's always possible when working with compressed gasses.)

  1. Insert the filler into a sanitized bottle and firmly seat the stopper in the neck of the bottle.
  2. Open the gas-in ball valve fully and allow the bottle to reach the same pressure as the keg.
  3. Open the pressure bleed valve slightly to allow the oxygen in the bottle to be purged and replaced with CO2. Leave it open for 10 seconds or so.
  4. Close the pressure relief needle valve and allow the bottle to pressurize again.
  5. Close the gas-in ball valve.
  6. Open the liquid-in ball valve fully. No beer should flow into the bottle since the bottle and keg are at the same pressure.
  7. Open the pressure relief valve slightly. Beer should start to flow into the bottle. Don't get in too much of a hurry or you'll wind up with a foaming mess.
  8. Allow the bottle to fill until the beer reaches the bottom of the stopper. You need the bottles to be quite full at this point so you wind up with a decent headspace after the filler is removed.
  9. Close the pressure relief valve.
  10. Close the liquid-in ball valve. All valves on the filler are closed at this point.
  11. Crack open relief valve and allow pressure to vent slowly (make sure the process takes at least 15 seconds.) Some foam will be generated.
  12. Cap the bottle.

Copyright, disclaimer, and other nonsense

This document is copyright 1996 by Marty Tippin ( However, you may freely copy and distribute it for any non-commercial purpose, provided this copyright notice remains intact. I didn't pay anything for the information I used to design my filler and you shouldn't have to either - if this document is helpful to you, then feel free to use or modify any ideas contained in it! Anyone wishing to publish this information or otherwise use it commercially (whether in part or in whole) should contact me for permission first.

This device could be dangerous if used improperly. Always wear eye protection and work in a well-ventilated area. And if you do get hurt, don't come crying to me; it's not my fault... ;-)

Finally, if there's anything blatantly wrong or otherwise in need of correction in this document, or if you've got suggestions, questions or just need to unload on someone, please let me know - there's a link to my e-mail address at the top of this document.

Comments, questions, and suggestions for improvement are welcome! Send them to the author (e-mail address at the top of this page)