I finally got my “Corny Keg” system working. And in spite of the rather large amount of pipework, it does give a lovely result.
The picture shows the keg itself on the left and the CO2 cylinder on the right. There’s enough pipe to be able to put the gas cylinder in a cupboard, and just have the keg out on the floor. Right now I’ve got a simple dispense tap attached directly to the keg, but it’s also possible to have a beer line to a dispense point, rather like a pub counter mounting.
The problem that I had was that the Gas Out line from the regulator needed a pipe with an internal diameter of 8mm but the Gas In adapter on the keg need a pipe with an internal diameter of 6mm. The pipe that came with the regulator was supposed to be a compromise for both ends. It was imperial rather than metric (17/64″ internal) which equated to 6.7mm. That made it a very loose fit at the keg end, and completely impossible at the regulator end. When I heated it up, it melted before it expanded enough to go onto the barbed fitting. How frustrating!
The good folks at Pegasus Industrial Services came to the rescue, via their eBay shop where they’re happy to sell small quantities of pneumatic pipe.
After some experimentation, the simplest way to do it was with a short length of nylon pipe with a 10mm outside diameter and 8mm inside, stepped down via a single pneumatic connector to a flexible polyurethane pipe with an 8mm outside diameter and 5.5mm inside. Both needed heating, but only in boiling water, to gave a good tight shrink fit. As a precaution, I put a jubilee clip on the regulator end as well.
The remainder of my first Grainfather brew went nicely into one keg. I’m beginning to feel a bit sorry for the way that batch has been handled, what with leaky fermenter problems necessitating a complete decant and now being poured from barrel to keg. I’ve kept everything sterilised, of course, but it’s all far from best practice.
Still highly drinkable, though:
Yes, you’re right. That is a bit frothy. I misread the gauge, and instead of setting the dispense pressure at around 2psi, I set it at first to 2 bar (nearly 30psi). It’s settling down nicely, though.
John Norman's Blog 
Ooh, another thing to explore, thank you. We’re at last drinking the results of our first Grainfather brew, and it’s surprisingly good. [I have no idea what it is, which is why I haven’t replied to your question on my blog. I will remember to ask and let you know] Very pleased with the beer.
I’ve no idea whether a Corny Keg is of use to us, but I’ve forwarded the info on to DH to see what he thinks. I know we’ve put beer in a keg before and used the old-style soda stream cylinders on it.
Thank you for sharing
The results from the Corny Keg system are so good that the initial pain of the investment is beginning to fade! A bit, anyway. Right now you can get discounted second-hand kegs from here: https://www.thehomebrewcompany.ie/a-used-corny-keg-19lt-ball-lock-p-2870.html
Even at the pre-discount price (which is when I bought mine), they were a bargain. You’ll need two of that size to accommodate a typical Grainfather brew. I bought three, on the grounds that as we were finishing one batch, we could be filling up the other two with a fresh lot.
You’ll need to budget for a good quality regulator and the deposit on a larger CO2 cylinder as well, plus the bits and pieces for connection, including a dispensing tap. You’ll need to find a local CO2 supplier for “cellar gas”.
The beer still looks great!
Hello John, we’re really enjoying using the Grainfather. Today we had a flyer for a potentially interesting product , haven’t had a chance to look into it yet – wondered if you had seen or considered it? It’s called the FastFerment.
Hello Hazel,
Yes, I also bought a FastFerment. I’ve actually commented on it in one of the blog entries. The design is excellent – the bulb at the bottom really does collect the yeast for re-use, and the trub thereafter.
The problem is in the execution. It’s made of relatively soft plastic, although the screw-on joints are of a harder material. They provide you with a reel of plumbers tape, which should have rung alarm bells with me. In spite of following the instructions carefully, the blooming thing leaked like a sieve on its first outing.
I switched to gas tape (easily available from Screwfix and similar outlets), which solved the problem. But even now the top isn’t airtight, so the CO2 simply leaks out of the lid and doesn’t bubble through the airlock.
I still love the design, and I’ll continue to use it, but it’s by no means perfect.
John
PS, since my original comment back in August we’ve now got 3 corny kegs on the go
They’re great, aren’t they? Three is the ideal number for serial home brewing, I agree.