Not long ago I decided to move away from carboys and age my sour and brett beers in pin lock kegs. I’ll go more in depth on the reasons behind that in a future post, but the biggest hurdle to overcome with this move was to allow for adequate pressure relief during secondary fermentation. Buying many spunding valves wasn’t an attractive option for cost reasons. I decided to build one spunding valve that would allow multiple vessels to relieve pressure as needed. This is a setup I have dubbed the Gas Reducing Multivessel System, or GREMS. I know – clever, right?!

The main problem to solve in building this system was preventing one keg from pushing gas if refermentation kicked off harder in one than another. A little searching turned up inline check valves on AliExpress. These valves could, in theory, be used on their own on a line out of each keg as they require 2psi to open the outflow, but I wanted more control. As an aside, they could also be useful as an anti-suck back measure on blow-off tubes after primary fermentation!

Building the GREMS

First I gathered all my parts and tools and laid them out in front of me. I only had the picture of what I wanted in my head, so I needed to visualise everything together to really see how it’d work. Fortunately things looked good.

Yes there is an extra QD here. That was for something else, but I accidentally put it on the table.

I started by building out a basic spunding valve setup. This used a cheap metal tee, a male to male sitting, and the pressure relief valve itself. There’s no reason you can’t use a bigger manifold, I just had a small one already on hand.

Next I attached the gas manifold using the male to male fitting.

I followed the manifold by attaching the pressure gauge. I mostly added this now for stability while sitting on the work surface. It was a much bigger gauge than I realised when I ordered it, but the price was right.

Now it was time to add on the hose barbs and the check valves. I used a short section of hose to connect the check valves to the hose barbs. Be sure to check the arrow for the right direction of the valves!

Now you have a fully assembled GREMS! It’s quite an easy build, really, and very useful if you happen to have multiple kegs of mixed fermentation beer that might not be finished fermenting.

I rigged up a piece of copper wire to serve as a hanger for the GREMS so I could easily access it and hang it from my shelving.

GREMS Part List

Pressure gauge, 1/4″ – 0-30 psi or 0-60 psi would be fine

Metal tee, 1/4″ – really anything can be used, it won’t be contacting beer

Gas manifold – as many ports as you’ll need

1 male to male 1/4″ fitting

Adjustable Pressure Relief Valve

Enough hose barbs for your manifold

3ft of gas tubing for each hose assembly

1 gas ball or pin lock quick disconnect for each hose assembly

1 inline check valve for each hose assembly

4 hose clamps per hose assembly