As promised, The Spunding Valve explored:
To Spund is the German term for To Bung, To Close Up or To Seal, not some trendy photo pose that’s the next best thing since Planking. A Spunding Valve is a device that has a Pressure Gauge to show vessel Pressure and a Release Valve to vent excess Pressure from that vessel.
- Spunding, in the brewing sense, refers to the act of closing off a vessel containing beer or wort and allowing Pressure to build inside the liquid. - By WortMonger in HomebrewTalk.com
While WortMonger’s definition makes a Spunding Valve sound suspiciously like something involved a case of blue balls, not to worry, it’s actually a good thing.
- It can be a useful way to naturally carbonate a beer.
- It can also be used to help transfer carbonated beer from keg to keg without losing any carbonation.
- In my case, I used one to vent the Pressure that would build up as I transferred the twenty13 EisGersteWein into a 3-gallon corny keg.
Spunding Valves can also be used to regulate the transfer of beer from one keg to another while under Pressure. While that is a great convenience for my EisGersteWein, it is downright necessary if transferring carbonated beer from one keg to another.
I didn’t want any chance of oxygen coming in contact with my EisGersteWein, so after purging the recipient keg of oxygen with CO2(@10 psi – twice), I wanted to keep its lid sealed. Instead of manually releasing the Pressure in the recipient keg as it built up during the transfer, I decided to make my own Spunding Valve.
Here are the parts needed to build your own Spunding Valve.
WIKA 9767045 Industrial Pressure Gauge, Liquid/Refillable,
Copper Alloy Wetted Parts…$15.00
Control Devices CR Series Brass Pressure Relief Valve,
0-100 psi Adjustable Pressure Relief Valve…$9.95
The Pressure Gauge, Relief Valve and most of the brass fittings used ¼” npt thread. the other plumbing fittings (female flare swivel, male flare to male NPT adapter, and NPT tee) were bought at my local hardware store.
While some homebrew shops offer similar Spunding Valves, their Pressure Gauges only go up to 15 psi. I bought a slightly more expensive Pressure Gauge that had a stainless steel body, with a wider psi range and that was also liquid filled. These are sturdier and I plan to use it for future carbonation projects. You can probably buy a basic Pressure Gauge that will suffice for only $5.00 though. Total cost for my Spunding Valve was approx. $40.
To use a Spunding Valve in a keg-to-keg transfer, make sure the recipient kegs is pressurized at a slightly lower pressure than the originating keg so there’s no chance of having anything flow backwards through the transfer lines. Hook up your CO2 tank to the originating keg and purge the transfer line so it is full of beer. Finally, attach the transfer line to the recipient keg. The beer should start flowing immediately.
Eventually, the pressure will be equalized between the two kegs, so slowly open the Relief Valve until you hear the hiss of CO2 gas escaping so you can regulate the rate of the beer flowing into the recipient keg. Once everything is equalized, the Pressure Gauge should read about 2 to 4 psi lower than the Pressure Gauge on the CO2 tank hooked up to the originating keg.
As the transfer comes to an end, be careful to cut off the flow between the kegs so only liquid gets transferred. Allowing CO2 through the transfer hose will cause foaming in the recipient keg, and oxidation of your beer will happen if any air makes its way through the line. If any beer, or beer foam, makes its way into the Pressure Gauge or Relief Valve, it will be nearly impossible to clean….not that it happened to me or anything.
The Relief Valve I used show it was set to about 25 psi when the Pressure Gauge clearly showed the pressure in the recipient keg was between 8.5 & 9 psi…lesson learned! – Follow the reading on the Pressure Gauge instead of the reading on the Relief Valve. Heck, you may want to buy an unmarked Relief Valve instead.
As for using a Spunding Valve to capture enough CO2 to pressurize and carbonate a beer in a corny keg…that will have to wait for a future post.