Lately I’ve been really intrigued with the concept of spunding valves. A spunding valve is like an air regulator that you attach to the gas port on a closed fermentation vessel. It is generally adjustable and you can dial in the point at which it will release the excess co2 to the air. Something like a spunding valve is necessary in order to do pressurized fermentation.
OK, but why?
Brewers use these during secondary or the end of primary to carbonate the beer while it is finishing. It has the benefit of skipping (or combining) the force carb step, and that means that you can go grain to glass faster!
There are a few different ways to build one of these. Here is an article from BYO, here is a post from homebrewtalk, and here is a ready to buy version from morebeer. All of those cost around or a little over $30.
Not to say that those won’t work, but I’ve got an idea that I think will make life easier, with fewer fittings to buy, and a few more features. I’m going to get one of these airbrush pressure regulators and take it for a spin.
Not only is it a bit cheaper (only $17), but it also has a built in water separator. That would allow any excess foam that might get picked up by the gas out port to not get to the regulator. It also has a big, easy to read dial, and a nice big knob to set the pressure with, as opposed to the small brass knobs or flathead screws on some of the other versions.
OK, but why, again?
A few reasons, really. It’s a cool idea. It seems like it saves a step. It means that the beer is ‘finished’ faster, so beers that are meant to be consumed fresh (ie super dry-hoppy ipas and a few others) can be consumed even fresher. It also has some evidence that pressure slows yeast activity and therefore can allow a fermentation at a higher temp without putting out lots of esters or other bad stuff. Like a lot of things in homebrewing it is simply a different way of doing things, and could be a fun adventure!
One thing to remember about these is that the corny kegs generally need a little starting pressure to seal up properly. Otherwise it may slowly leak and never seal to the point that the valve starts working. The best way to do that is by hitting it with a bit of co2 from the tank. If you charge it with more pressure than the spunding valve is set to, then you should hear it release pressure.
I’ll report back with more info once I put it into use!