-longtime San Andreas Malt, Jack Dawson, takes brewing on the cheap to the next level;
Now you can have… free beer gas !
A couple years back, my sister sent me an Omaha Steaks Gift pack for Christmas. Amid the cow-cicles was a large slab of dry ice in protective plastic. After I chucked it, I began wondering if I could somehow find a way to capture it.
There were two factors driving this process. The first is my frugal nature. Friends have occasionally referred to me as a cheap bastard but it seemed a shame to waste all that potential beer gas. The second was the hassle of getting a CO2 tank refilled in San Francisco. The city council, in their infinite wisdom, passed a law years back stating that CO2 under pressure can only be transported in open bed vehicles. The last time I bought beer gas I had to grovel in order to be allowed to put a refilled 10 gal tank in a friend’s trunk. Since the hydro test date on that can now qualifies it for inclusion in a Smithsonian collection, and since I don’t own a car and can’t get outside of SF easily, I was forced to conclude I was S.O.L. But back to cheapness.
I have now successfully harvested dry ice from an Omaha Steaks delivery in mid-June and converted it into beer gas. As of today (September 13th,) I have pumped dry the two 5’s which were in the fridge then, a full 3 and 5 gal. keg, and am pushing 2-5 gal. kegs through now with that same dry ice I collected in mid June. I still have some of that gas and expect to completely pump the 2 kegs I’m currently tapping, plus. This is also my 2nd attempt and builds on mistakes and observations made during the first.
But first a legal disclaimer…Don’t do this at home! I am not suggesting anybody try this. There’s probably several dozen ways I could have, (maybe should have), earned a Darwin award doing this but…ignorance is bliss and goes very well with a homebrew.
The overall concept is, you put the dry ice in a dry, clean, sealed 5 gal Cornelius keg. As the dry ice melts, you connect another dry, clean, sealed keg to that one to capture the gas. Sounds absurdly simple…right? NOT!
First off, dry ice is incredibly cold stuff and you have to be careful working with it. I didn’t weigh the block I used but I’m guessing it was 2-3 lbs. It’s really dense stuff too. you will need way more kegs than you think because dry ice expands big time. I used oven mitts and a large screwdriver handle to break up the block into small pieces and dump them and the dry ice snow into the “mother keg” Do this in the sink, because the stuff is brittle and will shatter and go everywhere. Seal the keg. My keg began to scream and moan for a minute or so as, first the draw tube, and then the skin rapidly chilled. Within a few minutes I could see first solid frost, and later an inch thick coating of rhyme ice covering the bottom third of the keg.
You’ll need one, preferably two, special-use hoses with ball lock fittings at both ends to transfer gas. I have both an out-to-out, built originally for transferring beer between kegs, and a gas line which came with my first CO2 system meant to screw to a regulator, with a ball-lock gas fitting on that making it an in-to-in configuration. This is the one I use to pressurize the beer kegs with captured gas. You will also need several clean dry sealed kegs. Besides the mother keg I had 1 additional 5 gal. and 3 more 3 gal. kegs waiting to accept gas. I needed them all and only had to vent a minimal amount of excess gas. How much you get is determined by the storage capacity you use but remember also that a beer keg maxed out with gas is not available for beer.
I connected one keg each to the in and out sides of the ‘mother keg’. Almost immediately, I begin pulling the relief valve on all 3 kegs at intervals. I wanted to vent all the air in the kegs and only have (mostly) CO2. I did this for about 5 minutes. At intervals I swapped out kegs and moved others in so I could keep the overall pressurization even, doing the same early venting to purge air. As the kegs fill they get harder to work with as the hoses become harder to connect and disconnect. Eventually, as the kegs reach their design limits, the release valves will start to hiss on their own. This is where it’s important to release pressure in the mother keg, then the full keg, (just a short blast on each), and swap in lower pressure cans. As time passes and you check the mother you will hear the ice become slushy liquid as it melts. You’ll know you’re almost done when you shake Mom and don’t hear any slush or ice and the rhyme ice starts to melt from the top down. This whole thing takes a couple hours, and I was in a well ventilated place.
When I was done I had 2-5 gal and 3-3 gal kegs pressurized to just short of the keg’s design limit. What I should now ideally have to dispense the beer gas, is another special-use hose with an inline regulator. I dispense directly from one keg to another in my beer fridge using the “in to in” gas hose described above. This means I must be very careful when transferring gas to the beer keg as there is no regulation. I’ve learned to dribble gas in but occasionally I’ll tap a beer that tries to blow through the bottom of my beer glass and gives me a refreshing head-to toe shower. This can make drinking a homebrew an even more exciting experience and one I highly recommend. And free beer gas is almost as good as free beer.
