Archives for the ‘home carbonation’ Category

home carbonation

I love seltzer, but I don’t love spending money on bottled seltzer and carrying 50lbs of it home at a time. I recently bought a CO2 tank and regulator for the keg at Crushtoberfest, and I’ve been looking for other uses for it ever since.

It turns out that making seltzer at home is very easy, and once you have the basic equipment the cost-per-bottle is extremely low. Here’s how I set it up:

home-made seltzer

The tank and regulator kit are from Micromatic. The rest is just a handful of fittings from McMaster-Carr, screwed into a hole drilled into a seltzer bottle cap. Here’s the parts list:

part #
part source
1 1 5lb. aluminum CO2 tank, empty
2 1 tank filling
local welding supply store
about $10-15
1 double gauge CO2 primary regulator
3′ red vinyl gas hose – 5/16″ ID
2 hose clamps (pack of 10) – part #5388K14 McMaster-Carr
6 1 Brass Barbed Hose Fitting Adapter for 3/8″ Hose ID X 1/8″ NPTF Female Pipe (pack of 10) – part #5346K34 McMaster-Carr
1 Lincoln-Shape Hose Coupling Plug, 1/8″ NPT Male, 1/4 Coupling Size – part #91455K51 McMaster-Carr


1 Lincoln-Shape Hose Coupling Socket, 1/8″ NPT Male, 1/4 Coupling Size – part #91455K52 McMaster-Carr


9 1 Electric Panel Hex Nut 18-8 Stainless Steel, 1/8″-27 Nps – part #91862A306 McMaster-Carr
1 bottle cap
your recycling bin
several empty one, two, or three liter bottles
” ”


* you may need to turn this in for a full tank, although some places will fill your tank while you wait
** I bought a good one, you can get these cheaper
*** unfortunately you sometimes have to buy 10 packs (or more) from McMaster. You can get individual hose clamps from your local hardware store.

Here’s how it goes together:

I drilled a hole in the cap (#10) that was just big enough for the threaded end of the coupling socket (#8) and assembled them together with the nut (#9). I used teflon tape in between parts 6 and 7. I also use my CO2 bottle for a keg when necessary, so I got a second set of part 6 and 8 and attached it to the hose coming from the keg tap. This way I can connect and disconnect from one system to the other.

One thing I learned, and this is VERY IMPORTANT: Apparently there is a chemical reaction between the CO2 dissolved in water and copper (or copper alloys like brass) that creates a toxic substance that will make you sick. Never use brass or other copper-based fittings with seltzer! All of these fittings (or at least the ones that will be in contact with the seltzer for any length of time) are either zinc-plated steel or stainless.

The carbonating process is simple. Fill an empty bottle with the liquid of your choice and refrigerate it. Replace the cap with the special one you made and attach the quick-disconnect hose to it. Make sure the shutoff valve on the regulator is closed, then slowly open the main valve on the tank until the regulator shows pressure. Adjust the output pressure to about 45psi and open the shutoff valve, pressurizing the bottle. Now loosen the cap on the bottle just slightly while squeezing any air space out of the neck of the bottle, then tighten the cap. This will purge any air from the bottle and replace it with CO2. Now shake the bottle vigorously for about 20-30 seconds; this will help dissolve the CO2 into the liquid faster. Shut off the CO2 at the regulator and disconnect the hose from the quick-disconnect fitting. You can now remove the special cap (slowly, the contents are now carbonated!) and replace it with a regular cap.

So on the first day I made seltzer water. On the second day I carbonated apple juice, grape juice, and Gatorade, and ended the evening with a carbonated vodka martini (nice!). What else can I carbonate?