Seltzer water can be an expensive and wasteful addiction. And for what, water and carbon dioxide? So I set off in search of a homemade fix.
There are a number of options out there. Starting from the most awesome, albeit unreal option: seeking out Walter the Seltzer Man, among the last of a dying breed of seltzer delivery men, delivering the finest seltzer in antique glass bottles (same as his father before him and his grandfather before that).
If we're being practical, however, you've got your Soda Stream and your iSi: counter-top appliances that cost anywhere from $75 to $175 and require canisters of carbon dioxide. Over time, depending on the extent of your seltzer habit, they will pay themselves off, and if convenience is what you want, this is the route for you.
But then there is the most inexpensive, least wasteful, and neatest way to do it: capturing the CO2 that yeast emits when it eats! Harnessing nature! Working with microscopic creatures to cooperatively build a beautiful beverage!
You can buy a system at My Pop Soda Shoppe for $75 (or on Ebay, maybe for less), or build your own for pennies. I purchased mine not realizing how incredibly simple it would be to build. All you would need is seven 2-liter plastic bottles, some plastic tubing and fittings, a couple clamps, and a pressure gauge.
Five of the bottles act as tanks to hold the carbon dioxide, one is a reactor tank in which you brew the yeast, and the last is your soda bottle.
In the reactor bottle, mix 1 package of yeast (or 1/2 cup of sourdough starter), 1 cup sugar, and enough warm water to fill the bottle to be about 3/4 full. Give it a good, thorough shake (with an extra, stand-alone cap), and attach it to your system.
Within a couple days your pressure gauge should reach 30psi, and you can start bubbling!
This video pretty much says it all. However, I do find that I sometimes need to open the bottle a couple times during carbonation to let the air out, allowing for more carbon dioxide to flow in.
I usually drink the carbonated water straight, or with a wedge of lime. But there are a million possibilities... if you like drinking soda, experiment with different types of sugars, fruit juices, extracts (vanilla, mint, orange, almond, etc.), fresh herbs, teas, milks, however the spirit moves you.