Early last year, an editor asked me to review and rank home carbonators—those countertop machines that turn chilly water into lovely seltzer. Research quickly revealed an industry in chaos. Some brands were plagued with deservedly horrible reviews or simply didn't sell. One, with a tendency to explode, was recalled. SodaStream made carbonators that some people liked and had politics that some didn't. It got so complex, I needed a spreadsheet to keep track of it all.
I soon wrote back to the editor, advising against doing a story.
I've owned a SodaStream Fountain Jet for several years and have found it to be a reliable machine for carbonating water. Say, an 8 out of 10 on the WIRED scale. With large, exchangeable CO2 canisters, it's more environmentally friendly than buying plastic bottles of store-bought fizzy water, or the tiny, individual-use chargers like those used with old-school seltzer bottles and whipping siphons.
My beef is that it only carbonates water. Carbonate anything else and you'll not only void your warranty, you'll understand exactly why. Try to pull a bottle of, say, orange juice from the machine and it will instantly fill with foam and launch sticky juice into the guts of the machine, an unholy mess that can only be avoided by waiting (and waiting) for the foam to die down.
For bartenders and cocktail aficionados, carbonating more than water is an exciting prospect. It means everything can be carbonated, not just the soda water poured into the drink. It also adds a pleasing nip of acidity and—busy bartenders love this—it can all done ahead of time.
Due to all this, bartenders like Jeffrey Morgenthaler in Portland, Oregon, used a Twist 'n' Sparkle (the one with a tendency to explode), long after it was recalled simply because there wasn't a better option out there. People learned the clumsy process of sloooooooowly venting pressure out of their SodaStream bit by bit to keep the foaming to a minimum. It was a mess, and it was slow, but it worked. The drinks were good.
Back in early 2015, one of the foundering brands on my spreadsheet was the iSoda carbonator. Now rebranded as the DrinkMate, it looks and acts quite a bit like a SodaStream. Rather amazingly, the DrinkMate uses SodaStream's CO2 tanks, which you swap out at participating retailers. This is understandable, as it lets a small company like iDrink (DrinkMate's manufacturer) skip figuring this part out, but at SodaStream's standard—and somewhat pricey—$15 for the 30 liter refill, it's a shame.
The key difference is a collar, which iDrink calls the "fizz infuser," that is on top of the bottle and comes right off with the bottle when you slide it out of the machine after carbonating. Many things happen at this point in the carbonation process, particularly one that differentiates the DrinkMate from its competition, so let's pause here for a brief Moment of Science.
Carbonating is the act of cramming carbon dioxide (CO2) into a liquid, supersaturating it by using pressure. The colder the liquid, the better this works.
Like fans streaming out of a stadium after a buzzer beater, when you initially open a pressurized container of carbonated liquid, the contents rush to come to equilibrium with the world around them. This effect is much more pronounced when it's something other than water in the bottle. Stuff like juices, wines, cocktails, or beer wreaks foamy havoc inside—and outside—a SodaStream if you open it quickly.
Try to remove a SodaStream bottle filled with, say, carbonated wine and you can very easily paint the walls, the ceiling, the inside of the machine, and yourself with it. You can get around this by finessing it off, controlling the pressure release by letting little bursts of air out, then waiting for the foam to subside, and doing it over and over again until you can coax it off without the foam overflowing. It's slow and inelegant, but it usually gets the job done.
This is where the beauty of DrinkMate kicks in: that collar/fizz infuser has both a slow and fast release valve, allowing what's inside to work its way back to equilibrium in an orderly manner. To go back to the stadium example, a fast release (SodaStream's only option) is like someone yelling "Fire!" while everyone stampedes toward the doors. DrinkMate's slow release, on the other hand, is like everyone filing toward the exits in an orderly fashion.
Once you've poured carbonated liquid into a glass, bubbles form around what's called nucleation sites—imperfections in the glass or a bit of microscopic dust in the liquid—that, say, leave an enticing trail of bubbles in a glass of Champagne. A rough-surfaced ice cube will cause more intense bubbling. Mentos, with all their micro-craters, create chaos in Coke or any other carbonated drink.