I’m no fan of a watered-down cocktail, but sometimes a little carbonated H2O is the secret ingredient for perfecting your drink. It acts as a diluent, making some drinks easier to swallow. There are lots of carbonated waters out there, so how do you know which kinda fizz is the shizz (sorry, I couldn’t resist) for your cocktail in question?

First, we should probably cover what’s included in the category of carbonated/soda/fizzy/bubbly/sparkling water. Anything that’s classified this way is effervescent from dissolved carbon dioxide gas under pressure. Sparkling mineral water, seltzer, club soda, and tonic are all carbonated waters, but there are distinct differences between these varied types, including ingredients, carbonation method, flavor profile, and uses. Some info, distilled:

Mineral Water

Mineral water, sourced from natural underground springs, needs to have at least 250 parts per million (ppm) naturally occurring dissolved mineral solids to earn its “mineral water” label (instead of plain old “spring”). It can be flat (like Volvic) or sparkling (like Perrier) and, if the latter, is naturally carbonated. Mineral water contains dissolved minerals like salts and sulfur compounds that lend a subtle flavor and heavier mouthfeel and, though it looks and tastes like seltzer water, it tends to be more expensive.

Seltzer Water

Seltzer water is simply unflavored spring water that’s been artificially carbonated with carbon dioxide—no other additives are included. It’s often considered a calorie-conscious alternative to sweetened sodas, and is inexpensive to both buy and make (with tools like a Sodastream, or an antique seltzer bottle). Fun fact: it’s named after Niederselters, a town in Germany known for its natural springs from which carbonated water has been commercially bottled and shipped since at least the eighteenth century.

Club Soda

Club soda and seltzer are often used interchangeably in cocktails, but they’re not exactly the same thing. Club soda is actually similar to mineral water in that it contains many of the same compounds (like sodium bicarbonate, sodium citrate, disodium phosphate, potassium bicarbonate, and/or potassium sulfate), but they’re artificially added in addition to carbonation. This slightly more, uh, mineral-y taste is still pretty clean, though, so club soda is as suitable a mixer for highball drinks as seltzer, for which it can be substituted (and vice versa).

Tonic Water

Okay. So tonic water is actually entirely different from the other kinds of waters that have been mentioned, but it’s still carbonated water! It doesn’t taste particularly watery, but instead has a discernibly bitter flavor that comes from the addition of quinine, a compound sourced from the cinchona tree, which pairs especially well with gin. Tonic also contains calories—it’s sweetened with either sugar or corn syrup.

Thirsty for more knowledge? You may be interested to know that English chemist Joseph Priestley first artificially carbonated water in 1767, but German watchmaker Johann Jacob Schweppe was the one to simplify a carbonation method in 1783 that allowed him to mass produce it. Ultimately, soda water contributed to a culture of social drinking: instead of drinking liquor straight up, people incorporated diluents into their drinks, thereby easing the absorption of alcohol and subsequently making drinking more socially acceptable.

Still not quenched? Hydrate with some recipes here or (if you’re feeling especially cultish) here.

Now excuse me while I go search for my own tall glass of water . . .