What is the difference among club soda, seltzer, and sparkling mineral water, and can they be used interchangeably?
Club soda and seltzer are both made from water charged with carbon dioxide to give them bubbles. Club soda often contains sodium bicarbonate. In contrast, mineral water gets its more delicate effervescence from naturally occurring springs and, as the name suggests, contains more minerals than the other water types.
To find out whether these three effervescent waters could be used interchangeably, we tasted Polar seltzer, Schweppes club soda, and Perrier mineral water straight up and in our Shrimp Tempura, a dish where the fizz of seltzer plays an important role in the development of an ethereally light batter.
Sipped from the bottle, the seltzer had a neutral taste, the club soda had a slightly acrid bite, and the mineral water had a subtle salty earthiness that tasters preferred for drinking. In the tempura, club soda and seltzer both made a crisp, perfectly light crust that evenly coated shrimp. Mineral water, however, produced a thin, weakly adhering batter that fried up soggy. We attributed this to the fact that mineral water contains less gas than club soda and seltzer. The higher carbonation in club soda and seltzer makes the batter light and more aerated. It also does a better job inhibiting gluten development—in tempura batter, weaker gluten means a lighter, less bready crust.
Our conclusion: Club soda and seltzer can be used interchangeably in recipes, while sparkling mineral water is better for drinking.