How we tested
Sparkling water is having a moment right now. Sales of bubbly water have nearly tripled over the last 10 years, and trendy brands such as La Croix have used clever branding and beautiful packaging to give this relatively simple beverage a whole new life. Gone are the days when supermarket sparkling water options were limited; now you can buy your water in enticing flavors such as coconut, peach pear, pineapple pomelo, or even “mermaid songs” and “unicorn kisses.”
Beverages become bubbly when there is gas in the liquid—usually carbon dioxide—which either comes from natural sources or is added artificially. Many mineral springs are a source of naturally carbonated mineral water; the gas that forces the water through the ground lends it an effervescence. All artificially carbonated water is made by injecting pressurized carbon dioxide into the water. At the supermarket you’ll find sparkling water sold under a number of different names: sparkling mineral water, club soda, and seltzer.
For this tasting we left out club sodas because they have prominent flavor compounds and are most often served as cocktail mixers. We focused on sparkling mineral waters and seltzers, which have a more mild flavor and can be used as an ingredient for providing lightness to battered foods like tempura or fried fish. We selected six nationally available, top selling mineral waters and seltzers. Though many of the brands we tried also offer flavored products, we opted to sample their plainest product so that we could best focus on the natural flavor and effervescence of the water, and because plain sparkling water is what we use in our recipes. Our lineup consisted of three sparkling mineral waters and three seltzers priced from $0.03 to $0.09 per ounce.
Though none of our waters had any added flavorings, we still noticed an array of flavors in them—from saltiness, to acidity, to a slightly sweet aftertaste. The three mineral waters had the most pronounced flavors by far. Many tasters were able to identify them in our blind tasting because they had a characteristic salty and sometimes sulfurous, almost eggy flavor. While manufacturers aren’t required to disclose the type and amount of minerals in their water, our science editor explained that two common compounds found in mineral water are sodium and sulfites, which can lend salty and eggy flavors, respectively. Tasters were split on the more pungently flavored mineral waters. Some loved the distinctive earthy taste, while others found the flavor too prominent. Ultimately, most mineral waters landed at the bottom of our rankings; our tasters preferred cleaner, more neutral options.
However, one mineral water—Topo Chico Mineral Water—earned the second-place slot in our tasting. We thought that it had slightly sweet and subtly salty taste that appealed to our mineral water lovers, but wasn’t overwhelming for those who prefer a more neutral drink.
Carbonation Adds Tartness
Carbonation also adds flavor to water. When carbon dioxide dissolves in water, a small amount of carbonic acid is formed, which gives the water a tart taste. That’s why sparkling water that’s gone completely flat doesn’t taste like tap water and still has a slightly sour taste—there’s still acidic carbonic acid in the water even after all the bubbles have left. Of course, carbonation also adds the characteristic fizzy sensation that sparkling water is known for.
Our carbonation-loving tasters gave higher ratings to products they perceived as bubblier. To get a better measure of the carbonation levels, we sent the sparkling waters to an independent lab to measure pounds per square inch (PSI). PSI is a common measurement of pressure and its often used to measure the amount of gas in a bottle of champagne. The higher the PSI, the more gas is in the product. Our sparkling waters ranged from 38 to greater than 60 PSI when tested at room temperature. These results mirrored our tasters’ preference for higher carbonation: the product with just 38 PSI was too flat for most tasters—our favorite products had at least 43 or higher PSI and were “pleasantly bubbly.” (Note: Some products we tasted come in both cans and bottles, which may have slightly different PSIs. The PSI reported is for the packaging shown in the photo.)
The Best Sparkling Water: Polar Original Seltzer
In the end, our favorite sparkling water was also the least expensive. At just $0.42 per can, Polar Original Seltzer took home top honors for its strong but balanced fizz and clean, neutral flavor. If your sparkling water must have the salty tang of minerals, we can also recommend Topo Chico Mineral Water ($1.08 per bottle), though it’s a bit bubblier than some tasters would like.
Twenty-one America’s Test Kitchen staffers sampled six top-selling nationally available sparkling waters at room temperature: three mineral waters and three seltzers, priced from about $0.03 to about $0.09 per ounce. PSI were analyzed by an independent lab and are reported below. The instrument the lab used to evaluate PSI cannot measure above 60 PSI, so larger ratings are reported as “greater than 60 PSI.” Prices shown were paid in Boston area supermarkets.