Whether you’re making a highball or topping off an Aperol Spritz, sparkling water might just be the most all-purpose mixer in your cocktail-making arsenal. But not all of the bubbly stuff is created equal. Using club soda versus seltzer is an important consideration that can affect the cocktail you’re making.

Club soda, mineral water, seltzer, and tonic water all have varying flavor profiles and carbonation levels that will impart different qualities to a drink. These are the most common types of carbonated water and when you should reach for each as a cocktail mixer:

Seltzer is simply plain water that has been “carbonated” or injected with carbon dioxide. Its flavor is neutral. But many vodkas some producers add a wide variety of flavors, from lemon-lime to hibiscus. Hard seltzer, meanwhile, is made with an alcoholic base such as fermented cane sugar. Club soda is the most common component in bubbly cocktails, but you might swap in seltzer if you’re watching your salt intake, as the former contains about 75 milligrams per can.

Consider sparkling mineral water seltzer’s cousin who studied abroad. Bottles like Perrier and Badoit include naturally occurring bubbles from sources like springs and wells; sometimes additional effervescence is added artificially. Flavor profiles and bubble sizes will vary based on the terroir and the minerals naturally present in the source: Natural springs in the Italian Alps give San Pellegrino a touch of salinity, while a limestone spring in Mexico gives Topo Chico its bouncy bubbles and what some consider a slightly citrusy taste. Because of its higher price point, mineral water is usually sipped solo, but Texans swear by Topo Chico for Ranch Water, a cocktail of tequila, fizzy water, and lime juice.

You can use most sparkling waters interchangeably in a pinch, but that’s not the case with tonic water. Made with a base of soda water, the mixer gets its characteristic bitterness from the addition of quinine, a compound that comes from the bark of the Central American cinchona tree, once beloved for its antimalarial properties. Some producers add high-fructose corn syrup to balance the bitterness. Many premium brands (Fever-Tree, Q Mixers, etc.), employ less-processed sweeteners like cane sugar and agave. Tonic water is a natural match for gin and vodka, but you can use it any time you want to give a drink a bitter, bracing quality. Switch up your G&T with a White Port & Tonic or a Summer Tonic, a refreshing mix of rum, amaro, and aromatic tonic water.