Is there a difference between seltzer water and sparkling water?
It depends on the sparkling water. If it is a naturally carbonated water, like Perrier or San Peligrino, it may have more natural minerals than seltzer water made from tap water. Club soda, on the other hand, frequently has salt added to it.
Same as tonic water? Yesterday a stranger in the grocery asked me where tonic water could be found. We were already standing in the aisle with the seltzer and club soda, but I didn’t see anything labeled as tonic water. I figured it was all basically carbonated water and suggested he try club soda as a substitute.
Tonic water is soda water with quinine added for flavor. It fluoresces a pretty blue under UV.
Tonic water has a very strong, distinctive flavor, not like club soda at all.
According to Wikipedia (and Merriam-Webster), “The term seltzer water is a genericized trademark that comes from the German brand Selters, which is produced and bottled in Nieder-Selters, Germany.” While I (among many others) distinguish soda water from other carbonated waters (“it ain’t soda if there’s no sodium!”), there’s no clear distinction in US usage between sparkling water, carbonated water, soda water, seltzer water, and club soda. AFAICT, it’s a tug-of-war between how it’s made, who made it, and what it’s used for that determines what name gets on the label.
Nomenclature. “Sparkling Water” usually, though not always, denotes natural carbonation. San Pellegrino is naturally carbonated, but indirectly; there’s a different, hypercarbonated spring they use to put the bubbles in.
Otherwise, depends on locale. “Seltzer Water” means water with CO2. “Club Soda” means water with CO2 and NaCO3. “Tonic Water” means water with CO2 and quinine (good for malaria, by the way, hence the “tonic”).
That’s just one set of definitions.