In the final scene of Casablanca, Claude Rains' character, Captain Renault, picks up a bottle of water and pours some into a glass. He banters with Humphrey Bogart's fascist-fighting Rick Blaine about patriotism for a moment before noticing the bottle's label: Vichy water. He promptly drops it into the trash and kicks the basket over. This isn't because Renault was a LaCroix loyalist or was wishing that Topo Chico shipped to Morocco. The policeman had operated as a puppet of the French protectorate's Vichy government, which was essentially a tool of the Nazi regime. With that symbolic gesture, Renault demonstrated that he couldn't find their politics—or their water—to be something he could swallow any longer. It's a memorable (and timely) moment from a cinematic masterpiece (that's the same scene that gave us "I think this is the beginning of a beautiful friendship.") but also: What the heck is Vichy water? 

For centuries, humans have made pilgrimages to thermal and cold springs along the Allier River in the town of Vichy, France, hoping to benefit from the supposed healing powers of their mineral waters, rich in sodium bicarbonate as well as other alkaline salts. Not all of the water is especially delightful to drink, but it's ideal for filling baths and pools for spa treatments. Some springs, however, produce potable water—both still and naturally carbonated—that's bottled and sold as Vichy water. Some of these waters are available with a medical prescription at the town's Hall des Sources, but perhaps the best known—Vichy Célestins—has its natural carbonation augmented with carbon dioxide, and is available to the public. 

But that doesn't mean all Vichy water you see on the shelves comes from that precise geographic location, because it doesn't have an appellation d'origine contrôlée to restrict the use of the name. In 1903, La Compagnie Fermiere de l'Etablissement Thermal de Vichy (a.k.a. the Vichy company) petitioned the circuit court of the United States for the Northern District of New York to disallow the Saratoga Vichy Spring Company from using the word Vichy, claiming that it was their commercial name and trademark. Saratoga, which had been using the term since 1872 when a town spring was found to have the same properties as French Vichy water, countered by saying that the plaintiff's claim was "stale," that they'd been selling the water for 50 years, and "such name has come to denote a type of water, namely, alkaline, noncathartic, carbonated water, and does not stand for the water of any one spring." Saratoga prevailed and bottled its own Vichy water until 2000 when sales began to fizzle.

Vichy Catalan, as one might assume, bubbles up warm from a source north of Barcelona and contains plenty of sodium bicarbonate and other minerals that give it that distinctive Vichy water saltiness. It's been cooled and bottled at the source since 1881 and is popular throughout Spain, bolstered by marketing that emphasizes its food-friendly pairing qualities. And yes, they were unsuccessfully taken to court by the French as well. Hartwall Vichy has held down the fort in Finland since 1836. 

Fizzy-water cultists have something of a fixation with Vichy Catalan, but it’s tricky to find in the US. Polar, which is far better known for its range of seltzers and ginger ales, offers a "traditional" and "premium" Vichy water with the listed ingredients of carbonated water and mineral salts. A guide on the Polar mixers website recommends pairing it with Campari or caramel to temper bitterness or enhance sweetness. Vichy Springs—a resort that been in business in Ukiah, California, since 1854—claims that drinking the highly alkaline water from its springs "soothes acidic digestive systems and aids and cures gout, rheumatism, ulcers and all sorts of acid related illnesses," but doesn't sell it directly to the non-spa-going public. Presumably, a person hard-up for a Vichy fix could trek to their local purveyor of Vichy brand beauty products and fork over $24 for 200 milliliters of the brand's Aqualia Thermal Hydrating Water, but they also might be better off sticking to the on-label usage of it to provide an "extra layer of hydration and prepare your skin for moisturizers and serums." It might just be the beginning of something beautiful.