the.com/club soda

Water that went to business school and now charges more for bubbles.

means Carbonated water, sometimes with a pinch of added minerals, used plain or as a mixer for drinks.

from The 'soda' in soda water traces to sodium carbonate, once used in making the fizzy stuff; 'club' was tacked on in the 19th century as a brand-style flourish, evoking the gentlemen's clubs where such refined, bubbly water was fashionably served alongside the whiskey.

actual contents
filtered water plus minerals like sodium bicarbonate
vs seltzer
seltzer is just carbonated water, no minerals added
stain myth
does not actually remove wine stains better than plain water
origin
named for private clubs that first served it, 1870s
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