Seltzer is water carbonated by the addition of carbon dioxide under pressure, the sparkling water also known as soda water or fizzy water. The name comes from Selters, the German spa town whose naturally sparkling mineral water was famous across Europe. Plain seltzer contains no sodium bicarbonate despite some definitions suggesting it; that confusion comes from soda water made with added bicarbonate. It is the mixer behind whisky-and-soda, the base of Italian sodas and spritzes, and a calorie-free alternative to soft drinks. Home carbonators now let households make it on demand. Served ice-cold with lemon, it is the simplest sparkling drink, and its clean fizz carries flavours without adding any of its own.