Hard seltzer became a billion-dollar industry in the late 2010s, but it was invented in 2013 by Nick Shields in Westport, Connecticut. The drink is made through a process of fermenting sugar (usually cane sugar) rather than malted grains. This results in a very 'clean' alcohol base that is then filtered to remove all color and flavor. Because there are no grains involved, hard seltzer is naturally gluten-free and significantly lower in calories than beer. The 'fizz' is achieved through carbonation, and natural fruit flavors are added at the end. The science behind its popularity is 'sessionability'—the combination of low alcohol content, low sugar, and high carbonation, which makes it easy to drink over long periods without the 'heaviness' of beer or wine.