Any doubts over whether hard seltzer was just a “fad” were put to bed after last year’s sales figures came out: In 2019, U.S. drinkers bought more hard seltzer by volume than vodka. To be exact, we purchased 82.5 million 9-liter cases, or almost 2.1 billion 355-milliliter cans, according to global data firm IWSR. In the last 12 months, hard seltzer’s total share of the overall alcohol market in sales by volume rose to 2.6 percent — a small figure until you consider it’s more than a third of the total volume sales of all spirits, which stands at 6.8...