Ken Grossman is working the taps. Clad in a trucker cap, blue jeans and Keen sandals, the 60-year-old is doling out samples of Hoptimum and Harvest Single Hop, two imperial pale ales made by his Sierra Nevada brewery. For many of 3,300 people who’ve paid $65 to attend the Portland, Maine, beer tasting with 117 breweries, Grossman’s the star attraction. “It’s an honor to meet you,” says a brewer from Newington, New Hampshire, reaching the front of the line. The attendees, mostly men in their 20s and 30s, many wearing beer brand t-shirts and some sporting long necklaces of pretzels, represent the core consumer of craft beer, an industry of 2,800 breweries that commands 14 percent of the $100 billion spent on beer in the U.S. each year. When Grossman started, there were just 40 breweries of all stripes in the country, with sales dominated by Budweiser, Coors and Miller. “It’s been a pretty phenomenal last 30 years for the American craft beer industry,” said Grossman in a July interview at his Chico, California, headquarters. He’s gone from storing beer in his grandmother’s fridge to the head of the country’s second-largest craft brewery, becoming a billionaire in the process, according to the Bloomberg Billionaires Index.