Koch says that there is an economic explanation for the spread of craft beers—as a share of disposable income, a six-pack of fancy craft beer now costs no more than a six-pack of Bud did 30 years ago, due to a relative fall in food costs—and an even more important cultural one. “It’s the phenomenon of trading up,” he said, describing the process that in a generation has changed America from the country with the worst selection of good beers to the one with the best. “People want more variety. They are drinking less, so they want to drink better. They want interesting, complex flavors.” This force, he said, drove the interest in wine starting 30 years ago, in craft beer over the past decade, and in craft spirits more recently.

Boston Beer, the company that makes Sam Adams, went public in 1995, with the ticker abbreviation SAM. Based on his holdings, Koch is now a billionaire. No one goes as far in business as Jim Koch has without creating enemies, or at least critics. The main gripe about him boils down to a sense that he’s posing as a friendly small-town publican when he is actually big enough to muscle others around. Sam Adams’s sales are more than double those of its nearest craft-beer rival (Sierra Nevada, of California) and nearly triple those of the next-largest (New Belgium, of Colorado). Visitors soak in the Olde Boston charm of the Jamaica Plain brewery, but the largest Sam Adams production site is near Allentown, Pennsylvania. The IRS applies a lower tax rate to beer from breweries with output below 2 million barrels a year, a level unchanged since 1976. Sam Adams, whose output now exceeds 3.4 million barrels, no longer makes that cut. Koch, along with other brewers, has lobbied Congress to increase the ceiling to 6 million barrels, which would save Sam Adams millions of dollars in federal taxes per year.

As controversies go, this strikes me as, well, small beer. Koch points out that all craft breweries, together, make up well under 10 percent of total U.S. beer sales. Their sales and market share are rising quickly, while the major brewers’ sales have been going down, but the gap is still immense. “After 30 years of trying, we’re all the way up to 1 percent of national market share!,” Koch said. For comparison, Anheuser-Busch sells about 125 million barrels.

Koch didn’t tell me, but other craft brewers I interviewed around the country did, that he has gone out of his way to help small start-ups. A brewer in California said that during the disastrous (for the industry, and for devoted customers like me) world hops shortage of 2008, Koch shared some of his hops stockpile, at cost, with smaller brewers. One in Pennsylvania told me this summer, “I figure he created the business we’re living in. To me, he’s our Steve Jobs.” Koch’s differences in personality and background from Steve Jobs are obvious. Still, there is this parallel: Koch has made a very successful business out of satisfying a demand people didn’t know they had.