In March 2011, Michael Vachon, an American expatriate working for a struggling tech start-up business in London, was in Austin, Tex., for the South by Southwest festival, trying to drum up interest in his company. He was eager to try it: Upstart American distilleries like Ransom were all the talk at the high-end bars he frequented in Britain, but because those distilleries didn’t distribute their products there, they were vanishingly rare.