"Waiter, There's a Herb in my Beer"

When Fal Allen expresses a fondness for beer, he doesn't just mean sipping suds in an air-conditioned bar with other members of Singapore's expatriate community. Instead, the 46-year-old American has the kind of passion that drives a man to try unexpected paths—in his case, the ones that lead to the Lion City's stiflingly hot open-air markets, where he sniffs handfuls of potent spices and quizzes stallholders on the flavors they yield. His mission? To find Asian beer's next big ingredient.

As brewmaster of Singapore's Archipelago Brewery, archipelagobrewery.com , Allen is tasked with identifying which Asian herbs and...