As cofounders of the innovative Zingerman's Deli­catessen, Paul Saginaw and Ari Weinzweig have spent the last two dec­ades building their reputa­tion by traveling the world in search of the best foodstuffs. But when it comes to coffee, there's no need to leave town. I meet up with computer programmer turned Zingerman's roaster Allen Leibowitz at work in his 1,000-square-foot niche of the 24,000-square-foot mail-order warehouse where one man and one machine roast about 40,000 pounds of coffee a year, 66 pounds at a time. But Leibowitz isn't in a hurry to change that. "Doing things on this scale gives me a better understanding of exactly what a specific bean likes in terms of heat," he says. "Some require low heat over a longer period in order to highlight their best characteristics." Take the India Coorgi: trial and error taught Leibowitz that the beans need to be roasted just slightly darker, at higher heat over a shorter period of time, to bring out the spiciness and hints of clove and mace. At this point, because of the quantity of beans he buys, Leibowitz is limited to working with brokers, instead of directly importing from producers, and relies on cuppings to become familiar with the taste of the beans. "We're not these firms' biggest customer, but they know we buy the best," he says. Of the 15 Zingerman's coffees, 12 are single-origin, like the thick and chocolaty Papua New Guinea. The remaining three are blends, including Roadhouse Joe, a slightly nutty mix with lots of body and no bite. The coffees are used throughout the Zingerman's businesses on a rotating basis. The Roadhouse blend is even featured as an ingredient in the restaurant's spicy tomato barbecue sauce. But the quirkiest place to get a cup—and give a nod to Detroit's car culture—is at Roadshow, a 1952 peanut-shaped Royal Spartanette aluminum trailer coach customized to look like a coffee pot. Roadshow is parked outside the Roadhouse restaurant, two miles from the deli, at the corner of Jackson Avenue and West Stadium Street. Pull up to the window and order your Roadhouse Joe with a cakey nutmeg-spiced doughnut rolled in Muscovado brown sugar.  The combination is sure to keep you driving in circles.
422 Detroit St.; 734/663-3354; www.zingermans.com.

After hatching their plans in a nearby pub, former baristas Todd Carmichael and Jean Philippe Iberti put a 15-kilo Vittoria roaster in the window of their café and went into the coffee business, cranking out enough smoke to season swanky Rittenhouse Square and attract the attention of the local fire department. Over the next 10 years, the partners made their creation a destination, a feat that impressed city officials so much that they affixed colorful French Quarter markers to the street signs on the café's corner. Making my way through the crowd inside—1,500 people a day get their coffee at the 28-foot-long turn-of-the-century mahogany bar—I find nothing for sale except coffee drinks: no muffins, wraps, or logo-emblazoned travel mugs. The partners are roasters, not retailers, and the strength of the company rests on four distinctive blends—ranging from the deeply rich and truly dark Corsica to the creamy and slightly sweet Nizza, which tastes delicately of caramel. There is little confusion about priorities. La Colombe coffee may be the choice of star chefs like Jean-Georges Vongerichten and Alain Ducasse, but every decision the partners make is in service to their blends. "Product first, customer second," Carmichael says. Loyalty is tied to the green coffee bean as a blend component, not as the product of a specific region: it's either a good note in the chord or it's off. Then comes the heat. Again, the partners stay committed to their four recipes. Instead of roasting the beans independently and then blending, the partners blend first and then roast. "Think soup," Carmichael says as he shows me the control panel behind the towering fluid air-roaster that turns out about 1.5 million pounds a year. "You wouldn't cook all the ingredients separately and then combine them. You find the right temperature to cook them together so their flavors mingle and marry."
130 S. 19th St.; 215/563-0860; www.lacolombe.com.