Jesse Diaz started roasting beans in a $7 popcorn popper.

Today, in a room above his Ukrainian Village coffee shop, Star Lounge, Diaz (pictured) roasts small batches of Dark Matter coffee in a larger version of the same thing--an air roaster that he feels yields greater nuances (like peanut butter flavors in his Indian Robusta-Ethiopian Harrar-Sumatra Mandheling blend).

Zealous devotion to coffee is nothing new for Chicago. But Diaz's encyclopedic knowledge and meticulous oversight of the entire process--from bean sourcing to roasting to choosing the right brewing method (Star Lounge employs at least four)--makes Dark Matter some of the city's geekiest.

And one of the most aspirational: Diaz's goal is to eliminate middlemen and get all his beans directly from farmers. He hopes to head to El Salvador next month to visit plants being grown especially for him. Then it's on to Guatemala in search of new farmer relationships (and beans).

Bags of Dark Matter coffee are always available at Star Lounge, but there's no set menu of offerings. It changes by season--even by week--because, as Diaz is fond of saying, "Coffee's too complex of a substance to make concrete rules."

Dark Matter coffee beans are for sale (and brewed) at Star Lounge, and used at Kith and Kin, Browntrout, Alinea and The Drawing Room.