Single origin sounds like one farmer on one misty hillside, but the only baseline requirement is coffee grown within a single known geographic origin, and no universal body polices the label. A few producing countries, such as Brazil, regulate their own exports, but internationally the term is loosely applied. That means a whole nation can count as one origin: beans from Brazil’s tropical north and temperate south can be mixed and still legally sold as single origin, and the same goes for Colombia or Vietnam. The episode sets this against grocery store blends, which combine beans from several regions to taste identical year after year, and against the symbolic value roasters create by naming producers and origins on the bag.

In the middle sit estate coffees, grown on one farm ranging from dozens of acres to many square miles, or on many small farms that pool their harvest and process it at one central mill, a model common in Colombia, Brazil, Costa Rica, and Mexico. At the far end are microlots: one field, a narrow band of altitude, and a single day’s harvest, sold at steep premiums. Because paperwork can be forged and sacks swapped, researchers are now building DNA fingerprints of coffee trees to verify where green beans really came from.

• Starbucks combines many small farms in the Philippines into a single estate-style cooperative.
• A central mill standardizes fermentation, washing, and drying, removing the variables of a hundred separate drying tarps.
• Rain the day before picking can swell cherries and dilute their sugars, so a single-day harvest freezes one set of conditions.
• DNA is extracted from the silver skin or inner tissue of green beans and multiplied through PCR amplification.
• Scientists swab leaves from mother trees on farms to build a genetic database for buyers to check samples against.