PEOPLE HAVE BEEN making wine in the verdant hills of northern Portugal’s Douro Valley for nearly 2,000 years. Nowadays, the region is home to more than 19,000 grape farmers and 1,000 companies tending terraced vineyards that tower above the Douro River below.
Hundreds of these vineyards are small, often family-owned, properties called quintas, many of which produce port: a syrupy, sweet fortified wine. As a European Union–protected designation of origin product (similar to French Champagne or Italian Parmigiano-Reggiano), the production, labeling, and sale of port are heavily regulated—sometimes to the detriment of the small-scale operators keeping the cultural practice alive.
When I visited the Douro Valley this fall, one quinta owner shared that she couldn’t officially sell port because of burdensome government regulations. All port sellers are required to keep…