The valley makes about three-quarters of Mexico's wine, and visiting it means driving between fifty-odd wineries scattered across gravel roads, most of which want a reservation rather than a drop-in. Decide in advance or you will spend the day at the three with a car park.
Book a driver. The distances are short, the roads are unlit and unsigned, and the Baja drink-driving enforcement is real. Operators run from Ensenada, Tijuana and San Diego; the Ensenada ones are cheaper and start later.
What to taste: the valley's best wines are usually the Bordeaux reds on the El Porvenir side and the increasingly good nebbiolo, which Baja grows better than it has any right to. A number of younger producers work with minimal intervention and wild yeast.
The food is as much of a reason to come as the wine. The valley's open-air kitchens — Deckman's, Fauna, Finca Altozano, Corazón de Tierra — cook Baja produce over wood and are booked weeks ahead at weekends.
Harvest, the Fiestas de la Vendimia, runs through August and the first half of September and fills everything. Spring and late autumn are quieter and the valley is greener.