New Delhi, Aug. 8 -- The road into Arenas de Cabrales winds through emerald valleys where cows graze beneath soaring limestone peaks veiled in mist. For gourmands, it's synonymous with Cabrales: Spain's funky, cave-aged blue cheese so distinctive that it holds a Guinness World Record. In 2024, a wheel of Cabrales fetched €36,000 at auction, making it the world's most expensive cheese ever sold. But the real story lies in the generations of families working tirelessly to preserve this tradition.

It's a crisp June morning, and I join my fellow train passengers from the Costa Verde Express on an excursion to Vega de Tordin, a sixth-generation family-run cheesemaker on the outskirts of the village. The dairy is modest-whitewashed walls...