Until recently, Portugal's traditional ewe’s milk cheeses were rarely found outside the country. Will travels to the rugged mountains of the north to find out more about the king of Portuguese cheeses, Serra da Estrela. Dating back to pre-Roman times, this ancient cheese is still made from ewe’s milk and curdled with the juice of cardoon thistles. After travelling south to look at some of its close cousins, Will then travels to the ruggedly beautiful island of Sao Jorge in the Azores to learn about the benchmark cheeses of “little Switzerland”.