Stilton is produced in two varieties: white and blue. Blue has penicillium roqueforti added to generate a characteristic smell and taste. Both have been granted the status of a protected designation of origin (PDO) by the European Commission, requiring that only such cheese produced in the three counties of Derbyshire, Leicestershire and Nottinghamshire may be called Stilton. The cheese takes its name from the village of Stilton, now in Cambridgeshire, where it has long been sold. Stilton cheese cannot be made there because it is not in any of the three permitted counties.
Frances Pawlett (Paulet), a cheese maker of Wymondham, Leicestershire, has traditionally been credited with setting up the modern Stilton cheese shape and style in the 1720s but others are named. Early 19th-century research published by William Marshall provides logic and oral history to indicate a continuum between the locally produced cheese of Stilton and the later development of a high turnover commercial industry importing cheese produced elsewhere, under local guidance. A recipe for a Stilton cheese was published in 1726 by Richard Bradley, later first Professor of Botany, Cambridge University.
Another early printed reference to Stilton came from William Stukeley in 1722. Daniel Defoe in his 1724 work A Tour thro' the Whole Island of Great Britain notes, "We pass'd Stilton, a town famous for cheese, which is call'd our English Parmesan, and is brought to table with the mites or maggots round it, so thick, that they bring a spoon with them for you to eat the mites with, as you do the cheese."
According to the Stilton Cheesemaker's Association, the first person to market Blue Stilton was Cooper Thornhill, owner of the Bell Inn in Stilton, Huntingdonshire (now in Cambridgeshire). Tradition has it that in 1730, Thornhill discovered a distinctive blue cheese while visiting a small farm near Melton Mowbray in rural Leicestershire – possibly Wymondham. He fell in love with the cheese and made a business arrangement that granted the Bell Inn exclusive marketing rights to Blue Stilton. Soon thereafter, wagonloads of cheese were being delivered there. The village stood on the Great North Road, a main stagecoach route between London and the north, so Thornhill could promote sales and the fame of Stilton spread rapidly.
In 1936 the Stilton Cheesemakers' Association (SCMA) was formed to lobby for regulation to protect the quality and origin of the cheese. In 1966 Stilton was granted legal protection via a certification trade mark, the only British cheese to have received that status.
Blue Stilton's distinctive blue veins are created by piercing the crust of the cheese with stainless steel needles, allowing air into the core. The manufacturing and ripening process takes some 9-12 weeks.
For cheese to use the name "Stilton", it must be made in one of the right county and use pasteurised local milk. PDO was grabted in 1996. The cheese remains protected by its PDO even after Brexit. Some six dairies are licensed (three in Leicestershire, two in Nottinghamshire, one in Derbyshire). Four are based in the Vale of Belvoir.
On average, finished Stilton cheese has a typical fat content of 35% and protein content of 23%.