There are dozens of varieties of blue cheese. The four classics are French roquefort, English stilton, Italian gorgonzola, and Spanish cabrales. But today, blue cheese is made in many countries and in a growing variety of styles.
All blue cheeses are made by introducing a Penicillium mold into the milk during the cheesemaking process. Once the cheese is formed into wheels, cheesemakers use long needles to spike the cheese, creating veins where oxygen allows the blue cheese mold to grow. Beyond this basic process, different types of blue cheese are made by using different kinds of milk, temperature levels, amounts of salt, time for aging, and various other factors. Creamy blue cheeses have cream added to the curd during the cheesemaking process, while crumbly blue cheeses are created by aging the cheese to reduce the moisture content.