What causes some cheeses to develop blue veins?

The development of blue veins in certain cheeses is primarily caused by the presence of Penicillium roqueforti mold. This specific mold is a key ingredient in the production of blue cheeses, such as Roquefort, Stilton, and Gorgonzola. During the cheese-making process, the mold is introduced either through spores or by including already contaminated curds.

As the cheese matures, the mold grows within the cheese, and the anaerobic conditions create the distinctive blue-green marbling. The mold breaks down fats and proteins in the cheese, contributing to its unique flavor profile and characteristic aroma. The process allows for the development of a complex taste that is both sharp and tangy, offering a sensory experience valued by cheese aficionados.

The other options, while related to cheese characteristics, do not directly account for the specific formation of blue veins. High fat content influences the texture and creaminess of the cheese but does not create the blue coloration. The fermentation process is essential for cheese making in general but isn't responsible for the distinctive blue marbling. Lastly, brine soaking can affect flavor and texture but is not involved in the actual blue veining itself.