Cheese is ripened by a series of complex physical, chemical and microbiological changes which incorporate the agents of bacteria and enzymes into the cheese.
Cheese ripening is known as maturation or affinage and is a controlled process in which the cheese is aged under specific conditions to allow the cheese to develop it's distinct flavor, texture and aroma.
The process occurs through the breakdown of proteins and fats by enzymes and bacteria.
The enzymes from rennet, milk and also microorganisms such as molds and bacteria play a critical role in breaking down of the proteins such as proteolysis and the fats called lipolysis that contribute to the flavor and texture development of the cheese.
Microorganisms such as molds, yeasts and bacteria that are also added and naturally occurring also contribute to the cheese ripening process and also influences the flavor, aroma and appearance of the cheese.
Temperature and humidity also play a role in cheese ripening as the temperature and humidity levels are carefully controlled to promote the growth of beneficial microorganisms and enzyme activity which influence the speed and the type of ripening of the cheese.
Moisture content also plays a role in cheese ripening and the moisture content of the cheese also influences the rate of ripening of the cheese, drier cheeses ripen slower than cheese with higher moisture content.
The types of cheese ripening include interior ripening which occurs from the inside out, often with cheeses that are coated in a rind or wax that protects the surface of the cheese such as Swiss cheese and cheddar cheese.
And surface ripening which occurs from the outside in, with the cheese developing a natural rind through the action of bacteria and molds, like Muenster cheese and Brie cheese.
The ripening time of cheese varies significantly depending on the cheese type, desired flavor and texture and can range from a couple of weeks to several years.
In cheeses such as Roquefort cheese, the blue veins develop from the growth of Penicillium mold.
And in Emmental and similar cheeses, holes form due to the production of carbon dioxide by Propionibacterium bacteria.
In cheeses like Limburger cheese, a red smear develops from the growth of Brevibacteriumn linens bacteria.
And in cheeses such as camembert and Brie cheese, a white mold, often penicillium develops on the surface and creates a bloomy rind.