The cheesemaking process relies on the action of bacteria and rennet on properties in the milk, which transform the latter from its liquid state into a compact mass with a varying degree of solidity.
The process of transforming milk into cheese comprises 3 stages: coagulation, also known as “curdling”, draining and salting, and ageing (or maturing).
Coagulation occurs as a result of acidification, lactic fermentation (for fromage frais) or by the introduction of coagulating enzymes or rennet - or both. The temperature at which the operation is performed varies according to the type of cheese. Once the process is complete, a gel-like substance is obtained.
Draining consists of separating the curds from the whey. Approximately 80% of the curdled milk's water content should be extracted at this stage. Draining is influenced by two factors:
Hard cheeses, on the other hand, require much faster processing at a much higher temperature (30 to 40°C) and draining is done mechanically. The curds are cut into small cubes using a hand-held tool called a cheese harp. This creates spaces through which the whey can run off. The drained curds are then slowly and gradually mixed and heated, with the combined action of heating and stirring causing them to contract and eliminate the whey. This produces the rennet curd which is then placed in moulds. The cheese is subsequently pressed at varying degrees of pressure depending on the desired level of firmness. The entire production process is performed quickly and is complete in about 2 hours, which means that acidification does not have time to take effect and no demineralisation occurs - the resulting cheese is therefore very supple.
All different types of cheese can be produced by combining these factors to different extents:
Salting can either be performed on the curd mass, that is by applying the salt directly to the curd grains, at the cheese's surface (dry salting) or by placing the cheeses in a salt bath. This stage helps to form the rind.
With the exception of fromage frais cheeses which are packaged as soon as draining is complete, cheeses must undergo maturing, known as affinage.
The maturation time varies from one cheese to another, ranging from several weeks for a Camembert to several months for a hard cheese. Moreover, different types cheeses mature in different ways: hard cheeses only mature from the inside ,blue cheeses mature from the inside outwards and soft cheeses from the outside in.