Fermentation and curd formation

Coagulation creates a network of proteins that holds water and fat. It can result from acidification or the action of rennet enzymes; both mechanisms often work together. Simply adding acid to hot milk, as with some fresh cheeses, is not fermentation. Draining the whey then concentrates the curd.

What do bacterial cultures do?

Starter bacteria consume lactose, the sugar in milk, and produce lactic acid. The falling pH affects how proteins behave, how whey drains and the cheese's eventual texture. This makes the course of acidification over time important, as well as the final reading at the end of production.

Why does cheese ripen?

During ripening, enzymes break proteins and fats into smaller components that can give rise to aroma compounds. These enzymes come from sources including milk, rennet and microorganisms. Additional bacterial, yeast or mould cultures help shape particular cheese varieties; not every cheese needs a long period of ripening.

Conditions matter

Salt, water content, temperature and time shape the process. It helps to distinguish cheese moisture from water activity, which describes how available that water is to microorganisms. Hygiene and controlled conditions remain necessary even when cheese contains an active culture. A strong smell alone cannot explain which changes have occurred.

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