Translations:Cheese/30/en

Curdling

During industrial production of Emmental cheese, the as-yet-undrained curd is broken by rotating mixers.

A required step in cheesemaking is separating the milk into solid curds and liquid whey. Usually this is done by acidifying (souring) the milk and adding rennet. The acidification can be accomplished directly by the addition of an acid, such as vinegar, in a few cases (paneer, queso fresco). More commonly starter bacteria are employed instead which convert milk sugars into lactic acid. The same bacteria (and the enzymes they produce) also play a large role in the eventual flavor of aged cheeses. Most cheeses are made with starter bacteria from the Lactococcus, Lactobacillus, or Streptococcus genera. Swiss starter cultures also include Propionibacter shermani, which produces propionic acid and carbon dioxide gas bubbles during aging, giving Swiss cheese or Emmental its holes (called "eyes").