Manufacturing of cheddar cheese

The manufacture of Cheddar cheese includes the process of cheddaring, which makes this cheese unique. Cheddar cheese is named for the village of Cheddar in Somerset in South West England where it was originally made. The manufacture has since spread around the world and the name has become generic.

In general, the milk is raw milk (whole or 3.3%). The milk must be "ripened" before adding in the rennet. The term ripening means allowing the Lactic acid bacteria (LAB) to turn lactose into lactic acid, which lowers the pH of the solution, greatly aiding in the coagulation of the milk. This is vital for the production of cheese curds that are later formed into Cheddar.

Rennet is an enzyme that was traditionally collected from the stomach of a milk-fed calf (natural rennet). This enzyme is responsible for the coagulation of the milk proteins to produce curds. Cheese produced this way is neither vegetarian nor Kosher. Coagulation can also be achieved using acids, but this method yields lower-quality Cheddar. The two key components of natural rennet are chymosin and bovine pepsin. Extracts from plants such as nettles were found to produce similar effects and have been used in some types of cheese-making (vegetable rennet).

When calf-rennet grew scarce in the 1960s, scientists developed a synthesized type of Chymosin by fermenting certain bacteria or fungi (microbial rennet), but this also was not useful for all types of cheese-making. A solution using recombinant-gene (GMO microbial rennet) technology was developed and approved by the U.S. Food and Drug Administration in 1990. This splices the calf-gene for producing chymosin into the genes of certain bacteria, yeasts or fungi, producing pure chymosin.

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