Manufacture of cheddar cheese
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.
Coagulation can also be achieved using acids, but this method yields lower-quality cheddar.
Extracts from plants such as nettles were found to produce similar effects and have been used in some types of cheese-making (vegetable rennet).
[clarification needed] A solution using recombinant-gene (GMO microbial rennet) technology was developed and approved by the U.S. Food and Drug Administration in 1990.
Stainless steel knives are used to uniformly cut the curds at various points during the process.
Vats will vary depending on a variety of factors, but in general are in the shape of an oval or rectangle with hollow walls, called the jacket, that are used for holding warm water to keep the curds at desired temperatures.
A milling machine is used to cut the matted curds that are formed during the cheddaring process.
If the curd breaks cleanly leaving a glassy fracture, it is ready for cutting.
The curds are handled gently after cutting to prevent fat and protein loss to the whey.
The curd is prevented from sticking to the sides of the vat, but minimal agitation is desired.
Fat and protein loss may affect the ability of the cheese to be considered cheddar cheese, depending on the region where it is created (See Code of Federal Regulations for US standards) The curd is cooked by adding hot water to the jacket of the vat (up to 39 °C or 102 °F).
It is a multi-step process that reduces whey content, adjusts acidity, adds characteristic flavour, and results in a denser and sometimes crumbly texture.
[1] "Loaves" of curds are cut about 15 centimetres (6 inches) wide along each side of the vat.
When the turning process is complete, the loaves must be cut down into a size that fits in the mill.
