Milk has been made into cheese here for thousands of years. Traces of milk-fat residue discovered by archaeologists inside earthenware pottery show that we’ve been making cheese since Neolithic times in the 4th millennium BC.
Today, approximately 40% of all milk from Northern Ireland farms which is used to make dairy products is made into cheese.
Although advances in technology have meant that some stages in the process have changed slightly over the years, the basic principles of how cheese is made have remained the same.
To make common cheeses, such as cheddar cheese, milk is firstly pasteurised (heated to a minimum of 71.7°C for at least 15 seconds) to kill any bacteria. The pasteurised milk is then cooled rapidly before being pumped into large cheese vats. Here, specially prepared, harmless bacteria, called ‘starter cultures’ are added. These ‘ripen’ the milk, and give the cheese its flavour.
Next an ingredient called ‘rennet’* is added to the milk which makes the milk separate into thick curds and runny whey. The curd is then cut into tiny particles which help release more whey.
The curds and whey are then heated and stirred to about 39°C (although this will vary based on the type of cheese being made). Most soft cheeses do not need to be stirred for as long, and most fresh cheeses will not be cooked. The stirring continues for another hour and then the whey is drained off leaving the curds (cheese). Next the curd is stacked, cut and turned to release more whey. This is called ‘cheddaring’. A little salt is added and the cheese is cut into small pieces called chips. The chips are packed into a mould and pressed. Most soft cheeses, however, are not pressed.
The cheese is then taken out of the mould, wrapped and stored. The longer a cheese is stored, the stronger its flavour will be. Soft cheeses can be ripened or fresh. Fresh cheeses (such as cottage cheese) are not matured and are ready for consumption as soon as the process has been completed. Ripened cheeses (such as Brie) are left in rooms with controlled temperatures and humidity.
Examples of hard cheese: Cheddar (mature, mild, reduced–fat etc)
Examples of soft cheese: Cottage cheese, cream cheese, and Brie–type cheeses.
In NI, our favourite cheese is the traditional Cheddar but contemporary flavour variations and speciality blue-vein and soft cheese varieties are becoming increasingly popular. To find out about our cheese culture and heritage in Northern Ireland click here. There’s more on the nutrients in cheese in the dairy nutrition section.
* The majority of rennet used for cheese–making in the UK is from non–animal sources which makes the cheese suitable for vegetarians.