The milk that is left over is used for making cheese; it is heated, left to curdle and then made into cheese since it is not suitable for sourmilk. This thin milk is not particularly suitable for drinking. The whey that is left after the separation of the cheese is usually left to turn to “syra”, ie. once it has cooled it is poured into a vessel or barrel and left to stand for a long time until it has become quite tough. This is usually boiled – whatever has been collected over 2 or 3 days being boiled together with any new – until it has reduced to a very small amount of the consistency of porridge. This is put into a vessel and set aside to stand very still, after which it goes hard and turns into whey-butter. NB. the blue milk can be boiled like fresh milk and does not curdle.