The large vat filled, being stirred by Stu  and ripening Once the milk is pasteurised (or not as the case may be), we heat it to between 32 -33oC depending on what we are making and we add starter culture which determines the taste, texture and characteristics of the cheese we are making. The main microbiological purpose of the starter culture is to turn lactose, milk’s natural sugar in to lactic acid.  It is this that we measure during the cheese making process using an acid