Making cheese is not difficult as long as attention is paid to the quality and handling of the milk, hygienic procedures are followed and the appropriate equipment is used. It is appropriate to look at what processes are involved and what equipment is needed. If milk is left it will ripen and eventually turn sour. This is because bacteria act on the milk sugar lactose, producing lactic acid. This, in turn, brings about a separation of the milk into solid curds and liquid whey. It is the curds that eventually form cheese. The problem with producing cheese in this way is twofold:
- An extended period of natural souring encourages the growth of unsuitable, possibly harmful bacteria.
- The milk may have become too acidic for the particular cheese recipe.
The safest way of producing cheese is to first pasteurise the milk by heating it to 66 OC for half an hour, so that any unwelcome bacteria are removed. Then, the milk is cooled and a culture of appropriate bacteria (a lacto-bacilli starter) is added so that the milk is ripened without needing an extended period to do so. Finally, rennet is added. This acts on the casein of the milk, making it coagulate and form curds and whey.
Traditionally, the evening’s milking was set aside to ripen and then mixed with the morning’s milking, so that it provided a natural starter. Many people still use this method and there is nothing wrong with it as long as the quality of milk in its production and handling are second to none. If there is any doubt about the quality of the milk, it should be pasteurised before use.
