Throughout the cheesemaking process, pH control is critical to ensure consistent fermentation and food safety. If the pH is too low, the cheese may be prone to a brittle or pasty texture, as well as growth of mould after packaging. If the pH is too high, the cheese may become too firm, and can potentially be dangerous for consumption due to the risk of pathogen formation. The pH must be carefully monitored to detect deviations from the optimal range, which can create problems with texture, taste and public safety of cheese.
Acidification of milk begins with the addition of bacterial culture and rennet. The bacteria consume lactose and create lactic acid as a byproduct of fermentation. The lactic acid produced will cause the pH of the milk to go down. Once the milk reaches a particular pH, the rennet is added. The enzymes in rennet help to speed up curdling and create a firmer substance. For cheesemakers that dilute their rennet, the pH of the dilution water is also critical; water that is near pH 7 or higher can deactivate the rennet, causing problems with coagulation.
