Morning reg, I agree, basically a cheese needs to reach a certain pH to ensure a process is complete, before proceeding to the next step. How it gets there is not just a function of ingredients, process, and time as per the home Cheese Making Recipes we all use, but also the more subtle type and season of milk; quality, stength, and freshness of cultures; humidity and temperature. Much of which we ignore in our simple recipes.
Welcome to the world of intermediate vs beginner cheese making
.