Ladling curds is NOT something that you want to do with every cheese so you need to follow your recipes. However in general, yes, as curds sit in whey the bacteria continue to "feed" on the lactose and produce lactic acid. Here are a few basic concepts:
1- After rennet, the longer you wait before cutting curds, the more moisture that the curds retain. You have control over the final "paste" by simply controlling the curd set time. Just because you have a "clean break" doesn't mean that it is time to cut curds. If you cut too early, your finished cheese will be drier and harder. So when making Parmesan for example you can create a hard, dry Parm by cutting early or a softer, slicing Parm by letting the curds sit longer before cutting. Search the forum for Flocculation and read every post about the technique.
2- The smaller the curds are cut, the more whey that is expelled. Larger curds produce cheese with more moisture. So uncut ladled curds will retain a LOT of moisture and create a softer cheese. For some cheeses, the pH at draining is critical to getting great results.
3- After cutting and cooking, the longer you wait to drain, the more acidic the curds become. Again, when you drain, you are taking away the food source for the starter bacteria. So, you have control over the final acidity and texture of the finished cheese by simply changing the timing for draining.
Cheesemaking is not about following recipes. You need to know what's going on at every step of the way and how to control the outcomes.
