Shredding cheese is easier with a chilled block because the cold temperature makes the cheese firmer, preventing it from sticking to the grater and clumping together. This results in cleaner, more uniform shreds.
When cheese is at room temperature, its fats soften and become sticky. This stickiness causes the cheese to adhere to the grater, making it difficult to shred and often resulting in a messy, clumpy pile. Chilling the cheese, ideally for about 30 minutes in the refrigerator before shredding, hardens the fats. This hardening allows the cheese to maintain its shape as it's grated, producing distinct, separate shreds. The cold temperature also reduces friction between the cheese and the grater, further preventing sticking. Different types of cheese will react differently to chilling. Softer cheeses like mozzarella may still be a bit sticky even when chilled, while harder cheeses like Parmesan will shred very easily.
For even easier shredding, lightly coat your grater with cooking spray before grating the chilled cheese. This creates a non-stick surface that further reduces friction and prevents the cheese from sticking.