Ooh, a science question, my favorite kind! I'm no expert, but I found a short article on a cheese-making website that explains more about the chemistry of stretchy mozzarella cheese: The Science Behind Mozzarella: Why It Stretches. Based on this and a few other sources, there are a few things that go into giving this cheese its lovely stretch: the pH, the kneading process, and the temperature. Which is all to say that the brand and type of mozzarella cheese that you're using may play a role. The answer may be as simple as finding out where your favorite pizzeria sources their cheese from! Additionally, many folks swear by grating their own cheese rather than buying it pre-shredded, and ensuring that the cheese itself has never been frozen, which can alter the texture. One thing in this cheesemaking article did stand out, though: temperature. Commercial pizza ovens will often heat your pizza to temperatures of 800 degrees, much hotter than a home oven can reach. It's possible that the main difference between the pizzeria's cheese and your own isn't some magical chemical difference, but rather that it is simply more melted. Best of luck, and happy baking!

• Reply