There are a few different ways to adjust the grind on the Rancilio Rocky, but for espresso, you'll want to start with a fairly fine grind. From there, you can experiment with coarser or finer grinds until you find the perfect setting for your taste. Once you've found the right grind, be sure to keep an eye on it and make adjustments as needed - especially if you notice any changes in the quality of your espresso shots.