While they start out the same, espresso beans get roasted considerably longer than standard coffee beans, reaching what's considered a dark or extra-dark roast level.
Espresso beans carry intense, complex flavor that's rich and bold, a result of high roasting temperatures. They're also oily to the touch from prolonged exposure and have deeper flavors.
Less time in a grinder equals a coarser powder that’s fit for standard coffee brews. The longer the grind, the more fine, dense, and compact the espresso powder will be.