Combine the sugar, salt, espresso beans, pepper, garlic powder, cinnamon, cumin, and cayenne in a resealable container, cover tightly, and shake well to combine. Store in a cool, dry place.
Notes
Storage--Store the rub in an airtight container at room temperature for up to 2 months or freeze for up to 6 months.
Scaling--The BBQ dry rub recipe can be scaled up or down easily, depending on how frequently you use it.
Breaking it up--If the rub begins to harden or clump during storage, toss it into a food processor and give it a quick blitz.