You can grind species with a coffee grinder, but we don't recommend it. If you're using a burr grinder, you won't get the fine powder texture that's best when cooking with spices–the exception being a Turkish grinder. However, the main reason is that grinding spices in your coffee grinder will leave unwanted flavors and aromas. Some spices such as star anise or cardamom pods might also damage the burrs. Spice grinding is the one instance where we wholeheartedly recommend a blade grinder!