Spices should be cooled completely to room temperature before grinding to prevent moisture buildup and ensure a consistent grind.
When spices are toasted or roasted, they release their aromatic oils and enhance their flavor. However, this process also heats them up. Grinding warm spices can lead to several problems. First, the heat can cause the spices to release more oils than desired, resulting in a clumpy or pasty grind instead of a fine powder. Second, the warmth can create condensation inside the grinder, especially if the spices are even slightly moist to begin with. This moisture can lead to the spices sticking together, clogging the grinder, and potentially even promoting mold growth over time. Cooling the spices completely to room temperature ensures that they are dry and stable, allowing for a more efficient and consistent grinding process. Simply spread the toasted spices on a clean, dry surface like a baking sheet or plate and allow them to cool naturally. This usually takes about 15-30 minutes, depending on the quantity and the ambient temperature.
If you're in a hurry, you can speed up the cooling process by placing the spices in a shallow dish and putting them in the refrigerator for a few minutes. Just be sure they are completely dry before grinding.