Heat a heavy bottom pan on medium heat on the stove for 2 minutes. Add the coriander seeds and dry roast the seeds, stirring continuously, for about 5 minutes, or until they become fragrant and slightly darker in color.
Turn off the heat and transfer the coriander seeds to a plate to stop the cooking process. Let it cool completely for about 20-30 minutes.
Add cooled roasted coriander seeds to a coffee or spice grinder in batches. Pulse a few times, shaking the blender to prevent the powder from clumping. If needed, scrape the sides once in between.
Continue to pulse until finely ground. Store in an airtight container in a cool dry place for up to 6 months.
Notes
Quick sorting: Spread the coriander seeds in a large platter and using your fingers, look for small stones or dirt.
Roast on medium heat: Coriander seeds contain oils that can cause it to burn quickly. Roasting on medium heat prevents the seeds from burning.
Even cooking: Stir continuously to ensure even roasting of seeds.
Cool completely: Always let the roasted coriander cool completely before grinding them. If ground prior to cooling, the steam and warm essential oils will cause the mixture to become gummy.
Prolong shelf life: Store in a cool dark cabinet or drawer, away from stoves and other heat sources. This makes them last longer. Whole coriander seeds can also be stored in the freezer.
Note: The nutrition facts below are my estimates based on 1 teaspoon of coriander seeds. If you are following any diet plan, I recommend cross-checking with your preferred nutrition calculator.