Prepare the Peels: Arrange tomato skins in a single layer on dehydrator trays lined with parchment paper or mesh liner. A little overlapping is okay, but don't stack.

Dehydrate: Set dehydrator to 115°F and dry for about 12 hours. Skins are done when completely brittle with no flexibility.

Cool: Remove skins and let cool completely to room temperature before grinding to prevent condensation.

Grind: Working in small batches, grind the dried skins into a fine powder with no visible pieces remaining.

Store: Keep in a tightly sealed jar. Will stay fresh for 1 year with regular storage or up to 10 years if vacuum sealed. In humid climates, use smaller containers to limit exposure.