Prep the tomatoes. Wash and dry them well. Core out the stem and remove any blemishes. If using juicy slicing tomatoes, consider seeding to speed up drying.

Choose your method. You can dehydrate raw slices or cooked puree. Raw keeps a fresher flavor; cooked yields a deeper, sweeter taste.

For raw slices: Slice tomatoes 1/4 inch thick. Lay them in a single layer on dehydrator trays or parchment-lined baking sheets. Avoid overlap.

For cooked puree: Roughly chop tomatoes, simmer 20–30 minutes until reduced, then blend smooth. Spread a thin, even layer (like fruit leather) onto nonstick dehydrator sheets or lined pans.

Dehydrate. Set the dehydrator to 125–135°F (52–57°C). For oven drying, set to the lowest temperature and prop the door open slightly for airflow. Dry until the pieces are brittle and snap cleanly. Slices usually take 8–12 hours; puree sheets may take 6–10 hours, depending on thickness and humidity.

Cool completely. Let the dried tomatoes come to room temperature on the trays. This prevents condensation in your grinder.

Grind to a powder. Use a spice grinder, high-speed blender, or a clean coffee grinder. Work in small batches until you get a fine, even powder.

Sift and regrind. Pass the powder through a fine mesh sieve. Return any larger bits to the grinder. This gives a smooth, consistent texture.

Optional seasoning. Stir in a small pinch of salt, a touch of citric acid, or blend with garlic/onion powder for a custom seasoning. Keep it simple so it stays versatile.

Condition the powder. For best shelf life, loosely fill a jar and let it sit 1–2 days, shaking once daily. If clumps form or moisture appears, dehydrate the powder again on a tray lined with parchment for 30–60 minutes at low heat, then cool and regrind.

Label and store. Transfer to an airtight jar, label with the date, and store properly (see below).