Sixteen kilos of tomatoes make about a kilo of powder. It replaces paste, thickens sauce and seasons everything, and you can make it from the skins you would have thrown away.
Whole tomatoes or saved skins
Both work. Whole tomatoes give a rounder, sweeter powder. Skins alone give a more intense, slightly bitter one that is excellent in stock and rubs and costs you nothing, since they are what is left after passata.
If you are peeling tomatoes anyway, freeze the skins as you go and dry a big batch at the end of the season.
Dry to brittle, not leathery
This is the step people get wrong. Leathery tomato will not grind, it will smear and clog the mill, and any moisture left behind turns the powder into a solid block in the jar within a fortnight.
Dry at 57 C until pieces snap cleanly and there is no flex at all. Then let them cool completely before grinding, because warm pieces release steam into the grinder.
Yield
| Input | Approximate output |
|---|---|
| 1 kg whole tomatoes | ~60 g powder |
| 5 kg whole tomatoes | ~300 g, a jam jar |
| 16 kg whole tomatoes | ~1 kg |
| Skins from 5 kg | ~30 to 40 g |
Grinding
A spice or coffee grinder in short bursts, or a blender jug if you have a lot. Sieve after grinding and put the coarse bits back through. A fine powder keeps better than a gritty one because there is less surface trapping moisture.
Grind in small batches. A full grinder heats up and the powder cakes on the walls.
Stopping it clumping
Three things: dry fully, cool fully, and seal into a small jar with a desiccant sachet or a bay leaf, kept out of the kitchen steam. Do not store it above the hob.
If it does set solid, it is not ruined. Break it up, spread it back on a tray for an hour at 50 C, cool and re-grind.
Using it
One part powder to one part water makes a paste. Two to three parts water makes a passata. A spoonful thickens and deepens any sauce, soup or stew, and it goes into dry rubs, bread dough and popcorn seasoning.
Other powders worth making the same way: mushroom, onion, celery leaf, roast pepper, courgette and spinach. Mushroom powder is the one people become attached to.
Questions people ask
How many tomatoes for a jar? Around 5 kg for a standard jam jar.
Does it clump? Only if it was not fully dry or is stored somewhere humid.
Can you use peels and trimmings? Yes, and they make the more intense powder of the two.
Safety note. Dried tomato and tomato powder are shelf stable when fully dry. Discard any jar that cakes hard and smells sour or musty, since that means moisture got in.
What this is based on
- National Center for Home Food Preservation, drying vegetables
- University extension publications on drying tomatoes
- Published food composition data for tomato water content