Rhubarb powder is made from pieces of rhubarb that have been dehydrated and then ground finely.
You can use it as an ingredient in rubs or spice mixtures, or as you would a flavouring powder in baked goods, etc. It adds tart notes.
See also: Drying rhubarb
Yields and Equivalents
1.75 kg (4 lbs) rhubarb as purchased (no leaves, but untrimmed) = 1.5 kg (3.3 lbs) rhubarb, fresh, trimmed = 12 cup fresh, trimmed & chopped into 2 cm (1 inch) pieces = 2 3/4 cups dried pieces = 120 g (4 oz) dried pieces = 20 tablespoons powder
5 tablespoons rhubarb powder = approx. 30 g (1 oz)
See drying rhubarb for directions for the initial drying. Dry a bit longer to ensure the pieces are crisp.
You may wish to cut the rhubarb 50% smaller than the drying rhubarb directions call for, to ensure more even and thorough drying.
Dry the rhubarb past the leathery stage; dry it until it is crisp.
When dried and cooled, store dried rhubarb pieces for a few days in a sealed container to ensure there will be no condensation starting. If there is, dehydrate a bit more, as that excess moisture would affect your powder.
When are you sure that your rhubarb pieces are safely dried, you can grind them into powder. If the pieces are not crisp, you won’t be able to powder them down: you’ll need to return them to the dehydrator for another hour or two.
It’s ideal if you can grind in two steps:
- Put rhubarb pieces in food processor and grind to a coarse powder;
- Take that coarse powder, and in small batches, process through an electric coffee bean mill to reduce to a fine powder.
The reason is that the food processor won’t get it to a fine powder, yet, the larger pieces can be too large for the electric mill to handle. You may devise another one-step phase to get it to a fine powder. (It will never get to the fine consistency of a fine-wheaten flour.)
Store in an air-tight jar. Label jar with name of product and date. Store away from heat and direct light.
No need to rehydrate first when using.
Add rhubarb powder to spice mixes, dry rub mixes, to baking, etc.
Add about a teaspoon of rhubarb powder to 1 cup (250 ml / 8 oz) of vegetable juice or smoothie for a zap of tartness, or stir into yoghurt.
Give your cocktails some pucker power by rimming the edges of cocktail glasses with rhubarb powder.