Freezing is a great way to preserve rhubarb. And frozen rhubarb works just as well as fresh in recipes like rhubarb compote. But there are a couple of steps you need to take before you freeze it to end up with a quality product.
Giving the rhubarb stalks a quick blanching in boiling water before freezing them ensures that they will retain a good texture and their rosy color when you get around to cooking with them.
A single layer initial freeze prevents the rhubarb pieces from clumping together. The fact that they stay loose is a big advantage when, for example, you have a quart container of frozen rhubarb but only need to take out a cup of it for a recipe.
Here are the easy steps for freezing rhubarb:
Clean and Cut
If you are harvesting your own rhubarb from the garden, be sure to cut off all of the toxic leafy green parts away from the leafstalk. Only the leafstalk is edible.
Wash the rhubarb leafstalks and cut them into 1/2 to 1-inch pieces.
While you're washing and chopping the rhubarb, get a large pot of water boiling.
Blanch the Rhubarb
Have a large bowl of ice water ready.
Once the rhubarb is washed and chopped, drop the pieces into the pot of rapidly boiling water. Let them cook for 2 minutes. Drain the rhubarb in a colander. You can also steam the rhubarb for 2 minutes rather than boiling it.
Immediately transfer the blanched and drained rhubarb leafstalk pieces to the bowl of ice water. This stops the residual heat in the rhubarb from continuing to cook. Leave the rhubarb pieces in the ice water for 2 minutes. Drain well in a colander.
Single Layer Freeze
Spread the blanched and chilled rhubarb pieces in a single layer on a baking sheet. Freeze, uncovered, for 1 - 2 hours.
Transfer the frozen rhubarb to freezer bags or containers. Tightly seal, and label with the date. Frozen rhubarb will keep for 1 year. It is still safe to eat after that, but its quality will decline.
Use frozen rhubarb just as you would fresh. Because of the blanching step, the color of recipes made with frozen rhubarb will match the rosy color of the fresh leafstalks. And the tangy flavor will be just as terrific.
It is not necessary to thaw frozen rhubarb before cooking with it.