Freezing rhubarb is an excellent way of preserving this fruit, but doing so requires forethought, as rhubarb stalks can take up a lot of room in a freezer if not prepared properly. When planning to freeze rhubarb, it is a good idea to decide beforehand how the rhubarb will be used, as this determines the most sensible preparation, storage, and packing methods. To ensure the tastiest, safest rhubarb, it is important to prep the rhubarb by cutting, washing, and pre-cooking it to preserve its flavor. If someone knows in advance the types of recipes into which the rhubarb will be added, storing it in syrup or freezing individual pieces of rhubarb can help a cook save time when actually cooking with rhubarb.
When preparing rhubarb for freezing, it is important to remove its leaves entirely and dispose of them safely, as they can be toxic. The stalks should be inspected for damage prior to thorough washing. The rhubarb should be cut up into small pieces measuring 1 to 2 inches in length. To preserve their freshness, the rhubarb pieces can be added to boiling water for about a minute and then fished out and immediately run under cold water. After this process, sometimes called blanching, the rhubarb can be packed into containers, labeled with the current date, and placed in a freezer that is ideally 0 degrees Fahrenheit (about -18 degrees Celsius). Rhubarb can be safely frozen for up to one year.
The choice of containers for freezing rhubarb should be based on whether the rhubarb is to be frozen on its own or in some type of liquid. If the person preparing the rhubarb is simply going to dice the rhubarb and store it on its own, high-quality freezer bags should work fine. On the other hand, if the rhubarb is cooked and stored in a syrup, a rigid, sealed plastic container is the best and safest choice for freezing rhubarb.
If someone has a lot of rhubarb to work with, he may decide to freeze the rhubarb in several different ways, each suited to a different style of preparation. For example, if a cook who is freezing rhubarb knows that he will be using small amounts of rhubarb at a time, he may want to freeze pieces of rhubarb individually by spreading them out on a cookie sheet or large pan and placing them in the freezer for several hours and then packing them into freezer bags. Since the pieces are not frozen together, he can remove as much as he wants each time he needs to use the rhubarb. Another option is to pack the rhubarb in a sugar syrup, which can reduce preparation time if it is to be added to pies and crumbles. The syrup can be made by mixing 3 cups of sugar with 4 cups of water, which should then be boiled, cooled, and poured over chopped rhubarb that has already been packed into freezer-safe containers.