Rhubarb is so well known for being the star ingredient in rhubarb pie that it is also known as the “pie fruit.” The other popular culinary use that rhubarb is known for is rhubarb jelly. This flavor is not as popular as more mainstream flavors like grape or strawberry jellies, and it can be hard to find in a regular grocery store. Most fans of rhubarb jelly make their own at home, with recipes available online and in cookbooks. Classic variations on the standard rhubarb jelly include rhubarb-strawberry and rhubarb-mint jelly, but there are also more exotic possibilities because rhubarb pairs well with flavors like ginger, lemon, rosemary, and balsamic vinegar.
Botanically, rhubarb is classified as a vegetable. Due to its tart and acidic nature, most culinary applications combine rhubarb with large amounts of sugar. The overall sweetness of rhubarb recipes is why it commonly referred to as a fruit. Rhubarb jelly recipes typically call for an equal ratio of rhubarb to sugar.
The use of rhubarb for jelly and other recipes has become a part of the popular interest in eating fresh and local foods. Rhubarb begins to appear in farmers’ markets in the spring, and is in season from April to September. Fresh rhubarb stalks should be firm and crisp, not limp or bendable. When cooking with fresh rhubarb, it is extremely important to use only the stalks and not the leaves of the plant. The leaves contain high levels of oxalic acid that causes a toxic reaction when consumed and can be fatal in sufficient quantities.
There are several different varieties of rhubarb, all of which are suitable for making jelly. Field-grown rhubarb has pale red stalks. There is also a variety with green stalks, which is harder to find but is preferred by some cooks. Hothouse-grown rhubarb has darker, deeper red stalks. Frozen rhubarb is a convenient substitute when fresh rhubarb isn’t available, and can be found in some stores year-round.
Most recipes for jelly involve stewing the rhubarb by combining the fruit with sugar and water over low heat. Rhubarb can also be prepared by maceration, which is allowing it to soak in the sugar and water mixture for longer periods of time without heat. While home canning is a very popular method of preserving jelly, it does require specialized equipment and careful preparation to ensure food safety. There are also refrigerator recipes for rhubarb jelly that allow the jelly to be stored in the refrigerator for shorter periods of time.