- 2½ cups of finely diced rhubarb (the pieces should be about the size of a pencil eraser)
- 2 cups of chopped and crushed strawberries
- The strained juice of one small lemon
- 6½ cups sugar
- 1/2 teaspoon unsalted butter
- 1 pouch Certo Liquid Pectin (3 ounces)
In a big heavy 8-quart pot, combine the rhubarb, strawberries, lemon juice and sugar. Stir together, cover and set aside for 2-3 hours, giving it a stir once or twice.
Remove the cover and over low heat, start stirring the mixture, turning the heat up in small increments until all the sugar is dissolved. If the mixture is heated too quickly, the sugar can crystallize in the jar later. It took about 40 minutes for my mixture to fully dissolve. At this point, stir in the butter, which helps prevent air bubbles, turn the heat to almost high and stir constantly. Once the mixture comes to a full, rolling boil, quickly squeeze in the pectin, and stir for one minute. Take the pot off the heat and set a timer for 5 minutes. Each minute, stir the mixture gently to distribute the fruit throughout the jelly.
Ladle the jam into the prepared, hot, sterilized jars and process in a water bath for 10 minutes.