Nutrition per serving may change if servings are adjusted.
2 1/4 pounds rhubarb, trimmed and cut into 1-inch pieces (8 cups)
2 1/2 cups sugar
2 tablespoons freshly grated orange zest
2 teaspoons finely chopped crystallized ginger
Combine rhubarb, sugar and orange zest in a medium bowl. Cover with plastic wrap and refrigerate for 12 hours.
Strain liquid from the rhubarb mixture into a large heavy saucepan, pressing on the solids to release all the juice. Set the rhubarb aside. Bring the liquid to a boil and cook over medium heat until syrupy and reduced by half, 15 to 20 minutes, watching closely toward the end to prevent scorching. Add the reserved rhubarb and crystallized ginger and cook, stirring, until the rhubarb is soft and the mixture has thickened, about 5 minutes. Pour into hot, sterilized half-pint jars, leaving 1/4-inch headspace. Adjust lids and process in a boiling-water bath for 10 minutes. (Alternatively, if you do not want to process the jam in a boiling-water bath, you can simply store it in the refrigerator for up to 2 months.)