Plum Rhubarb Jam

Combine rhubarb, plums, sugar, orange juice, water, and orange zest in a saucepan over medium heat. Gradually increase the temperature to bring the mixture to a boil, stirring occasionally until it thickens, approximately 45 minutes.

Concurrently, inspect six pint-sized jars for any signs of damage or deterioration. Discard any damaged items and proceed with the rest. Submerge the remaining jars into simmering water until they are ready to be filled.

Clean unused lids and rings in warm, soapy water before use. Prepare the jars by filling them with the hot, sterilized jam to within 1/4 inch of the top. Use a clean knife or thin spatula to remove any air bubbles that may have formed inside the jars. Wipe the rims of the jars with a damp paper towel to remove any residue.

Place hot, sterilized jars into boiling water, leaving them 2 inches apart. Pour in additional boiling water to cover the jars by at least 1 inch, ensuring they are fully submerged. Bring the mixture to a rolling boil, cover it, and process for 5 minutes.

Carefully remove the jars from the boiling water and let them rest, several inches apart, for 12 to 24 hours. Check the seals by gently pressing on the center of each lid with your finger; if it doesn't move up or down, the seal is secure. Remove the rings and store them in a cool, dark area for future use.