Created by dienia b on May 10, 2015
Step 1: Wash and pit plums, do not peel.
Step 2: Thoroughly crush the plums and grapes, one layer at a time, in a saucepan with water. Bring to a boil, cover and simmer 10 minutes.
Step 3: Strain juice through a jelly bag or double layer of cheesecloth.
Step 4: Measure sugar and set aside.
Step 5: Combine 6 cups of juice with pectin in large saucepan. Bring to a hard boil over high heat, stirring constantly.
Step 6: Add the sugar and return to a full rolling boil.
Step 7: Boil hard for 1 minute, stirring constantly.
Step 8: Remove from heat, quickly skim off foam and fill hot, sterile jars, leaving inch headspace. Wipe jar rims.
Step 9: Adjust lids and process for 5 minutes in boiling water bath.
Step 10: Yield: About 10 half-pint jars