Method:
Measure prepared fruit into heavy saucepan. Add Certo crystals and stir well. Place over high heat, stir until mixture comes to a full boil. Stir in sugar. Continue to stir over high heat until mixture comes to a full rolling boil. Boil hard for 1 minute, stirring constantly. Use the “sheeting-off test” and cool a small amount to room temperature to determine when the jam stage is reached. (Continue boiling if needed). Remove from heat. Stir and skim foam for 5 minutes to prevent floating fruit. Pour into sterilized jars and seal.

Spoon or Sheet Test

Dip a cool metal spoon into the boiling jelly mixture and lift the spoon out of the steam so the syrup runs off the side. When the mixture first starts to boil, the drops will be light and syrupy. As the syrup continues to boil, the drops will become heavier and will drop off the spoon two at a time. When the two drops form together and "sheet" off the spoon, the jellying point has been reached.