One way to use pectin to make grape jam entails adding commercial pectin in liquid or dry form to grapes prepared for making jam. Grapes possess natural pectin, so another method includes cooking prepared grapes and sugar together to make jam.
Whether using additional commercial pectin or the natural pectin present in grapes, preparing the grapes before combining them with pectin is essential. The cook must skin and seed the grapes, finely chop the skins or blend them in a food processor. The skin contains concentrations of pectin, and cooking the skins for 10 to 15 minutes with just enough water to prevent sticking effectively extracts the pectin. A combination of pulp, the gently stewed skins and sugar cooked for 10 minutes over medium high heat yields grape jam.
When using commercial pectin to make jam, the preparation of the grapes is similar. The cook must skin the grapes, set the skins aside, simmer the pulp in water for five minutes or until soft and then press the pulp through a sieve to collect the seeds. The cook must then combine the skins, the pulp and the appropriate measurement of commercial pectin in a saucepan, and bring the mixture to a boil.
The addition of any necessary sugar typically occurs after the boil, at which point the cook stirs to dissolve the sugar and returns the mixture to a full rolling boil. Most commercial pectin products contain recipes and directions for proper use. One manufacturer, Ball, even offers a pectin calculator and recipes on FreshPreserving.com