Thus, the fruit's natural flavor and color is preserved. Preservation is different though. Since no boiling or heating is done, these jams have to be stored in the refrigerator or the freezer instead of on a shelf . The secret of making a successful no-cook jam is the fruit pectin. Pectin helps the jam to set to the right consistency.
Fruit contains pectin naturally, but the amount decreases as the fruit ripens.
If a fully ripe fruit is used for making jam, you need to add pectin. Pectin will gel with a certain proportion of fruit, acid, and sugar even if the ingredients are combined when cold. It may take only a few minutes for the gel to form, or it may take two or three days. Table 1 gives a list of some of the kinds of pectin available on the market. Uncooked jams will mold or ferment if kept at room temperature.