Most fruits do not contain enough natural pectin to make jelly without added pectin. You can make your own pectin from slightly underripe apples (see recipe) or use store-bought. Although time-consuming to make, homemade pectin is worth the effort. You can freeze it or preserve it in jars, just as you would a jam or jelly, to have on hand for later use.
To make homemade pectin, you’ll need to source small, underripe fruits. If you have access to an apple tree, select undersized, cosmetically challenged apples. At farmers’ markets, apple growers may be willing to sell you large amounts of underripe fruits at a reduced price. Remember, the riper the fruit, the less pectin it will have. However, if the apples are too immature, the pectin will impart little flavor to the finished jelly. Never use apples that have been in cold storage, as they contain very little pectin.