|Pectin, a bio polymer|
of (among other constituents) D-galacturonic acid,
shown here in a powder form.
But, you must know, I sing the praise of pectin as a thickening agent for jams and jellies! aaaaaAAAAhhhh! did you hear the angels sing, or, was that just me?
Pectin is now readily available at the grocers in it's modern tech rendered form as a dry powder. It was only available in it's liquid form for jam and jelly making when I was a kid, but we made our own or only made jellies that were high in pectin and therefore thickened on it's own.
When making your own pectin, you can use a citrus fruit like oranges or lemons which will render a lot of pectin as it contains about 30% in the peels. But, and there is a good one to know here, BUT, oranges and lemons have a distinct flavor that should be taken into account, it could change the flavor of your jam. An orange pectin would blend well in pineapple or orange marmalade. Apples contain a lot less pectin, by volume (1.5%) but, the flavor is easily blended into stronger fruits, so you will have a true grape flavor in the jam, not a lemon-grape.
After all the trouble of making your own pectin, jar it. Seal it in a sterilized jar (simmering temp or 185 degrees for 15 minutes)and date it. Pectin will keep jarred for about four months.
To use the pectin, 2/3 cup liquid pectin equals one packet of distilled dry pectin. Write that down inside your cookbook in the margins of the jelly making recipes. Even if you never forget, the next generation needs to know what you know, Make a note, then make jam!