I make jam from my soft fruit, and usually have to buy out-of-season apples to grate and add for their pectin. I’d rather make totally local jam, that is, use my own apples, but I only have unripe ones at this point in the summer. Will unripe apples have enough pectin?
As it turns out, the amount of pectin is higher in underripe or unripe fruit. This guide to making jams and jellies from University of Georgia Cooperative Extension says the following:
“The amount of pectin found naturally in fruits depends upon the kind of fruit and degree of ripeness. Underripe fruits have more pectin; as fruit ripens, the pectin changes to a non-gelling form. Usually using 1⁄4 underripe fruit to 3⁄4 fully-ripe fruit makes the best product. Cooking brings out the pectin, but cooking too long destroys it.”
Here are additional resources on pectin for jam-making, from Wildflowers and Weeds. Here is an excerpt from the latter, taken from The Forager, Volume 1, Issue 3, August-September 2001, by Sam Thayer:
“To prepare liquid apple pectin, it is best to use under-ripe apples that are still a bit green, hard, and sour. Ripe apples contain less pectin, but the level varies greatly from one tree to the next; some varieties are suitable when ripe, while some have virtually no pectin by that time. Over-ripe apples are the worst. You can use your damaged or misshapen apples for making pectin. Chop them in halves or quarters, fill a large pot, and then add just enough water to almost cover the apple chunks. Cover the pot and place it on low heat for a long time, until the apples are fully cooked and you have something that looks like runny applesauce with skins and seeds in it. Stir the apples every twenty minutes or so while they are cooking.
I arrange a strainer for this ‘sauce’ by placing a cheese cloth (actually a white T-shirt) over the top of a five-gallon pail, secured by a cord tied around the rim. (A piece of cheese cloth in a colander works fine for smaller amounts.) The hot applesauce is then poured into the strainer; what drips out the bottom should be a clear, thick liquid that’s a little bit slimy to the touch. That’s your liquid apple pectin. I usually let mine strain overnight, because it drips slowly. You can get more pectin by pressing it, but then it comes out a little cloudy and carries more of the under-ripe apple flavor. I like to make a few gallons of this pectin at a time and then save it by canning or freezing – it’s not hard to get a year’s supply with one batch.”