Here is an answer from a novice. You can buy pectin designed for low sugar jam. I haven't tried it but would recommend that you do rather than just reducing sugar. My plums tend to be tart and I have used the full sugar amount. It IS a LOT of sugar.

Here's what I do...
I cut up plums, as many as I have...
Cook them until they are mushy and the juices flow...about 20 to 30 minutes depending on how much plums you have.
Measure the cooked fruit and add an aqual quantity of sugar, put back into the pot and cook until "jammy". If you want a firm jell you will have to cook it maybe an hour or more ..if you want it sort of soupy...20 to 30 minutes should be enough...pour while very very hot into jars just taken out of boiling water where they have been boiling and pour into the jars and top with parrafin.

Hints....stir very often while cooking so it doesn't scorch...some cinnamon is good...but don't use cinnamon stick unless you remove it as that may make it mold. cinnamon and cloves are good...grated lamon zest is good too.
Easy? you betcha!
Linda C

Less ripe plums will set firmer than ripe or over-ripe plums. That's, of course, if you don't mind a more tangy jam.

Jams that don't use commercial pectin (I'm speaking of regular pectin, not the low-sugar variety) don't require as much sugar. Making jam as LindaC suggested will use less sugar.

In a traditional preserve you need a balance of fruit, sugar and acid. Sometimes increasing the acid (i.e. lemon juice) will create more problems than it solves.

Another option is Pomona Pectin, which allows you to use as much or as little sugar as you like, even no sugar whatsoever.

Carol

Here is a link that might be useful: Pomona's Pectin

Eileen, I have greatly reduced the amount of sugar in long cooked jams without commercial pectin, and have had some success.

My latest venture was 12 cups of strawberries (which called for an equal amount of sugar) and reduced the sugar to 4 cups. I got a decent preserve, although it's rather a soft set.

I've done the same with peaches, and ended up cooking them long enough that they become more like a fruit butter than a jam, but they are much lower in sugar, higher in fruit although they are more "thick" than "jelled".

I'm planning to try plum jam tonight with a reduced amount of sugar. I'll let you know how it goes, as I'm still in the "experimenting" stage with low sugar/all fruit spreads.

Annie

Thanks!

Linda, I canned 'cots last year and made a lot of peach and nectarine butters but this is my first try at jam. I'm concerned about the jelling factor since I've never tried it. I do like the idea of adding some spice and zest, though. I have some cardamon that might be nice to add. I'll crush the seeds in a mortar and pestle.

Denise and Carol, I found that pectin at my local health food store. $3-something a box. I'll pick some up later.

Annie, I'll look forward to hearing about your low-sugar plum jam efforts. My plums are really quite sweet and ripe. Perhaps I should stick with plum butter. I'll have to see how ripe they are when I pick. I'm planning to pick tomorrow early morning and make a day of canning.

I'm also in the 'less is better' camp. I just tell people who are recipients to consume the jar within a few weeks as it WILL mold otherwise.

Low sugar pectin still requires a lot of sugar, IMHO. I have experimented with low sugar jams because I like them better. They are a little runnier, but fine IMHO. There's also plum butter. You can also add a finely chopped/shredded apple to the fruit mix, which has natural pectin. I can my low sugar jams in those tiny jars, 1/4 pint, so they aren't as likely to go bad on me. Being single and watching my sweets, i just don't use up jam that fast! I gave my friend a jar of my peach maple jam in a 1/2 pint, and she said her family ate it up in one day. It would take me weeks to do that.

I agree, sugar is a preservative and so low or no sugar spreads will spoil far more quickly than the regular redcipes with a lot of sugar.

I put all of mine into the half pint jars, just one cup of jam. That way, even if I don't finish it all, not so much is lost.

I do that because I have a bunch of that size and don't want to buy new jars!

Annie

Barnmom,
I made two batches of Santa Rosa Plum jam in the past 10 days. The first batch, I used about 4 lbs very ripe Santa Rosa plums, 2 lbs sugar (Trader Joes organic evaporated cane juice), fresh juice from 2 lemons and 1 pkg. sure-jell.

I first cut the plums in half, simmered them until the pits fell out, removed the pits, added the sugar and lemon and pectin, and cooked on high heat, stirring for about 20 minutes. It jelled beautifully. The taste is wonderful, but everyone in the family thinks it's more tart than eating the fruit by itself.

The second batch, I used the method from "Mes Confitures". I again used about 6 lbs very ripe Santa Rosa plums, but more sugar, about 4 lbs (also Trader Joes organic evaporated cane juice), fresh juice from 2 lemons and no pectin. This time I added 3 vanilla beans, split open.

I first cut the plums in half but combined them with the sugar, vanlla and lemon right away. I let the mixture sit for an hour, then simmered for about 10 minutes. Then I put the mixture into the fridge overnight. The next day, I removed the large pieces of plums that didn't contain the pits, and cooked the rest on high heat, stirring for about 30 minutes (until it started to set... much longer than the recipe stated). I removed the pits after they all separated out, and also the vanilla beans. I then added back the plum pieces, brought back to a high boil for a few minutes. Again, the mixture jelled beautifully. The taste is wonderful, but everyone in the family thinks the tartness is about the same!

I do however notice that I very much prefer the taste of the second jam. The first seems much closer to commercial jams. Definitely a wonderful "plum-ness" with such fresh ripe fruit, but a blended sweet/tart.

The second method seems "brighter" to me somehow. Each of the flavors, tart, sweet, plum-ness, vanilla, lemon seem separated and concentrated. Hard to describe. But it's now my favorite method by far.

Good luck with your jam experiments. It's great to see so many jam threads. I'm very inspired this year.

I'm excited to get started this evening when it cools down a little. We are expecting another 110ð day here. I'll report back when I have a sense of how it's going. Love the recipes! I read some good advice about simmering a long time: set your pot in a cast iron skillet to keep the scorch potential down. I'm going to do that this time.