No it won't set unless you add gelatin, Pomona pectin, or a similar thickening agent. Low sugar preserves are always softer set even with other additives, are more prone to molds and fungus, and do not store as long.

If you choose to use gelatin then do not process them, just fridge storage. Jams/jellies/preserves is the one place where the sugar plays vital role in both quality and safety.

Dave

Thank you Dave. I have a batch macerating in the fridge now that I made with the full 4 cups sugar. I don't like really sweet stuff so I don't know if I will like these preserves or not. The peaches were perfect before adding any sugar!

I agree, they won't set well if you reduce the sugar much further, the old formula was equal amounts of sugar to fruit, although I've successfully reduced that by nearly half, which would make the 6:6 ratio (equal amounts) closer to the 6:4 ratio that Melly's recipe calls for.

Go much lower than that ratio and you can get a fruit spread that thickens, more like a fruit butter than a jam or jelly. It's thick and it's not as sweet, and it's totally acceptable to me, but not the texture of preserves or jam. As Dave mentioned, it doesn't store as well as the full sugar versions, and will lose quality even if it doesn't spoil.

Annie

Annie,

Thanks for your input! I think with some fruits, too much sugar hides the wonderful complex taste of the fruit. I don't put up a lot of fruit preserves, jams, jellies etc. for that reason. I find the end product too sweet for my liking, and reducing the sugar isn't usually possible if I want the product to set. I admit it is still confusing finding that balance - the right ratios of sugar, pectin, acid, fruit, but thank goodness for tested recipes! :). I freeze a lot of fruit rather than canning it, so I can control the sugar when baking or cooking with it. The draw back is the freezer space needed and the risk of loss due to reliance on the freezer and electricity.

However, since I prefer a soft set over traditional jam/jelly texture, I should make some small batches where I reduce the sugar to a level I like and just be happy with however much I can get it to thicken! I would have to make a note to make sure it gets eaten up fairly quickly though, since I would hate to lose it from spoilage or poor quality. I can keep making full sugar recipes for my family and friends. They have no complaints about full sugar recipes!