So this morning I made some blackberry jam (just blackberries, lemon juice and sugar). But apparently I overcooked it, because after dropping it in the pot and sealing it, it cooled off and now it's rock-solid.

Is there anything I can do to save it? I was thinking about trying to scoop it out and re-cook it and see if it'd soften up, but considering how much work it'll be to get it out, I'd rather be sure it'd actually work.

If not, is there anything else I can use it for?

3 Answers 3


From the description "Rock-solid" you guess correctly that you have overcooked your jam mixture. The process of overcooking your jam mixture results in most of the water content evaporating. In candy terms, your jam is probably somewhere between Hard-Ball stage to Caramelized stage.

For jelly/jam you want the temperature around 220 degree F. Hard ball stage is about 250 degree F. Depending on how far your "jam" is into these stages you may be able to save your "jam" by introducing more water back into it. Try and out a small portion of it into a sauce pan and adding a little bit of water to it. If you are able to turn that mixture into something resembling jam by adding water, that means you haven't cooked it beyond saving and you can do that to the rest of your jam. Note that fruit flavors are volatile so cooking further will result in the blackberry flavors deteriorating.

Otherwise treat your jam mixture as a candy.

  • This worked! I added some more water, recooked, and then mixed it through a bit of a new batch and it seems to be just fine now. Thanks.
    – Erik
    Aug 10, 2015 at 14:07
  • @Erik, I'm glad everything worked out for you. :)
    – Jay
    Aug 10, 2015 at 16:01

You just made hard candy. Chisel some off and see how it tastes.


If the Jam or Syrup is simply crystalizing, then you simply have a too high sugar:water ratio; the sugar is dissolved at 100 C but oversaturates and so crashes out of solution when it cools to room temperature. If this is the case, then heat your jar in boiling water to soften it, then pour it into a pan and reboil it, adding a little extra water. Then when it cools it will simply be a thick syrup, and shouldn't crystalise (Think how honey crystalises). Careful, if you cool it in your fridge it may still crystalize.

If your jam is using gelatine or pectin then this may not work at all, though you should be able to get a syrup at the very least.

Tip: If you know the amount of sugar in your Jam and the weight of fruit, by measuring the weight of your solution you can test at 100 C if it will oversaturate: The maximum solubility of sugar in water at Room Temperature is 2 grams per mililitre of water. 1 ml of water = 1 gram so your solution should weigh just over 1.5 times the mass of sugar you used. Aim to be below this but as close as possible to it (maybe 1.8).

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