Think I bottled my jam too soon. There are blobs that look quite set but when you tip the jar it's still a bit on the runny side.
Will this mean I need to boil it up again? If I don't, will it not last as long ie if it didn't quite reach setting point does that mean it won't have quite the right preserving qualities? Or will it be fine, just a bit runny?? I have 5 jars so don't want them to go to waste.
Try the cold saucer test again, but make sure that the jam really crinkles when you test it. I use the flake test - I dip a wooden spoon in, then turn it a couple of times to get most of the jam off, then see if what's left falls off in drops or joins up to make a flake.
The jars will need to be sterilised again, which does seem like a faff, but it does need to be done.
It might not have set due to the plums being a bit ripe, so it might be worth using some pectin when you re-boil. Or you could make an extra bit of jelly to add in using brambly apples (loads of pectin).
Oh that sounds delicious. I want to make it! I'd reboil tbh, it's not too much hassle (I don't bother to resterilise jars) and better than spending the next few months apologising for runny jam and wishing you'd reboiled it.