[happy me]

Have just made my first batch of plum jam. But  I am having trouble getting it to set. Anyone got any tips please!!! Thanks

[zazen999]

It needs heating back up again and getting to the proper setting point....

[dick baker]

It needs heating back up again and getting to the proper setting point....

You have to boil it to a set point.
No specialist equipment is necessary, just bring to the boil and simmer, occasionally take a small part teaspoon and place a bit on a saucer, push the sample with your finger,if it wrinkles and solidifies slightly it is ready for the jar, if it remains fluid it aint ready, so keep simmering.
By using sugar sold as jam sugar you get the pectin necessary to get a quick set, useful if only to save you energy boiling and simmering.
I have used pectin seperately as an additive but get the best results with sugar for jam making.
The best results were with redcurrants and blackcurrants.
good luck.

[oddpaws]

Sometimes if the quantity of sugar isnt right it wont set so well and I sometimes add some lemon juisce which seems to help too.

[SMD66]

plums should have enough of their own pectin but a squirt of lemon juice could help.

Jam has to reach 104 degrees C to set, but as dick said, you don't need any equipment to test this, just a saucer.

A 'simmer' may reach that temp but more likely it will need to boil.  Be careful that the heat doesn't burn the jam tho.

[bashful_badger]

Can you re-heat unset jam once it has cooled?  I made some last week with plums and hubby turned it off before it was done because "it'd been on ages". 

All the jars etc were steam sterilised and it's been in fridge since so I think it should be ok.

[Yorkie]

I'm sure I've read Val suggest this as a strategy, but make sure you re-sterilise the jars

[MoreWhisky]

reheat and pour a bottle of Certo in.

[Val H]

A full bottle may be a bit too much