Blackberry jam dilema

I know I haven't been paying proper attention, I think I may have missed the setting point!

I've had my blackberry & apple jam bubbling away this evening for well over an hour and it's still not setting. I've been testing it regularly, honest.

I'm not very good with weights and measures - large pot of blackberries with a small proportion of apple and flung in about the same weight in sugar (normal granulated) along with a bit of water and the juice of a lemon. Should I carry on simmering or what...help

Try adding more lemon juice and re-boil.

If jam is not setting is is due to either a lack of pectin & acid, or insufficient evaporation.

If that doesn't work take it off the heat & get some commercial pectin tomorrow & try re-boiling it.

If it is overcooked (tastes of caramel) it cannot be re-boiled

Thanks SB, I'll try that. I don't think I've boiled so much that it's caramelising but it could be insufficient evaporation.

you need more sugar

A tip - when it has reached seting point take it off the heat & add a little alcohol to it (brandy, whisky, gin, vodka, whatever you like). This will help prevent mould - and tastes rather good

and helps the kids sleep (joke)

Have you used normal sugar?

I thought you needed to use jam sugar?

I'm about to embark on a plum jam trial.....

Ok, things are looking good I decided to go straight for the pectin to save messing about with more sugar and boiling etc.

Also added a bit of whisky, purely for the purpose of presevation you understand If it's not all gone by Christmas my kids can try some when they come to visit(they're both over 21), but they certainly don't need any encouragement to sleep!

Thanks for the help. If any of you lived just round the corner, I'd pop round with a jar......I've got enough