[Kleftiwallah]

You don't get many jars of blackberry jelly from 5 lbs of fruit!

Cheers.  Tony.

[Felicity A]

You don't say how much water you added when you stewed your brambles down - perhaps cover fruit with water more generously next time and leave to strain overnight to get all juice out.

[Growster...]

Would a dose of Pectolase have sorted out the juicing?

I make a lot of elderberry wine, and soak the berries for thirty-six hours with a few teaspoons of the stuff, and the juice is almost like treacle sometimes!

[coldandwindy]

Pectin makes jam set. No pectin = no jam.

Pectin isn't useful for wine-making and makes wine cloudy. Adding pectolase destroys the pectin in fruit so the wine is clear.

@Kleftiwallah - you probably threw away 4 lbs of seeds. Worth it though - bramble jelly is a special treat & the seeds compost.

[Kleftiwallah]

Good morning everybody,
Felicity A, 50/50 by volume just as our recipe says.
Growster, I'm a wine maker of old and understand about pectin, but you need the pectin to set the jelly.
coldandwindy, yes the seeds are in the compost (along with damson sludge and crab apple residue).
Cheers to all,  Tony.

[Snow]

All the blackberries near me are blighted or never set. Absolute none to pick   

[Growster...]

I thought I'd got it all the wrong way round...

But you ought to see the elders juice I get from the dried packs! Add a few blackcurrants, and it's 'Eat your heart out ChateauNeuf du Pape...'