My first batch of bramble jelly is ....

[BombasticAghast]

A bit bitter! It is sweet enough but has a slightly bitter aftertaste.

i usually make it in early September, but there are so many blackberries out that I thought I would start early.

Made blackberry mush with berries, 1/2 pint of water and juice of 2 lemons
Strained through a muslin
Added a lb of sugar for each pint of juice simmered for an hour
It set fine, but the taste isn't quite right.

Any ideas what I did wrong?

There are 5 jars and it isn't as yummy as it should be.

It's probably that the fruit itself has less sugar in it that usual - down, I guess, to the rubbish weather we've had this year.