Blackcurrant Jelly help needed

I i made a pint or so of blackcurrant jelly yesterday but it has not set.....

i don't have any meths so can't test for pectin. I don't know if i have over or under boiled it, should i just go out and buy some pectin to add to it to make it set?

Help!

i simmered the blackcurrants for 25 mins and mashed them, then put into a jelly bag and hung it for 3 hours to get the juice out. I had a pint of juice and added about 3/4lb sugar as i thought 1lb wouldbe too sweet. The juice and sugar mix was boiled gently for about 15-20 mins and the scum removed.....

does that help? the unset jelly is in sterile jars, it is worth rapidly boiling for a few mins and if it still doesn't set to add pectin?

Thanks

Hope it works for you Rowan.