Last year I was given some plums and I made some jam from a recipe that I got from the wife’s cook book and it was great this year I hade a load of cherries which turned out all wrong they wouldn’t set, I put this down to me doing something wrong, then I was given a large bag of damsons, this time I followed the instructions to the letter but made two batches, the recipe said 3 pounds of fruit 3 pounds of sugar ¾ Pt water boil fruit in water and simmer for 10 to 15 minuets till soft, add sugar bring back to boil, for 10 to 15 minuets , which I did every time but on the second batch I added some pectin but it made no defiance nether batch would set, what am I doing wrong, help please capt nemo rtd