I tried making the plum jam yesterday for the first time. After removing the stones, I had 920g of plum, added a whole lemon, the spices and pureed that altogether as book says on speed 9. Then I added 600g sugar (the recipe says 600-800) and pureed that together. Then I started cooking it all but after 5 minutes remembered that I had planned on adding some pectin powder so added 2 tsp of that in and put it to a higher speed just for 2 seconds to mix it all through. Then continued cooking for another 50 minutes (recipe says 40-60min) but it wasn't set. So I cooked on varoma for another 3 min as recipe suggested and it still wasn't set. I thought perhaps it would thicken upon cooling but it hasn't.
Any ideas on where exactly I went wrong? I'm thinking obviously I should have added the pectin in at the beginning but it shouldn't have made that much of a difference.
Something I read said you shouldn't boil the jam with pectin in it too long or it stops working???
Another thing said I could tip it all back in the pot and boil it again with more pectin/sugar/lemon juice for a minute and it should set?
I don't so much care about this batch since it was an experiment but I want to know for next time where I went wrong? Should I add the pectin in at the very end perhaps?
Sorry this is really long :-)