To test for the setting point, spoon a little jam onto a chilled saucer, cool for a few seconds, then push a finger across it. If the surface wrinkles, it has reached setting point, if not, cook the jam for a further 3 minutes, then test again. Continue testing every 3 minutes until setting point is reached.
This was the first time I've ever made jam and I was told by my boyfriend (who's mum makes jam all the time) that it was the best jam he's ever tasted! I have to agree, it's delicious Mine didn't set as firm as it should have and I added a little more ginger than in the recipe. Next time, I'll put more lemon in. I also don't have a food processor, so it took me over an hour to cut up the marrow! - 17 Oct 2012