Tried it again with Damson plum jam from the same farm, but pulled back the lemon juice to 20ml and increased the sugar syrup. My lemons were VERY tart, so with the Damson plum, it was still a bit much, as Avery notes below.. On a whim I added a bar spoon of grenadine and it actually blended nicely with the lemon, plum, and apple flavors. You probably have to enjoy grenadine to do this.