Tried this yesterday. Used approx 620g combined rhubarb and apple with 500g jam sugar and juice of 1 medium lemon. Great hit with the family. I'd prefer the tangier version originally posted I think as I like the tartness of rhubarb, however, no-one else eats rhubarb in this household - but they love the jam! Great for when I have too much rhubarb growing. I also added a drop of cochineal to pink it up a bit as my rhubarb is quite green even though the stems look pink! Thanks again for the recipe x