Home-made Blackberry Jam

In this recipe there are two alternatives for the quantity of sugar, but both work by the same method. The difference is quite simple. If equal amounts of sugar and fruit are used, more syrup is made from the sugar. Also, by using a preserving sugar containing pectin, the jam is guaranteed to set. By using half the sugar content, less syrup is made and so consequently a thicker more jammy’ texture and not quite as sweet taste is the result. I prefer to make the jam with half of the sugar co