Sugar

Preserving sugar dissolves quickly and is ideal for jam-making, but it is expensive and not always easy to obtain. Cube or granulated sugar is perfectly satisfactory. Sugar must be stirred carefully into the cooked fruit until dissolved before hard boiling, or crystals will remain and burn on the bottom of the pan, and will also affect the smoothness of the jam. Sugar may be warmed slightly before adding to the fruit to speed up the dissolving process.