Jam, jelly and marmalade are made from fruit boiled with sugar until its setting point is reached. The essential setting agent in fruit is pectin: a naturally occurring soluble, gum-like substance present in varying amounts in the pips, skin or pith and flesh of most fruits. Pectin gels when it is heated with the natural fruit acid and added sugar. As the preserve cools down, the pectin gels enough to set the preserves, if the rations are correct. Read More . . .