Boiling Syrups for Sugar Work

, we discussed the boiling of sugar syrups for use in various desserts. When syrups are boiled until nearly all the water is evaporated, the sugar becomes solid when it cools. This process enables us to make decorative pieces out of sugar that is boiled to 300°F(149°C) or more and shaped while still hot.

As you learned,sugar that is boiled in a syrup containing an acid undergoes a chemical change called inversion, in which a molecule of double sugar (sucrose) combines with a molecule of water and changes into two molecules of simple sugar (dextrose and levulose). Invert sugar, you remember, resists crystallization, and plain sucrose (granulated sugar) crystallizes easily. The amount of sugar that is inverted depends on the amount of acid present. This principle is used in the production of fondant icing: Just enough cream of tartar or glucose is added to the syrup to create a mass of extremely fine sugar crystals that give fondant its pure white color.