Sweets are prepared by dissolving sugar in water or milk to form a syrup, and boiling it until it starts to caramelize. Depending on the solvent and the end result of the process, the product may be called sweets, caramel, toffee, fudge, etc. The recipe used also predicts how hard, soft, chewy or brittle the end result should be.

The eventual texture of sweets depends on the temperature to which the sugar solution is boiled, since the presence of a solute in a liquid tends to elevate the boiling point of the liquid. Increasing the sugar content will also raise the boiling point. As the syrup is heated, it boils, which causes the sugar concentration in the syrup to increase due to evaporation of the water, which raises the boiling point even further. In general, higher temperatures — which imply greater sugar concentrations — result in hard, brittle sweets, and lower temperatures result in softer sweets.