Sugar concentration

Sugar concentration tells how much of a solution is sugar. In cooking it is commonly stated as percent, and in fruit and syrup work as degrees Brix: one degree Brix corresponds to one gram of sucrose dissolved in 100 grams of solution. It is read with a refractometer, an optical instrument that measures how light refracts as it passes through a sample.

Candy making follows concentration by temperature. The Exploratorium lists the thread stage at about 80 percent sugar, the soft-ball stage at 85, the firm-ball stage at 87, the hard-ball stage at 92, the soft-crack stage at 95 and the hard-crack stage at 99, with the clear-liquid stage at 100 percent.

As a sugar syrup is cooked, water boils away, the sugar concentration increases, and the temperature rises.