Work out sugar syrup stage temperature instantly with clear inputs, formula shown and shareable results.
Sugar syrup stages correspond to sugar concentration, and temperature is simply a convenient proxy: the boiling point rises as water evaporates. Because water boils about 1 degree lower per 300 metres of altitude, every stage temperature must be reduced by the same amount or the syrup will be over-concentrated.
Altitude correction
Target temperature = sea-level stage temperature - altitude (m) / 300
Water to evaporate
Water removed = initial mass - sugar x 100 / target concentration %
Boiling sugar reaches temperatures far above water's boiling point and causes severe burns that are worsened by its adherence to skin. Use appropriate protection and never add water to hot syrup.
Boil plain water and read the thermometer; the reading is your local boiling point. Subtract 100 minus that reading from every published stage temperature.
They determine the finished texture: soft ball gives fudge and fondant, firm ball caramels, hard ball nougat and marshmallow, hard crack brittles and pulled sugar.