Sugar, or candy, thermometers are used to accurately measure the temperature and stage of a sugar solution. They’re not essential, but are useful if you’re serious about your sweets as they can read temperatures higher than 200°C.
As it boils, sugar goes through various stages, each of which is most suitable for a particular confection.
For example, thread stage is good for syrup, soft ball for fudge, hard ball for nougat or marshmallows, soft crack for chewy toffee, and, hard crack for hard toffee, brittle or spun sugar. As the solution cooks, its sugar concentration increases as the water evaporates, resulting in the different stages.
No sugar thermometer? No problem!
You don’t have to use a sugar thermometer: each stage (thread, soft ball, firm ball, hard ball, soft crack and hard crack) describes what its consistency will be when dropped into cold water.
To test whether the solution will form a syrup, allow a small amount to cool, then pull it between your thumb and forefinger – if threads form, you’ve got a good syrup.
For subsequent stages, drop a teaspoonful into cold water – the characteristics of the resulting lump determine the concentration of the syrup. A smooth lump indicates the “ball” stages with their corresponding hardness, while at “soft crack” the sugar forms pliable strands, which become brittle at “hard crack” stage.
The “thread” stage is for syrups. Use the syrup in a Italian meringue (pictured below).
The “soft ball” stage is for fudge. Try it in this buttermilk-and-bacon fudge (below)
The “hard ball stage” is for nougat or marshmallows. Try it in these homemade scorched marshmallow, but be warned: you’ll buy the store-bought variety again.
The “soft crack” stage is for chewy toffee. Try it in these salted dulce de leche toffees. Push the sugar a little further to the hard crack stage for hard toffee.