When you boil sugar, it needs to be monitored carefully to remove any impurities and keep the sugar crystals from sticking to the pan. The longer you boil the sugar, the higher the temperature will rise. There are different stages of boiling temperatures for sugar, and each stage is used for different recipes. A candy thermometer will help you to determine the appropriate temperature you need for the recipe to ensure you boil the sugar and water for the appropriate amount of time.
Pour 1 cup of granulated sugar and 1/2 cup of water into a saucepan.
Stir the sugar until it dissolves into the water. Heat the water gently over low heat until the sugar fully dissolves.
Bring the sugar and water mixture to a full boil on the hob. Remove the foam from the top of the mixture with a ladle and place it into a bowl to discard.
Dip a pastry brush in water. Wipe the brush along the sides of the sauce pan to wash down the sugar crystals that stick to the side of the sauce pan.
Keep removing the foam and washing down the sugar until the mixture appears clear.
Boil the sugar until it reaches the desired temperature on a candy thermometer for the recipe. Different stages are used for different recipes. For instance, a thread stage is often used in syrups and jellies, while a softball stage is used in meringue and creams. See "Resources" for different temperature guides.
Remove the sauce pan from the hob. Place it on a damp cloth so that it does not reach a higher temperature.
Avoid stirring the boiling sugar water unless the recipe suggests otherwise.