Sugar syrups are solutions of sugar dissolved in water, which vary in their concentration of sugar to water. Lighter syrups are used for poaching fruits while heavy sugar syrups, made with more sugar, are used to make confectionery and caramels.
For the home cook, a sugar thermometer is helpful in determining the exact temperature and stages of the boiled syrup. To make a sugar syrup, put the sugar and water into a saucepan and dissolve the sugar over low heat. Wash down the side of the pan with a wet brush to dissolve any crystals. To make the syrup stronger, bring the mixture to the boil and keep boiling until you reach the following stages (the recipe will specify which stage you need to reach):