The last few posts have been about the poured sugar projects I have been working on for our Yule event Dec 3, 2011. Many different things can effect sugar work. Humidity, stirring and undissolved sugar crystals getting into the mixture as it cooks. Even the best, most prepared cooks can run into problems when working with boiled sugars.
Crystallization refers to the formation of sugar crystals in a sugar syrup. This will turn a smooth, clear candy into a lumpy, bumpy mess. The lollipop on the left is clear and smooth. The lollipop on the right is cloudy and gritty.
You often do not know that crystallization will happen until after it is poured. Once it has solidified, problems will be very apparent. The bishop chess piece does not have a smooth surfaced back. When it is broken, you can see the crystal formation through out the entire piece.
It is important to start with a clean cooking pot and clean molds. The use of “interfering agents” will help too.Interfering agents are added in the beginning of the recipe before the sugar syrup begins to boil. Common agents include corn syrup, glucose, and honey. Often acids like cream of tartar, lemon juice, or vinegar will be used. Vinegar helps keep clear candy “more clear”, longer as the cooking temperature gets above the soft crack stage. Most professional chefs use a sugar called isomalt, when doing poured sugar work.
Isomalt is out of period for SCA confectionery work. I prefer to use a wet pastry brush to brush down the sides of my pot as the sugar boils. Once it hits 245, the chemistry changes and the boil does not throw as much saturated sugar water up the sides of the pan. I will add a tablespoon of corn syrup and a splash of vinegar to the mixture, especially when the weather is unpredictable and unseasonably humid.