Cooking up your own candy is as delicious as it is fun. Experienced candy makers know that keeping the sugar from crystallizing during cooking is a big problem. There’s a simple solution: Heat the sugar over low heat, without stirring, until it’s completely dissolved. To dissolve any sugar crystals that cling to the sides of the pan, cover the pan with a tight-fitting lid and continue cooking the syrup for three to four minutes. The steam that’s generated will melt these pesky sugar crystals.