Soft-crack stage refers to a specific temperature range when cooking sugar syrups. Soft-Crack Stage occurs at 270-290 degrees. This stage can be determined by dropping a spoonful of hot syrup into a bowl of very cold water. Remove the candy from the water and pull it apart between your fingers. Soft-crack stage has been reached when the syrup forms firm but pliable threads.
Many different recipes require cooking candy to soft-crack stage, commonly including toffees, brittles, and butterscotch. Often, candies that are cooked to soft-crack stage feature a caramelized sugar flavor and a hard, pleasingly crunchy texture.