Soft-crack stage refers to a specific temperature range when cooking sugar syrups. Soft-crack stage occurs at 270 - 290 F. At this stage, the sugar concentration of the syrup is 95 percent, which determines how pliable or brittle the candy will be. The soft crack stage is used for saltwater taffy, nougat, toffee, and butterscotch.
Heating Sugar Syrup to Soft Crack Stage
As you are heating the syrup and it is approaching the soft crack stage, the bubbles on the top become smaller, and they are thicker and closer together.
This is due to more of the water in the sugar solution having been boiled away. You can determine the temperature with a candy thermometer, or you can use the cold water method. A candy thermometer might not be accurate in pinpointing the soft crack stage, depending on the altitude and other local conditions.
Cold Water Method to Determine Soft Crack Stage
Many home candy makers determine the soft-crack stage 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. The soft crack stage has been reached when the syrup forms a firm but pliable threads. They will bend slightly before breaking (cracking).
The difference between a hard ball and soft crack is that at hard ball stage, the sugar forms a firm but pliable ball rather than threads. The difference between soft crack and hard crack is that at the hard crack, the threads will not bend and will simply break if you try to bend them.
Candy Cooked to Soft Crack Stage
Many different recipes require cooking sugar syrup to soft crack stage, commonly including toffees, nougat, taffy, and butterscotch. Often, candies that are cooked to soft crack stage feature a caramelized sugar flavor and a hard, pleasingly crunchy texture.
Temperature Ranges for Cooking Sugar Syrups
- Thread Stage: 223 - 235 F
- Soft Ball Stage: 235 - 245 F
- Firm Ball Stage: 245 - 250 F
- Hard Ball Stage: 350 - 266 F
- Soft Crack Stage: 270 - 290 F
- Hard Crack Stage: 300 - 310 F
- Caramel Stage: 320 - 350 F
Some candy cooking instructions fall into the crack between soft crack and hard crack, such as butterscotch which is cooked to between 290 and 300 F, and brittles which are cooked to between 295 and 300 F.
Cooking Safety with Hot Sugar Syrup
Hot sugar syrup must be handled carefully. At the soft-crack stage, it can burn your skin if it spatters. The sugar syrup will be thick and sticky, which holds it in place against the skin and increases the risk of a burn when you come into contact with it. It doesn't run off as hot water would. It's important to use techniques and utensils that reduce the risk of splashes and spatters with hot syrup.