Sugar Stages
Sugar stages are the named temperature ranges a boiling sugar syrup passes through as it loses water. Each stage corresponds to a sugar concentration, and that concentration decides whether the cooled candy is a syrup, a chewy caramel, or a glass-hard lollipop.
Why temperature tracks texture
Pure water boils at 100 °C / 212 °F at sea level. Dissolved sugar raises the boiling point, and the more water boils away, the higher it climbs. So the thermometer is really a concentration meter: read the temperature and you know roughly how much water is left.
The stages
| Stage | Temperature | Approx. sugar | Cold-water test | Used for |
|---|---|---|---|---|
| Thread | 106–112 °C / 223–234 °F | 80% | Thin thread, dissolves | Syrups, candied fruit |
| Soft ball | 112–116 °C / 235–240 °F | 85% | Soft ball, flattens | Fudge, fondant, Italian meringue |
| Firm ball | 118–120 °C / 245–248 °F | 87% | Firm but pliable ball | Soft caramels |
| Hard ball | 121–130 °C / 250–265 °F | 92% | Hard ball, still mouldable | Nougat, marshmallows, divinity |
| Soft crack | 132–143 °C / 270–290 °F | 95% | Strands that bend | Taffy, butterscotch |
| Hard crack | 146–154 °C / 295–310 °F | 99% | Brittle strands that snap | Lollipops, toffee, brittle |
| Caramel | 160–180 °C / 320–356 °F | ~100% | Amber liquid | Caramel sauce, spun sugar, praline |
The climb is slow at first and then fast. It can take 10 minutes to reach soft ball and under a minute to go from hard crack to scorched, because there is so little water left to absorb heat.
Getting accurate readings
Calibrate. Put your thermometer in boiling water. If it reads 99 °C, everything you read later is 1 °C low; adjust targets accordingly.
Adjust for altitude. Water boils about 1 °C lower per 300 m of elevation (2 °F per 1,000 ft). At 1,500 m, take soft ball off at about 107–111 °C / 225–230 °F.
Keep the probe in the syrup, not touching the pan. Tilt the pan if the batch is shallow.
Pull it early. Residual heat keeps cooking the syrup for a few seconds, so remove it 1–2 °C before the target.
Why ingredients shift the stages
Butter, cream, and milk in caramels add water and proteins, so the syrup takes longer to reach temperature and browns sooner through the Maillard reaction. Corn syrup and honey are hygroscopic, so candies made with them stay a touch softer at the same temperature.
Chef Fizz says: Humid day? Cook hard candy 1–2 °C higher. The air will try to give back the water you just boiled off.
Questions
What temperature is the soft ball stage?
Soft ball is 112–116 °C / 235–240 °F. A drop of syrup in cold water forms a soft, squishy ball that flattens when you take it out, which is right for fudge, fondant, and Italian meringue.
How do I test sugar stages without a thermometer?
Drop a little syrup into a glass of very cold water and feel it. A thread that dissolves is thread stage, a squishy ball is soft ball, a firm ball is firm ball, bendable strands are soft crack, and brittle strands that snap are hard crack.
Why does altitude change sugar stage temperatures?
Water boils at a lower temperature at altitude, so syrup reaches each concentration at a lower reading. Subtract about 1 °C for every 300 m (2 °F per 1,000 ft) above sea level, or calibrate against your local boiling point.
What stage is caramel?
Caramel starts after hard crack, around 160 °C / 320 °F, when nearly all the water is gone and sucrose begins to break down. Light caramel is about 160–170 °C / 320–338 °F; dark caramel goes up to about 180 °C / 356 °F.