What Temperature Should Toffee Reach?

What it means

• Hard-crack is the classic candy stage for toffee: roughly 300-310°F / 149-154°C on a candy thermometer.
• At this point almost all the water has boiled off, so the cooled sugar sets hard and brittle instead of chewy.
• Stopping short (in the soft-crack or caramel range) gives a softer, stickier candy; going much higher scorches the sugar and turns it bitter.

Action steps

1. Clip a calibrated candy thermometer to the pan so the tip sits in the syrup but not touching the bottom.
2. Cook over medium heat without stirring too aggressively once it is boiling steadily.
3. Pull the pan off the heat right at 300-310°F, since residual heat will keep raising the temperature.
4. Adjust down a few degrees at high altitude, where water boils cooler.

Risks & deadlines

• Above about 315°F the sugar quickly scorches and turns acrid — watch closely near the end.
• Hot sugar syrup causes severe burns; keep children away and never touch or taste it straight from the pan.