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300° F310° F
Sugar concentration: 99%
hard-crack stage is the highest temperature you are likely to
see specified in a candy recipe. At these temperatures, there
is almost no water left in the syrup. Drop a little of the molten
syrup in cold water and it will form hard, brittle threads.
Toffee, nut brittles, and lollipops
are all cooked to the hard-crack stage.