• Candy mixtures should boil at a moderate, steady rate over their entire surface. To guide you, we suggest range-top temperatures. However, you may need to adjust the temperature of your range in order to maintain the best rate of cooking, which ensures that the candy will cook within the recommended time. Cooking too fast or slow makes candy too hard or soft. When stirring a hot candy mixture, use a wooden spoon.
• The most accurate way to test the stage of the hot mixture is to use a candy thermometer. Be sure to check the accuracy of your thermometer every time you use it. To test it, place the thermometer in a saucepan of boiling water for a few minutes, then read the temperature. If the thermometer reads above or below 212 degrees F, add or subtract the same number of degrees from the temperature specified in the recipe and cook to that temperature. And don't forget to add or subtract that same number of degrees from the cooling temperature in recipes where candy mixtures need to cool.
• If a candy thermometer is not available, use the corresponding cold-water test described below. Start testing the candy shortly before it reaches the minimum cooking time.

For the cold-water test, spoon a few drops of the hot candy mixture into a cup of very cold (but not icy) water. Using your fingers, form the drops into a ball. Remove the ball from the water; the firmness will indicate the temperature of the candy mixture. If the mixture has not reached the correct stage, continue cooking and retesting, using fresh water and a clean spoon each time.

Thread stage (230 to 233 degrees F): When a teaspoon is dipped into the hot mixture, then removed, the candy falls off the spoon in a 2-inch-long, fine thin thread.

Soft-ball stage (234 to 240 degrees F): When the ball of candy is removed from the cold water, the candy instantly flattens and runs over your finger.

Firm-ball stage (244 to 248 degrees F): When the ball of candy is removed from the cold water, it is firm enough to hold its shape, but quickly flattens.

Hard-ball stage (250 to 266 degrees F): When the ball of candy is removed from the cold water, it can be deformed by pressure, but it doesn't flatten until pressed.

Soft-crack stage (270 to 290 degrees F): When dropped into the cold water, the candy separates into hard, but pliable and elastic, threads.

Hard-crack stage (295 to 310 degrees F): When dropped into the cold water, the candy separates into hard, brittle threads that snap easily.