Candy Temperature Chart

The candy stages and their temperatures

Sugar syrup passes through a series of stages as it cooks, and each stage has a name and a temperature band. The names come from the old cold water test, where a spoonful of hot syrup was dropped into cold water and the result was felt with your fingers. A thermometer gives you the same answer faster and with less burned skin.

The ranges matter more than any single number. Fudge pulled off the heat at 235°F is soft and creamy, while the same recipe taken to 239°F is firm enough to cut. Four degrees is the whole difference, which is why a candy thermometer earns its place in the drawer.

Worked example: toffee to hard crack at sea level

Say you are making peanut brittle and the recipe calls for hard crack. At sea level that means 300 to 310°F, and for brittle you want the top of the range so it snaps instead of bending.

• Target: 305°F
• Sugar, corn syrup and water boiled together, stirred only until the sugar dissolves
• Thermometer clipped to the pan, bulb in the syrup but not touching the bottom
• At 305°F, pull the pan off the heat and stir in the baking soda and peanuts
• Pour onto a buttered sheet and cool for about 45 minutes before breaking

Two numbers decide whether this works. First, the syrup has to reach 305°F, not 290°F. Below the hard crack band the brittle stays chewy and bends instead of snapping. Second, the thermometer has to be right. A thermometer that reads 5°F high takes you to 310°F when you think you are at 305°F, and 5°F is enough to push brittle toward a burnt, bitter edge.

If your candy comes out grainy, temperature was not the problem. Grainy candy means sugar crystals formed, usually because the syrup was stirred after it started boiling or because a stray crystal from the side of the pan fell back in. Keep the sides clean with a wet pastry brush and leave the spoon alone once it boils.

Worked example: cooking candy in Denver or another high city

Water boils at a lower temperature the higher you go, so sugar syrup reaches every stage at a lower reading. The rule of thumb is to subtract about 2°F for every 500 feet above sea level.

• Denver, 5,280 feet: 5,280 / 500 = 10.6, times 2 = about 21°F lower
• Hard crack at sea level is 305°F, so in Denver it is about 284°F
• Soft ball at sea level is 235°F, so in Denver it is about 214°F
• Salt Lake City, 4,300 feet: about 17°F lower, so hard crack lands near 288°F

The better method is to measure your own boiling point and work from that. Boil a pan of water, read the thermometer in the boiling water, and note the number. In Denver that comes out near 202°F instead of 212°F, a difference of 10°F. Your candy temperatures shift by roughly the same amount, so subtract that difference from every target on the chart.

Above about 3,000 feet the cold water test becomes the safer check, because the thermometer adjustment grows and small errors compound. Candy made at altitude also sets faster and dries quicker, so work with a little more water in the recipe than a sea-level version calls for, and cover the pan between checks.

The cold water test when there is no thermometer

Before thermometers were common, cooks used a glass of cold water and their fingers. The method still works, and it is a good backup when a thermometer battery dies mid-batch.

Drop a small spoonful of hot syrup into a cup of cold water, let it sit for a second, then fish it out and squeeze it:

• Thread: the syrup spins a thin, weak thread that does not hold
• Soft ball: it forms a ball that flattens as soon as you pick it up
• Firm ball: the ball holds its shape but gives under pressure
• Hard ball: the ball is firm and only bends with effort
• Soft crack: it separates into threads that bend before they break
• Hard crack: the threads snap cleanly and feel brittle

The test reads about 2 to 4°F late compared with a thermometer, because the syrup cools as it hits the water. It is also hard to judge at the soft ball stage, where the gap between soft and firm is narrow. Use it as a cross-check, not as your main instrument, and always keep your fingers clear of syrup above 250°F, which causes a serious burn.

Why humidity, pan material and sugar type move the numbers

Three things shift candy temperature away from the chart on a given day. The first is humidity. Sugar syrup absorbs water from the air, and on a rainy day the syrup stays wetter, so you may need to cook a few degrees past the chart to hit the same texture. The effect is small for hard candy and noticeable for fudge and fondant.

The second is the pan. A heavy pan with a thick base spreads heat evenly and holds temperature; a thin pan develops hot spots, and the thermometer can read low while one corner of the syrup scorches. Dark pans and cast iron run hotter than light aluminum, so you may need to lower the burner rather than extend the time.

The third is the sugar itself. Recipes that include corn syrup, honey, or an acid like lemon juice behave differently because those ingredients interfere with crystallization. Corn syrup and cream of tartar keep the syrup smooth but can also change the temperature at which it sets, so a fudge that works with corn syrup may need a couple of extra degrees without it. Read your recipe as a starting point, not a guarantee.

Calibrate the thermometer before you cook

A candy thermometer that is off by 8°F will ruin a batch, and most home thermometers drift over time. Two checks catch nearly every problem, and both take about five minutes.

Ice water check. Fill a glass with crushed ice and a little water, stir for a minute, and put the probe in without touching the sides or bottom. It should read 32°F. If it reads 36°F, your thermometer runs 4°F high and you should subtract 4 from every target.

Boiling water check. Boil a pan of water and read the thermometer in the middle of the boil, not against the pan. At sea level it should read 212°F. This check also gives you your altitude adjustment for free, because the gap between 212 and what you read is roughly the amount to subtract from candy temperatures.

Digital instant-read thermometers are usually accurate to within 1°F and recover fast, but many are not built to sit in boiling syrup for ten minutes. A clip-on candy thermometer is slower but made for the job. Whichever you use, the National Institute of Standards and Technology explains how thermometers are calibrated, and the USDA Food Safety and Inspection Service covers the temperature side of cooking and food safety if you are making candy for a crowd. The FDA has plain-language storage guidance for the finished batch.