Candy Making Temperature Stages: Soft Ball to Hard Crack

How the stages work

A sugar syrup starts as sugar dissolved in water. As it boils, water leaves as steam, the share of sugar goes up and the boiling temperature climbs with it. The Exploratorium science museum puts it simply: the highest temperature the syrup reaches tells you what it will be like once it cools. That is why candy recipes name a temperature or a stage, and why the stages are named after what a drop of syrup does in cold water.

The Exploratorium chart also gives the sugar concentration at each stage. It shows how little water is left near the top of the scale:

Between soft ball and hard crack the sugar share rises from 85% to 99%. At the clear-liquid stage all the water has boiled away.

Sugar stage temperatures in °F and °C

The three charts use the same stage names, but their ranges differ by a few degrees. Here are three charts side by side: the Exploratorium, the Candy Making Project book from Ohio State University (OSU) Extension in Fairfield County, and Colorado State University's (CSU) Food Smart Colorado page. All three give sea-level temperatures in Fahrenheit only; the Celsius values are converted and rounded to the nearest degree.

CSU's table starts at soft ball and has no thread stage. The differences are mostly at the edges: soft ball runs from 234°F to 245°F across the three charts, and hard ball tops out at 260, 265 or 266°F depending on the chart. When a recipe gives a number, cook to that number. The stage names are shorthand for a range, and the recipe writer picked a point inside it.

Past hard crack: caramel

Above the candy stages the sugar itself starts to change. The Exploratorium lists a clear-liquid stage at 320°F (160°C), where the melted sugar is light amber, and a brown-liquid stage at 338°F (170°C), where it browns as it caramelizes. Above about 350°F (177°C) the sugar begins to burn and turns bitter. The OSU chart gives one caramel range, 320–350°F (160–177°C), and describes the syrup as golden brown with a caramel smell.

To convert any other recipe temperature, use the temperature converter.

What each stage is used for

Each chart names the candies cooked to each stage. They mostly agree, and where they do not, the table shows it:

Two candies sit in different stages depending on the chart. Toffee is soft crack in the CSU table but hard crack in the Exploratorium chart, and nougat is hard ball for the Exploratorium but soft crack for OSU. Follow the temperature in the recipe you are using.

OSU also sorts candies into two families. Crystalline candies such as fudge, fondant and divinity hold tiny sugar crystals in a concentrated syrup. Non-crystalline candies such as caramels, taffy and peanut brittle have no crystals and are chewy or brittle. The family decides how you handle the syrup after it reaches temperature, covered further down.

The cold-water test

The cold-water test needs no thermometer and works as a check on one. CSU Extension calls it reliable at any elevation, and the Exploratorium recommends using both the test and a thermometer for the best accuracy.

1. Set a bowl of cold water next to the stove.
2. Drop about a teaspoon of syrup into the water. The OSU book uses 1 teaspoon per test and rinses the spoon in hot water before each one.
3. Let the drop cool for a moment, then feel it with your fingers and compare it with the table below.

The Exploratorium adds a sign you can see in the pan: at hard ball the syrup falls from the spoon in thick, ropy threads, and as it reaches soft crack the bubbles on top get smaller, thicker and closer together. At hard crack it warns you to let the sample cool in the water for a few moments before touching it.

Check your candy thermometer in boiling water

Several stages in the Exploratorium chart span only 5°F (2.8°C), so a thermometer that reads a few degrees off can land you in the wrong stage. Both OSU Extension and the University of Arkansas Cooperative Extension recommend a simple test before you cook. OSU says to do it before each use.

1. Bring a pan of water to a rapid boil.
2. Put the thermometer in so the bulb is fully under water but does not touch the bottom of the pan.
3. Read it at eye level while it is still in the boiling water.
4. At sea level it should read 212°F (100°C). Note how far off it is.

If the reading is off, the Arkansas extension article says to adjust your cooking temperatures by the difference, or to replace the thermometer. A worked example: your thermometer reads 214°F in boiling water at sea level, so it reads 2°F (1.1°C) high. For a recipe that says 240°F, cook until that thermometer shows 242°F. If it read low instead, you would cook to a lower number on its scale by the same amount.

The same rules apply when you cook the syrup. OSU says to clip the thermometer upright to the side of the pan with the bulb fully in the syrup and off the bottom. It also warns that a hot thermometer put under cold water will shatter, and that it should go into the pot clean and dry every time. CSU suggests a thermometer that reads to at least 400°F (204°C) and has a clip, and notes that an older thermometer containing mercury must be treated as hazardous waste if it breaks.

Altitude: lower the target

Water boils at a lower temperature the higher you live, and every stage shifts down with it. CSU Extension's rule is to lower the recipe's finish temperature by about 2°F for every 1,000 feet above sea level. The OSU and Exploratorium charts state the same rate as 1° per 500 feet. For a recipe that says 245°F:

CSU's more exact method uses your own boiling-water reading: subtract the difference between that reading and 212°F from the recipe temperature. If water boils at 203°F on your thermometer, that is 9°F below 212°F, and the 245°F recipe becomes 236°F.

This method has a useful side effect. Because you read the boiling point with the same thermometer you use for the syrup, the one subtraction covers both your elevation and any error in the thermometer. Do the boiling test, subtract once, and do not adjust a second time for altitude. The high altitude cooking and baking guide covers why water boils cooler up high and what else changes in the kitchen.

Humid and rainy days

Weather matters too. OSU Extension says to cook candy about 1 to 2° higher than usual on humid or rainy days, and the Arkansas extension article gives the same advice: a degree or two higher than the recipe states. That is about 0.6 to 1.1°C. Both prefer the simpler fix of waiting for a dry, cool day to make candy.

Keeping the syrup smooth

Grainy candy usually means sugar crystals got in where they were not wanted. CSU's Food Smart Colorado page says this applies to both families, crystalline and non-crystalline. Its steps:

• If the recipe uses butter, grease the sides of the saucepan with it before adding the other ingredients.
• Bring the liquid to a boil, take the pan off the heat and add the sugar.
• Return the pan to the heat and cover it long enough for steam to wash crystals down from the sides. OSU gives 2 to 3 minutes with a tight lid.
• Uncover so water can evaporate, and do not stir from then on. Cook to the temperature or the cold-water stage.
• Let the candy cool undisturbed. Any agitation can start crystals.
• For taffy, caramels and brittle, hold the saucepan about an inch above the cooling pan when pouring, and do not scrape out the last of the syrup.

Crystalline candies like fudge are the exception at the end: they are beaten on purpose, but only once the syrup has cooled. OSU explains that beating hot syrup makes a few large crystals and a coarse, grainy candy, while beating once it has cooled to about 104°F (40°C) makes many tiny crystals and a smooth, creamy one. Keep beating until it has crystallized all the way. Use the thermometer to tell when it has cooled that far.

Scaling, weighing and converting a candy recipe

Changing a candy recipe's size changes the amounts, not the stage. The target temperature describes how much water is left in the syrup, so a double batch still cooks to the same number. The recipe scaler multiplies the ingredient list; leave the temperatures as they are.

A bigger batch needs a bigger pan. OSU and the Arkansas extension article both say the pan must be large enough that the candy does not boil over, and the Arkansas article recommends a heavy pan so the candy does not scorch. Go by the thermometer and the cold-water test to know when the syrup is done.

If you prefer to weigh the sugar, butter or cream, the cups to grams converter turns the cup amounts into grams. For recipes written in Celsius, or to read a Fahrenheit thermometer against a metric recipe, use the temperature converter. Remember that a correction such as "2°F lower" is a difference, which is only 1.1°C, not the result of converting 2°F as a temperature.

Safety at the stove

Hard-crack syrup is around 300°F (149°C), far above the 212°F of boiling water, and OSU warns that hot candy syrup can spatter or spill and cause burns. Its candy project book opens with safety steps:

• Turn pan handles away from the front of the stove so the pan cannot be knocked off.
• Use oven mitts or potholders for anything hot from the stove or microwave.
• Stay with the syrup while it cooks. If you must leave, take it off the heat; it could burn, boil over or overcook.
• Keep a large bowl of clean cold water by the stove, because hot syrup can spatter or spill. For a small spatter burn, put the area in cold water or under cold running water right away until the pain stops.
• OSU then says to apply a sterile dressing and get treatment from a doctor. A burn larger than your hand should be treated as a serious burn: get help.

The Exploratorium's warning for the cold-water test bears repeating: let a hard-crack sample cool in the water for a few moments before you touch it.

The short version

1. Read the recipe's target temperature and stage. When a number is given, it wins over the stage range.
2. Test the thermometer in rapidly boiling water. Note the reading.
3. Subtract (212°F − your reading) from the target. That one step covers both altitude and thermometer error.
4. On a humid day, go about 1 to 2°F higher, or wait for a dry day.
5. Dissolve the sugar, cover briefly, then stop stirring.
6. Near the end, confirm with a cold-water test.
7. Cool undisturbed. Beat fudge only once it has cooled to about 104°F.

Frequently asked questions

Sources

• Exploratorium, Science of Cooking: Candy-making Stages (stage temperatures in °F, sugar concentration per stage, the cold-water description of each stage, candies per stage, clear-liquid, brown-liquid and burnt-sugar stages, use both a thermometer and the cold-water test, test the thermometer in boiling water, 1°F per 500 feet, let the hard-crack sample cool before touching)
• Ohio State University Extension, Fairfield County: Candy Making Project book, 2016 (candy temperature chart with usages, test the thermometer before each use in boiling water, bulb off the bottom of the pan, a hot thermometer shatters in cold water, 1° per 500 feet, 1 to 2° higher on humid days, crystalline candy tips, cooling to about 104°F before beating, kitchen safety and burns)
• Colorado State University, Food Smart Colorado: Candy Making at High Elevation (sea-level finish temperatures, cold-water test stage and syrup color by candy type, 2°F per 1,000 feet, thermometer features, mercury thermometers as hazardous waste, tips against sugar crystals)
• Colorado State University Extension: High Elevation Food Preparation Guide, reviewed October 2025 (humidity and elevation both affect candy, lower the finish temperature by the difference between your boiling water and 212°F, cold-water test reliable at any elevation)
• University of Arkansas Cooperative Extension Service, Miller County: Test Candy Thermometer for Accuracy before Making Holiday Memories (boiling-water test, read at eye level, adjust or replace, heavy pan of the right size, a degree or two higher on humid days)

Written by Tobias. Updated October 22, 2026.