When making candy, one of the most important steps is cooking the sugar syrup to the right temperature. This ensures the candy sets up with the correct texture. The final stage of cooking candy is known as the hard crack stage. Recognizing when the syrup has reached this point takes some practice. Here is a guide to determining when candy has reached the hard crack stage.
What is the hard crack stage?
As a sugar syrup is heated, the water evaporates, increasing the sugar concentration. This causes the syrup’s temperature to rise. The different stages of cooking candy correspond to different syrup temperatures as the water cooks out.
The stages of cooking candy are:
- Thread (230-235°F)
- Soft ball (235-240°F)
- Firm ball (245-250°F)
- Hard ball (250-265°F)
- Soft crack (270-290°F)
- Hard crack (300-310°F)
The hard crack stage occurs between 300-310°F. At this stage, nearly all the water has evaporated from the syrup. This results in a very concentrated sugar solution that will harden into a brittle, glass-like candy when cooled.
Checking syrup temperature
The most accurate way to assess what stage a sugar syrup is at is by measuring its temperature. To do this, you will need a candy thermometer. There are a few types of candy thermometers:
- Traditional candy thermometers – These have a long glass tube with temperature markings and are placed directly into the syrup.
- Instant-read thermometers – These quick-response digital thermometers can also be used. Make sure they can read high temperatures up to at least 400°F.
- Infrared thermometers – These non-contact thermometers measure the infrared energy emitted from the syrup’s surface. They can’t be fully submerged but work well for a surface reading.
To effectively measure the syrup temperature, make sure the thermometer bulb is submerged in the syrup but not touching the bottom of the pan. Read the temperature slowly rising to the hard crack stage. When it reaches 300-310°F, you’ve reached hard crack!
Cold water test
An alternative way to test the syrup stage is the cold water test. This involves dripping a small amount of hot syrup into cold water and observing the consistency as it cools. For the hard crack stage, the syrup will solidify into hard, brittle threads that break when bent.
To do a cold water test for hard crack stage:
- Fill a cup with cold tap water. Have this ready near the stove.
- When you think the syrup is near hard crack stage, drip a small amount into the cold water.
- Let it cool for a few seconds. The syrup should form thick, brittle threads that crack when you try to bend them.
- If the threads are still pliable and bendable, the syrup needs to be cooked longer. Test again in a few minutes.
- Once it passes the brittle thread test, you’ve reached hard crack stage!
With some practice, you can get the hang of identifying hard crack stage using the cold water test. But for peak accuracy, rely on an actual thermometer reading.
Observing syrup changes
In addition to temperature and water tests, you can look for visual and physical changes as the syrup cooks:
- At hard crack stage, the syrup will turn an amber color.
- The bubbles will become very small right before the hard crack stage is reached.
- The syrup will thin out and become less viscous due to the high concentration of dissolved sugar.
- As it approaches 300°F, the syrup will start to emit smoke.
These signs can give you clues that the hard crack stage is imminent or has been reached. But it’s still best to confirm with a thermometer reading.
Testing finished candy
Once the syrup reaches hard crack stage, you can test the final cooled candy to ensure it has the right brittle texture. Characteristics of properly cooked hard crack candy include:
- Very hard and brittle
- Glass-like clarity
- Cracks cleanly when broken
- Does not bend or flex when handled
- May “snap” when biting into it
If the finished candy seems soft or chewy instead of crispy and brittle, the syrup likely didn’t cook long enough to reach the hard crack stage.
Troubleshooting
Here are some potential issues and how to troubleshoot them:
Candy never reaches hard crack stage
- Ensure your thermometer is accurate. Test it in boiling water which should read 212°F at sea level.
- Use a heavy, high-sided pot which promotes even heating. The temperature can vary in a shallow, lightweight pan.
- Don’t let sugar crystals form on the side of the pan. Brush down any crystals with a wet pastry brush.
- Make sure to bring the syrup to a full rolling boil when cooking. A lazy simmer won’t cause the temperature to rise.
- Cook over medium-high heat. Too low of a flame will prolong reaching the target temperature.
Candy is brittle but opaque
- The syrup cooled too quickly after cooking and didn’t have time to set properly. Next time, pour it onto a cool surface to help slow cooling.
- There may have been undissolved sugar crystals in the syrup. Heat until it’s perfectly clear with vigorous stirring.
- You got it above hard crack temperature. Don’t let it exceed 320°F which can burn the sugar.
Candy is sticky or soft
- The syrup didn’t cook to a high enough final temperature. Re-cook until it reaches 300°F on a thermometer.
- There was excess moisture in the ingredients. Use dry ingredients and cook thoroughly.
- It was exposed to humidity while cooling. Let it dry in a low humidity environment.
Conclusion
Making candy that turns out perfectly brittle requires taking the sugar syrup up to the hard crack stage between 300-310°F. Use a thermometer for the most precision. But the cold water test and visual cues can also help identify when hard crack has been reached. If the finished candy doesn’t have that signature crisp, glass-like texture, try troubleshooting your process to ensure the syrup is fully cooking to the right temperature.
With the right techniques, you’ll be able to make incredible hard candies, lollipops, brittles and more by mastering the art of cooking sugar to the hard crack stage.
FAQ
What is the difference between hard crack and soft crack stage?
Soft crack stage is between 270-290°F. At this stage, the syrup forms flexible threads when dropped in cold water. Hard crack stage is between 300-310°F. The syrup forms brittle, glass-like threads when dropped in cold water.
Can I make hard candy without a thermometer?
It’s possible but not ideal. A thermometer gives the most accurate readout of the syrup temperature. Relying on visual cues or the cold water test takes practice. Using a thermometer is recommended for consistent, reliable results.
Is it bad if I accidentally go past hard crack stage when making candy?
Going above 310°F can burn the sugar, giving it a bitter taste and opaque appearance. The candy may caramelize too much. Try not to let the temperature overshoot more than 5-10°F past hard crack stage.
Should I stir the syrup when cooking candy to hard crack stage?
Gentle, occasional stirring can help prevent hot spots and burning. But don’t stir constantly – this can cause crystallization. Stir just enough to maintain an even temperature and dissolve any grains of sugar.
Can I make substitutions when cooking candy to hard crack stage?
It’s best to follow recipes exactly, especially for the sugar-to-water ratio. Substituting other sugars or liquids can inhibit reaching the target temperature. Stick to white granulated sugar and water for reliable hard crack candy.
Candy Recipes Reaching Hard Crack Stage
Classic Hard Candy
This basic recipe results in colorful, flavored hard candy that pops in your mouth.
| Ingredient | Amount |
|---|---|
| Sugar | 2 cups |
| Light corn syrup | 1/4 cup |
| Water | 1/4 cup |
| Flavor extract (e.g. vanilla, mint, lemon) | 1 tsp |
| Food coloring | As desired |
Instructions:
- Grease a baking sheet and set aside.
- In a heavy saucepan, combine the sugar, corn syrup and water. Bring to a boil over medium-high heat, stirring to dissolve sugar.
- Continue boiling until it reaches 300°F hard crack stage. Add flavoring and food coloring if using.
- Remove from heat and quickly pour onto prepared baking sheet. Allow to cool completely.
- Break into pieces and enjoy!
Peanut Brittle
This classic peanut candy achieves maximum crunch at the hard crack stage.
| Ingredient | Amount |
|---|---|
| Sugar | 2 cups |
| Light corn syrup | 1/4 cup |
| Water | 1/4 cup |
| Roasted peanuts | 2 cups |
| Butter | 2 Tbsp |
| Baking soda | 1 tsp |
| Salt | 1/4 tsp |
Instructions:
- Grease a baking sheet and set aside.
- In a saucepan, combine sugar, corn syrup and water. Bring to a boil over medium heat, stirring to dissolve sugar.
- Continue boiling until 300°F hard crack stage is reached. Stir in peanuts.
- Remove from heat and stir in butter, baking soda and salt. Mix well to combine.
- Quickly pour onto prepared baking sheet. Allow to cool completely before breaking into pieces.
Toffee
This recipe uses the hard crack stage to achieve the signature brittle, crunchy texture of toffee candy.
| Ingredient | Amount |
|---|---|
| Butter | 1 cup |
| Sugar | 1 cup |
| Light corn syrup | 1 Tbsp |
| Water | 1 Tbsp |
| Chocolate chips | 6 oz |
| Flaked sea salt | 1/4 tsp (optional) |
Instructions:
- Line a baking sheet with parchment paper or foil.
- In a saucepan, melt butter over medium heat. Stir in sugar, corn syrup and water. Bring to a boil.
- Continue boiling, without stirring, until 300°F hard crack stage is reached.
- Remove from heat and quickly pour onto prepared baking sheet. Allow to cool and harden.
- Once cool, melt chocolate chips and spread evenly over the toffee. Sprinkle with sea salt if desired.
- Allow chocolate to set then break into pieces.