What is the Hard Crack Stage?

Tricia Christensen
Tricia Christensen

Hard crack stage is the hottest stage in candy making before you begin making caramels, which are heated to caramel stages. Hard crack is used for candies like English toffees and some nut brittles. When you cook sugar with other ingredients together to make candy, the heat temperature rises, reducing the moisture in the candy significantly. During this stage, all but 1% of the moisture in the original ingredients has been evaporated.

Hard crack may be used for candies like English toffees.
Hard crack may be used for candies like English toffees.

On a candy thermometer, hard crack stage is defined as between 300-310 degrees F (148.89-154.44 degrees C). It is highly recommended that you use a candy thermometer to reach this stage, since you can easily miss it by a few degrees and produce candy in soft crack stage, or you may caramelize or burn your sugar. If the candy becomes a deep, dark brown you’ve probably passed hard crack, and if it begins to smoke, you’ve very likely burned the candy.

Hard crack may be used for nut brittles.
Hard crack may be used for nut brittles.

You can also tell when you’ve reached this stage by the way the candy drips off a spoon—it will have strands that are very stiff when they are dropped in water. When you remove these strands from the water, you’ll note that they break very easily, representing the “crack” of hard crack stage.

If you test your candy in this manner, you should do it right next to your stove, because it’s important to keep an eye on the candy. You should also exercise extreme care when performing a water test with candy. The high temperature can cause severe burns. Use a long spoon to remove some of the heated sugar, and use oven mitts for extra safety. Though it can be fun to having children help you prepare goodies, you might want to keep them out of the cooking process when you must heat sugar to this high of a temperature to protect little hands from burns.

As your sugar syrup reaches higher temperatures, even before it hits the hard crack stage, you may want to brush down the sides of the pot, because sugar can stick to the sides and granulate. Most recipes recommend that you don’t stir the sugar once it is boiling unless you are adding nuts. If you perform the spoon test to determine this stage, many chefs recommend using a warm metal or wooden spoon, because the test can be corrupted if you use a cold metal spoon.

Since hard crack stage cools so quickly, it is very important to pour the candy out immediately into a waiting pan or onto a marble slab. Simply smooth the candy out and allow it to set and cool. If you’re making recipes like English toffee, you need to spread chocolate chunks or chips onto the candy while it is still warm so the chocolate will melt.

A candy thermometer will be needed to reach the hard crack stage.
A candy thermometer will be needed to reach the hard crack stage.
Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent wiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Discussion Comments


I think fudge is one of the easiest candies to make. Once I started making fudge in the microwave, I have not gone back to the other way. It seems like I tried several recipes before I found one that worked good every time. Sometimes you just never know when you are making candy. The humidity in your house can even make a difference.

The nice thing about making it in the microwave is that you don't even have to worry keeping track of the hard crack stage. You can still use a candy thermometer if you want to make sure you have the right temperature, but once you get used to your recipe, you should be able to tell by what it looks like.


Every year I make peanut brittle for our holiday celebrations. I have a few microwave cookbooks that have several easy candy recipes in them, but I have the best luck making candy the old fashioned way.

When making peanut brittle, I keep a candy thermometer in the pan at all times. First, the mixture of corn syrup and sugar has to reach the soft crack stage. This usually takes 20 minutes or so, but you must watch it at all times.

It seems to take a long time for it to finally make it to the hard crack stage. If you make candy very often, you will become familiar with what the texture looks and smells like, but I still rely on the thermometer for an accurate reading.


This is supposedly a really difficult thing to achieve properly. I have a friend who is a really good cook, but she almost never makes candies because they're so difficult to make. She said it takes a lot of practice.

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