Science of Candy: What's Special About Fudge? | Exploratorium (2024)

What’s special about fudge?

Science of Candy: What's Special About Fudge? | Exploratorium (1) Fudge is one of the rare exceptions to the rule that sugar crystals are not desirable in candy. Tiny microcrystals in fudge are what give it its firm texture. The crystals are small enough, however, that they don’t feel grainy on your tongue, but smooth.

While you ultimately want crystals to form, it's important that they don't form too early. The key to successful, nongrainy fudge is in the cooling, not the cooking. The recipe calls for heating the ingredients to the soft-ball stage, or 234° F, then allowing it to cool undisturbed to approximately 110° F. If you stir during this cooling phase, you increase the likelihood that seed crystals will form too soon.

Science of Candy: What's Special About Fudge? | Exploratorium (2) A seed crystal is a surface that sucrose molecules (that's the sugar) can begin to attach themselves to—it could be a few sucrose molecules stuck together, a piece of dust, or even a little air bubble. Once a seed crystal forms, it grows bigger and bigger as the fudge cools. A lot of big crystals in fudge makes it grainy.

By letting the fudge cool without stirring, you avoid creating seed crystals. Stirring would help sucrose molecules "find" one another and start forming crystals. Stirring also introduces air, dust, and small dried bits from the walls of the saucepan—all potential seeds for crystal formation.

When the fudge has cooled to about 110° F, you want to start the crystallization process. You start to stir, and keep stirring, until the candy becomes thick. The more you stir, the more crystal seeds you get. But instead of getting a few huge crystals (and grainy candy), you get lots and lots of tiny crystals, which make for thick, smooth candy.

There are two other candies that deliberately employ sugar crystals. One is fondant, a wetter version of fudge that you find inside soft-center chocolates. The other is rock candy, for which a sugar solution is left for days to form enormous crystals.

Think you get it? Try making fudge or rock candy yourself!

Science of Candy: What's Special About Fudge? | Exploratorium (2024)

FAQs

Science of Candy: What's Special About Fudge? | Exploratorium? ›

Fudge is one of the rare exceptions to the rule that sugar crystals are not desirable in candy. Tiny microcrystals in fudge are what give it its firm texture. The crystals are small enough, however, that they don't feel grainy on your tongue, but smooth.

What is the secret to good fudge? ›

Valuable tips for successful fudge
  • Don't stir during cooking. Fudge can be cooked on the stove or in the microwave. ...
  • Avoid crystallization. During cooking, sugar crystals can stick to the sides of the pan. ...
  • Let cool before beating. After being cooked, the sugar must crystallize again to create fudge. ...
  • Beat the mixture.

How does fudge relate to chemistry? ›

When making fudge, heat and acid work together to convert sucrose – basic white sugar – into its two components, glucose and fructose. When these sugars are present, they prevent sucrose from turning into big sugar crystals.

What is the science behind candy? ›

In general, candy is made by dissolving sugar into water to create a solution. Granulated sugar, the most common type used in candy-making, is sucrose, a disaccharide molecule made up of glucose and fructose. When you force these two molecules to break apart, a very tasty reaction occurs: caramelization.

What is the secret to smooth fudge that is not gritty? ›

Once the sugar has dissolved and the mixture has come to a boil, do not stir it. If you do, the sugar can crystallize, giving your fudge a gritty texture. As you beat the fudge, pay attention to color and texture. Once the fudge loses its sheen and thickens, put down your spoon.

What makes fudge special? ›

Fudge is one of the rare exceptions to the rule that sugar crystals are not desirable in candy. Tiny microcrystals in fudge are what give it its firm texture. The crystals are small enough, however, that they don't feel grainy on your tongue, but smooth.

Why is my fudge not hard enough? ›

The amount of time you cook fudge directly affects its firmness. Too little time and the water won't evaporate, causing the fudge to be soft. Conversely, cook it too long and fudge won't contain enough water, making it hard with a dry, crumbly texture.

What is the principle of fudge? ›

Heating the sugar and milk mixture allows the milk to dissolve more and more sugar, and by the time the mixture is boiling, all the sugar is dissolved. The general principle is that at a particular temperature, a given solvent (in this case, milk) can dissolve only so much of a particular solute (sugar).

Why is fudge called fudge? ›

The exact origin and inventor of this delicious confection are hotly debated. However, many believe the first batch of fudge was created by accident when American bakers “fudged” a batch of caramels. Hence the name “fudge.”

Why is fudge so good? ›

Between its deeply rich flavor and its silky texture, fudge makes a brilliant treat to pair with coffee. The sweet and bitter flavors complement one another perfectly, making for an unstoppable combination.

How do you describe high quality fudge? ›

High-quality fudge tastes smooth and creamy because it contains small sugar crystals. It has a deep brown color and a satiny sheen. Poor-quality fudge tastes grainy because it contains large sugar crystals.

What are 5 facts about candy? ›

10 of the coolest candy facts:
  • The world's first candy was made in ancient Egypt. ...
  • The first candy cane was made in the late 1600s. ...
  • The world's largest candy bar weighed over 12,000 pounds. ...
  • The Hershey's Kiss got its name from the sound of the machine that makes them.
May 4, 2023

What is the physics of candy making? ›

To make candy, sugar is first heated to a high temperature so that it melts . The scalding solution is then then cooled into a solution that is supersaturated. The supersaturation is considered unstable, forcing the sugar molecules to crystallize into a solid.

Why is my 3 ingredient fudge not setting? ›

Why won't my 3 ingredient fudge set? This often happens when the condensed milk and chocolate chip mixture isn't hot enough to start. Everything must be completely melted before it is transferred to the pan to cool.

What happens if you cook fudge too long? ›

Too cooked

The result is hard and brittle fudge. To save the fudge, put it in a saucepan with 45 to 60 ml (3 or 4 tbsp.) of 35% cream and bring to a boil, stirring until the sugar is completely melted. Then let it boil without stirring until the thermometer reaches 114 to 115 °C (237 to 239 °F).

How to make fudge softer? ›

Keep a bowl of water inside the microwave along with the fudge to create moisture for the pieces to inhale. Next, microwave the fudge pieces for just 10 seconds. So it will become soft but it won't have the correct consistency as before.

Do you stir fudge when it's boiling? ›

Avoid Stirring Once the Mixture Comes to a Simmer

Another key part of a successful fudge texture is when you stir the mixture. Stirring the sugar and milk during the initial stages of cooking allows the sugar to dissolve. However, once the mixture comes to a boil, it's time to put the spoon down.

Why do you add salt to fudge? ›

Salt: While some homemade fudge recipes do not call for salt, I find it essential for balancing out the sweetness of the condensed milk.

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