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

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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.

Beating the syrup caused the formation of crystallization nuclei, anchor points to which sugar molecules attach to form crystals. Few crystallization nuclei will form in syrup that is still hot, and sugar molecules will readily attach to them. The crystals grow so easily, and the result is really grainy fudge.

Although fudge often contains chocolate, fudge is not the same as chocolate. Chocolate is a mix of cocoa solids, cocoa butter and sometimes sugar and other flavorings and is hard and brittle. Fudge is a mixture of sugar, dairy and flavorings that is cooked and cooled to form a smooth, semi-soft confection.

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.

The key to creamy, luscious fudge is controlling crystal formation. If the sucrose (table sugar) crystals are small, the fudge will feel creamy and smooth on your tongue. But if the crystals are large, the fudge develops a crumbly, dry, or even coarse texture.

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).

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.

Brush the sides of the pan with a wet brush at the beginning of cooking to dissolve sugar crystals stuck to the sides. Never stir the mixture during cooking or sugar could crystallize again. The mixture may seize and become grainy. Use a candy thermometer or conduct a cold water test to check if the fudge is done.

Fudge typically contains more sugar than chocolate, so it may not be the best choice for those looking to limit their sugar intake. On the other hand, dark chocolate is a good source of antioxidants and can provide health benefits when consumed in moderation.

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.”

What is the science behind candy-making? ›

Heating up the solution forces the sucrose molecules to break up and caramelize. But when we do that, the sugar molecules really want to crystallize back into their solid form. Candy-makers use that crystallization process, and some strategic interference, to create the candies that we know and love.

The Science of Fudge: How Fudge Is Made

Once cooled to 122° F, the syrup is stirred and scraped, forming many crystals at once. Continued stirring helps the sugar molecules spread among and bind to the crystal seeds. This helps keep the crystals small and creates the fudge's milky texture.

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.

A temperature of 112°C to 114°C (234°F to 237°F) must be maintained. This will ensure the fudge has the ideal concentration of water and sugar. Fudge is difficult to make. Don't rely on recipes that tell you to boil the fudge mixture for a specific amount of time.

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.

Cream of tartar is used in caramel sauces and fudge to help prevent the sugar from crystallizing while cooking. It also prevents cooling sugars from forming brittle crystals, this is why it's the secret ingredient in snickerdoodles!

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.

As you stir the fudge, many crystals form at once, and the stirring helps the sucrose molecules bind to one another and start forming small crystals.

Beating the mixture encourages the formation of small sugar crystals, which leads to the crumbly texture. The crystals may not be noticeable in themselves but the fudge mixture will thicken and turn from shiny to matte in appearance.