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.

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.

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.

Heating the syrup to a high temperature and then allowing it to cool, undisturbed, produces a supersaturated solution—this means that the solution contains more sugar molecules than would normally be possible at room temperature.

Beating after cooling

This fudge cooled until it reached 43 to 45 °C (109 to 113 °F) before being beaten. It has a smooth and creamy texture, just how we like it. Here's why: syrup becomes quite viscous (thick) while cooling, and this slows the movement of sugar molecules.

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.

Gummy candy is made of the sugars glucose and sucrose. It also contains the thickeners starch and gelatin. They are polymers, or large molecules made up of repeating units. When the sugars and thickeners are combined, bonds form between the thickeners, trapping the sugars between them.

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.

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 the heck is fudge? ›

Fudge is a type of confection that is made by mixing sugar, butter and milk. It has its origins in the 19th century United States, and was popular in the women's colleges of the time.

Fudge is a dense, rich confection typically made with sugar, milk or cream, butter and chocolate or other flavorings. The base for fudge is boiled until it reaches the soft-ball stage (135 to 140 degrees F), then stirred or beaten as it cools to minimize the formation of sugar crystals.

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.

In his book On Food and Cooking, food scientist Harold McGee writes, “A metal spoon can induce crystallization by conducting heat away from local areas of the syrup, cooling them and so leaving them supersaturated [causing crystallization].” He recommends using a wooden spoon, which doesn't conduct heat.

OPTION 1) Depending on how runny it is, you can either use it as a frosting for cakes, or a sauce for ice-cream. OPTION 2) Freeze it overnight. Cut it into squares. Cover each square thickly in melted chocolate, ensuring no part of the fudge is exposed.

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).

Beating fudge when it's still over heat creates sugar crystals, aka the grittiness you feel in the fudge. Instead, wait to pick up the spoon (our Test Kitchen loves using wooden spoons) until the fudge drops to between 110 and 113°F, about 15 minutes.

Corn syrup was an interfering agent in fondant, fudge, hard candies, peanut brittle, and toffee. It prevented the sucrose molecules from crystallizing and gave the finished product a smoother texture and mouthfeel.

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.