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.

Confectionery experiments have shown that the ideal cooking temperature for fudge is around 114 to 115 °C (237 to 239 °F). The cooking is intended to evaporate a part of the liquid and concentrate the sugar. The temperature of the cream/sugar mixture (called syrup) rises as water evaporates.

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.

Cook the mixture over medium-low heat, without stirring, until the thermometer registers 234 degrees, about 20 to 25 minutes. The mixture should boil at a moderate, steady rate over the entire surface. While the fudge is cooking, prepare the baking pan.

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.

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).

How do you fix fudge that is too soft? Bring the fudge back to a boil with 1–2 US tbsp (15–30 ml) of cream. If your fudge is soft or runny, it probably didn't come up to a high enough temperature while it was cooking. Put it back into the saucepan and add 1–2 US tbsp (15–30 ml) of 35% fat whipping cream.

The main reason is that your Fudge has not reached the optimum temperature. If your mixture only reaches 110 or 112 degrees Celsius it will always be soft. That's why we recommend investing in a sugar thermometer. Another reason your Fudge is not setting is that the ratio of liquid to sugar is too high.

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.

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

If the sugar crystals are not properly dissolved before cooling, they can create a gritty texture. To avoid this, ensure that you stir the fudge mixture consistently and remove any sugar crystals that form on the sides of the pan using a wet pastry brush.

Fudge is best stored at room temperature for 2 to 3 weeks wrapped up in its original wax paper. NEVER REFRIGERATE your fudge as this will draw out the moisture and leave you with dry, crumbly fudge.

The cold-water test for soft ball stage is this: Fill a cup with very cold water. Spoon a small amount of the boiling candy mixture into the cold water. If the syrup forms a soft ball in the water that flattens when removed, it is at soft-ball stage.

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.

The main reason is that your Fudge has not reached the optimum temperature. If your mixture only reaches 110 or 112 degrees Celsius it will always be soft. That's why we recommend investing in a sugar thermometer. Another reason your Fudge is not setting is that the ratio of liquid to sugar is too high.

Fudge usually behaves this way when it's not cooked to a high enough temperature (due to oversight or a faulty candy thermometer). If your fudge is tough, hard, or grainy, then you may have made one of several mistakes: You may have overcooked it, beaten it too long, or neglected to cool it to the proper temperature.

There are two main reasons. First, we use ingredients not prone to melting. Specifically, we use heavy cream instead of butter. Second, we slice our fudge while still warm so that each slice forms a firm outer shell.