Science of Cooking: Fudge Recipe: What’s Going On? (2024)

FAQs

What is the science behind making fudge? ›

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.

Fudge Didn't Set

If your fudge turned out super sticky, or it didn't set as it cooled, it probably never got hot enough. This mistake is super easy to avoid if you use a candy thermometer and cook the fudge to the temperature specified in the recipe (usually between 234 and 239°F).

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.

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!

Avoid too much stirring while you are heating the fudge since this agitates the sugar and causes it to clump into sugar crystals again. Once it's reached 237 F, allow the fudge to cool to 110 F, and don't stir the fudge at all while it's cooling. Less is more in this case.

Don't stir!

Once the fudge reaches soft-ball stage on the candy thermometer, remove from the heat and let the temperature drop to 110°F. Keep that spoon or spatula out of the pot until this happens. If you stir too early in the process, you'll make the sugar crystals too big and end up with grainy fudge.

Too cooked

At this temperature, the sugar is too concentrated and there is not enough water left to form syrup around sugar crystals. 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.)

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.

Options for what you can do with your unset fudge:

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.

What consistency should fudge be before it sets? ›

You know it's ready when a small amount of the mixture dropped into a glass of cold water sets into a soft ball that you can lift out with a teaspoon and pinch between your fingers. Turn off the heat and keep stirring for 5 minutes or until the mix starts to thicken a little.

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.

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.

If your fudge has a texture like soft toffee, it could be due to overcooking, using too much sugar or butter, or not cooking it to the right temperature.

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).

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.

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.