Every year, my mother used to make chocolate fudge to give to friends and family for the holidays. It was rich, dense, creamy, and oh so chocolatey—most of the time. Occasionally, even though she used the same recipe, the fudge would turn out grainy. Why this happened was always a mystery. Fast-forward to the present: Determined to solve the “grainy” puzzle, I put my food science knowledge to work. What I found were not only answers but also a foolproof method for amazing fudge.
Making melt-in-your-mouth chocolate fudge is simple: You boil sugar, heavy cream, and chocolate, let the mixture cool, and then beat it to the right consistency. As the mixture boils, the sugar crystals dissolve, and the sugar concentration gradually increases. Then, once beating starts, the sugar begins to recrystallize. If the crystals stay small, the result is a smooth fudge. But if larger crystals form, the fudge will be grainy. Because large crystals can form at any time during fudge making, you need to be vigilant. Here’s what to do every step of the way for perfect results.
Use corn syrup and butter Both interfere with sugar crystallization, so adding them to the fudge prevents the crystals from growing too large. Butter should be added only after the boiling is done. If added before boiling, it coats the crystals and keeps them from dissolving, resulting in grainy fudge.
Clean the pan sides It’s important to keep the boiling mixture from coming in contact with sugar crystals on the sides of the pan; otherwise, the sugar will start to recrystallize too soon, causing large crystals to form. To prevent this, cover the pot with a lid for two minutes after it starts boiling—the steam will wash the crystals down the sides.
Bring it to the right temperature Boiling the mixture to 236°F to 238°F (known as the soft-ball stage) results in the correct concentration of sugar, so the fudge sets up to the proper firmness after beating. Fudge boiled below this temperature is too soft to hold its shape, and fudge boiled above this point becomes too firm.
Don’t stir the fudge Shaking or stirring the fudge mixture while it’s boiling or cooling causes premature crystal growth. If the crystals form too early, they continue to grow and become too large.
Let it cool Start beating the fudge only when it has cooled down to 110°F. It will be glossy and dark brown. If it’s hotter the crystals will form too fast and the fudge will be grainy. If the fudge is too cool it will set up and be difficult to beat.
Know when to stop beating Beat the fudge vigorously to form many small crystals and create a smooth texture; stop beating when it turns a lighter brown and becomes more opaque, and when the ripples made by the beaters hold their shape long enough to briefly expose the bottom of the pan.