Peanut brittle is an old-fashioned treat that many home cooks prepare for party snacks or gifts. The hard candy mixture must cool completely before you can break it into pieces. While many recipes tell you to cool the finished brittle overnight, peanut brittle takes approximately 15 to 30 minutes to cool, depending on how thick or thin you make it.
Brittle Cooling Basics
The secret to a crunchy brittle lies in the cooking process. If you don't cook the candy syrup until it reaches 305 degrees Fahrenheit, it won't harden no matter how long you cool it. A normal batch of peanut brittle poured into a buttered baking sheet will cool completely in about 30 minutes. At that point, you can hit the surface with a knife handle to crack the brittle, or simply lift up the pan a few inches and drop it onto the countertop. Place the cooling pan of brittle on a wire rack so air can circulate underneath it.
Thinner brittle cools more quickly. For faster cooling, pour the hot candy syrup mixture onto a couple of buttered baking sheets. Put on food-safe rubber gloves and, working quickly, stretch the still-pliable brittle into a thin layer. A pan of very thin brittle will cool in approximately 15 minutes.