Peanut brittle is a type of candy that is made by placing peanuts, spices and sometimes other ingredients into a mixture of heated sugar and water and then allowing the mixture to cool on a flat surface. Once the brittle has cooled, the sheet of hard sugar and peanuts is broken into small pieces so it can be more easily stored and eaten. Some recipes for peanut brittle include other ingredients, such as vanilla, peanut butter, cinnamon, nutmeg or, occasionally, other types of nuts. Although there are only a few basic ingredients needed to make peanut brittle, the process of heating the sugar and water together requires some attention and usually a candy thermometer for precise measurements to ensure that it forms into a hard candy when cooled.
The texture of peanut brittle comes from water and sugar that is heated to a temperature known as the hard crack stage, after which it will cool into a hard, almost glass-like form. In many instances, corn syrup is added to the sugar and water mixture to prevent sugar crystals from forming and ruining the final texture of the brittle. After the mixture has reached a high enough temperature, it is removed from the heat.
Peanuts and vanilla are added to the brittle at this stage. If peanut butter is incorporated into the hot mixture, it will melt and cause the brittle to take on a peanut-like opaque color as opposed to the translucent golden color that plain sugar would have. Baking soda, butter and any other remaining ingredients then are stirred into the mixture and the hot peanut brittle is poured onto a flat surface so it can cool and harden.
Once on the flat surface, the baking soda that was added will cause the brittle to start to rise slightly, creating small gas bubbles inside so the hard candy is not too hard to eat or break. Some recipes call for the brittle to be kneaded or stretched as it is cooling to help develop the texture and distribute the peanuts, although this usually is not necessary. After the peanut brittle has cooled completely, it is ready to be broken.
The sheet of peanut brittle that results usually is broken into smaller pieces so it can be more conveniently eaten, packaged and stored. This can be done by breaking off pieces one by one, or by using a hammer or other utensil to shatter the sheet. Depending on several factors, peanut brittle that is stored in an airtight container or in a refrigerator can stay fresh for several weeks, although high levels of moisture or heat eventually will cause it to develop a stale taste and off texture.