It’s Halloween. You’ve just finished the trick and it’s time to evaluate the payload. You likely have a favorite, whether it’s chocolate, peanut butter cups, those rubber bands with Nerds on them, or something else.
For some people, myself included, one piece stands out – the Snickers bar, especially if it’s full size. The combination of nougat, caramel and milk chocolate covered peanuts makes Snickers a popular dessert.
As a food engineer studying candy and ice cream at the University of Wisconsin-Madison, I now look at candy in a completely different way than I did as a kid. Back then, it was all about shoveling it in as fast as I could.
Now, as a scientist who has made a career out of studying and writing books about sweets, I have a very different view of sweets. I don’t mind sacrificing a part for the microscope or texture analyzer to better understand how all the components come together. I do not work for, own stock, or receive funding from Mars Wrigley, the company that makes Snickers bars. But in my work, I study the various components that make up many popular candies. Snickers has many of the most common elements you’ll find in your Halloween candy.
Let’s look at the elements of a Snickers bar as an example of candy science. As with almost anything, once you get down to it, each component is more complex than you might think.
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Airy nougat
Let’s start with the nougat. The nougat in a Snickers bar is a slightly fizzy candy with tiny sugar crystals scattered throughout.
One of the ingredients in nougat is egg white, a protein that helps stabilize the air bubbles that provide a light texture. Often, nougats like this are made by beating sugar and egg whites together. The egg whites coat the air bubbles created during the beating, which gives the nougat its fizzy texture.
A boiled sugar syrup is then slowly stirred into the egg white sugar mixture, after which a melted fat is added. Since fat can cause air bubbles to collapse, this step should be done last and very carefully.
The final ingredient added before cooling is powdered sugar to provide the seeds for crystallization of the sugar in the batch. The presence of small sugar crystals makes the nougat “short” – pull it between your fingers and it breaks cleanly without stretching.
Chewy caramel
On top of the nougat layer is a strip of chewy caramel. The chewiness of the caramel contrasts with the light and airy texture of the nougat, which provides contrast to every bite.
Caramel is different from other sweets because it contains a milk ingredient, such as cream or evaporated milk. During cooking, the milk proteins react with some of the sugars in a complex series of reactions called Maillard browning, which gives the brown color and flavor of caramel.
Browning Maillard starts with certain proteins and sugars. The end products of these reactions include melanoidins, which are brown coloring compounds, and a variety of flavors. The specific flavor molecules depend on the starting materials and conditions, such as temperature and water content.
Commercial caramel, like the one in the Snickers bar, is cooked to about 240-245 degrees Fahrenheit (115-118 degrees Celsius), to control the water content. Cook at too high a temperature and the caramel becomes too hard, but if the cooking temperature is too low, the caramel will run right out of the nougat. In a Snickers bar, the candy needs to be a little chewy so that the peanuts stick to it.
Chocolate coating
To make chocolate, raw cacao beans are harvested from cacao pods and then fermented for several days. After the fermented beans are dried, they are roasted to develop the chocolate flavor. As in caramel, the Maillard browning reaction is an important contributor to chocolate flavor.
The milk chocolate coating on the Snickers bar occurs through a process called enrobing. The bare bar, placed on a wire mesh conveyor, passes through a curtain of liquid tempered chocolate, covering all sides with a thin layer. Tempering the chocolate layer makes it shiny and gives it a well-defined snap.
The flow of tempered chocolate must be precisely controlled to give a layer of the desired thickness without leading to tails at the bottom of the candy bar.
Snickers bar
When done right, the result is a delicious Snickers bar, a popular Halloween – or anytime – treat.
With around 15 million bars made every day, getting every detail right requires a lot of scientific understanding and engineering precision.