Meringues

I love cookies! One of my favorite types of cookies is meringues. They’re sweet, crunchy, and melt in your mouth. To make them even tastier (in my opinion), you can add chocolate to give them an extra burst of flavor. What makes these cookies even better is that you can learn science while making them! I hope you enjoy these cookies as much as I do and learn something while making them.

What you need:

• 1 egg
• 1/4 teaspoon cream of tartar
• 1/3 sugar
• 1/2 teaspoon vanilla extract
• Optional: chocolate chips or Hershey’s kisses

Steps:

• Preheat the oven to 350 degrees Fahrenheit and line a baking sheet with parchment paper or a silicone liner.

• Separate the egg white and egg yolk of the egg. An easy way to do this is to crack the egg, leave the yolk sitting one half of the egg shell, and let the egg white fall off into a bowl. Keep pouring the egg yolk between the egg shelf halves until little white is left. Make sure there is no egg yolk in the egg white.

• Beat egg white until foamy using an electric mixer.

• Add the cream of tartar and beat until fluffy.
• Add the sugar about 1 tablespoon at a time while still beating.

• Add the vanilla extract and continue beating until the meringue is shiny. The meringue should have stick peaks when it is ready. A way to measure if it has stiff peaks is to pull the beater out of the meringue mixture, and look at the meringue mixture that it pulls up, or the “mountain.” The peak of the “mountain” will stay straight up if it has a stiff peak. Make sure not to over-beat the meringue.

• Drop the meringues by the tablespoonful onto the lined baking sheets or piped onto the sheets using a pastry bag, leaving a 1-inch space between each cookie.

• Optional: Place a Hershey’s kiss or 3-4 chocolate chips in the middle of each meringue.

• Smooth over the top of each meringue with the spoon or your finger.

• Place the baking sheet in the preheated oven and turn the oven off.
• Leave the cookies undisturbed in the oven for 2 hours.
• Remove from the oven to cool.
• Enjoy your tasty cookies!

How is science involved with making meringues?

Egg whites are 90 percent water and about 10 percent protein, with trace amounts of vitamins and minerals. Proteins are long chains of amino acids. When we beat the egg whites, we disrupt them, causing their proteins to denature and expand, taking up more space. This causes the the hydrophobic, or water-fearing, and hydrophilic, or water-loving, amino acids to be exposed. The hydrophilic amino acids scramble through the egg white to reach the water while the hydrophobic scramble away from the water. This incorporates air into the structure as the hydrophobic amino acids protect air to which they are attracted. They coat the air bubbles and link together with other molecules to form nets around the air molecules and prevent popping. Sugar helps more amino acids gather on the surface of the air bubbles, which creates stronger nets and leads to a more stable meringue. Stabilizers, such as cream of tartar, encourage the amino acids to bond together, making the meringue stronger and less likely to deflate. They donate positively-charged hydrogen ions to the egg white’s negatively-charged protein strands, neutralizing the meringue and slowing down the time it takes for the egg whites’ proteins to denature.

It is important to make sure no egg yolks are in the meringue because they contain fat. Excess fat will cause the bubbles will pop. If you over-beat your meringues, too many amino acids will join and form a super-tight net. The water in the meringue will be squeezed out, and the meringues will separate into a grainy solid and runny liquid.

Swartz, Isabella. “The Science Behind: Meringue.” Medium, Show Some STEMpathy, 12 Sept. 2017, medium.com/show-some-stempathy/the-science-behind-meringue-d48151a6acf9.