A Sweet Bite of Science: The Science behind the French Macaron (2024)

Jessica Trinh | Oct. 17, 2016

You scan the flavors of macarons at the counter — from almond to strawberry to lychee and even rosemary. You buy one and biting into it, you’re met with a sensation of varying textures: first crunchy, then chewy, then it melts in your mouth. In that moment, you pretend you’re in a French pâtisserie — better yet, France. After buying one, you realize it’s not enough and you buy another and another until you realize your wallet is empty — or your conscious is kicking in — and you leave, still hungry for more.

Photo Courtesy of Jessica Trinh

Macarons, a sweet almond-based confection notable for its smooth tops, ridged edges, and unique texture, have become all the rage in popular culture. However, the science behind them is a rather sensitive, finicky process that goes unbeknownst to many.

As complex as the flavors and textures are, it may surprise you to know that the cookie base is made from a simple concoction of confectioner’s sugar, almond flour, beaten egg whites, and granulated sugar — naturally gluten-free and fat free (!). The batter is dyed various colors and, once baked, sandwich a sweet filling of endless possibilities of flavors. Despite the simple ingredients, the technique behind making these sandwich cookies explains why the price tag is just so high.

In simplified terms, the science behind macarons heavily relies on a combination of the ratio of ingredients, basic protein structure of egg whites, the method in which ingredients are incorporated, and even the oven temperature.

Unlike traditional cookies, macarons are made from a meringue. Whereas most cookie batters are made of butter and flour, a meringue is made of egg whites and sugar, beaten into a delicate white cloud. However, the ratio of confectioner sugar to almond flour makes a difference in the meringue that is formed: too much of the almond flour produces a thicker meringue whereas too much confectioner sugar results in a thin meringue.

Beating egg whites, thereby denaturing its proteins, creates the meringue. In this process, the ball-shaped protein ovalbumin, which makes up 60–65% of the protein in the egg whites, begin unfolding. This forces the positively and negatively charged parts to form bonds and thus create a new network. Soon enough, the little foaming of egg whites becomes over four times its size, a glossy opaque white in color that closely resembles whipped cream.

As the egg whites are continually beaten, the proteins in the meringue form a soft peak. On the molecular level, the proteins have formed bonds with each other around the water droplets, which stabilize the water droplets. Once the soft peak forms, the addition of granulated sugar and continued beating of the mixture form stiff peaks. A helpful sign to know when this happens? Turn the bowl of egg whites upside down over your head and none of it should fall out!

Overbeating the egg whites, however, has its consequences. As the proteins continue forming bonds, the water molecules held within the protein bonds are forced out of the matrix. The effect is shown on the macaron shell: broken and cracked. Underbeating the egg whites has just as disastrous an effect on the shell as well, resulting in shells that are too flat and stiff.

Once the meringue has been made, beaten to the right texture and you may think all the hard work is done, right? Unfortunately not. Properly creating the meringue is only half the

Photos Courtesy of Jessica Trinh

battle. The next step is just as critical: mixing. In this stage, called the “macaronnage”, the meringue mixture is folded into the almond flour and confectioner sugar mixture. This folding technique is essential to the success of the macarons. The egg whites must be incorporated into the meringue by gently cutting into the mix with a rubber spatula, scraping the bottom of the bowl, then coming back up and over the top of the batter. The process is repeated over and over until the macaron batter is glossy and flows like lava. This folding technique makes all the difference in the texture of the macaron cookies: deflating the batter just the right amount ensures that once in the oven, the interior of the cookie is chewy and not hollow.

The batter is then piped onto either a parchment-lined baking sheet or a macaron pan and left to dry slightly before placing into the oven. Doing so enables the outer surface to harden slightly so that in the oven, air will escape from the bottom of the cookie as opposed to the top, which may create cracks on the surface.

Once in the oven, however, the fate of the macarons that has been so meticulously handled up until this point is largely out of our control. The oven may run hotter or lower than expected, and the uneven heat distribution will prevent the macarons from forming their characteristic ridge of bubbles around the base of the cookie called “feet” — the mark of a true macaron.

After the shells are removed from the oven and cooled, they may now be piped with a filling such as a buttercream, ganache, or jam. However, after all the hard work, the sweet confection cannot be eaten yet! Placing the macarons into the refrigerator is the key to allowing the shells to absorb the flavor of the filling.

Finally, after all of the painstaking work, the macarons are proudly placed in the glass cases of the pâtisserie, ready to be sold. The process is certainly daunting, but when done correctly, produces some of the best dainty cookies you’ll ever try. And so, the next time you try a macaron, you may have a newfound appreciation for the art and precision demanded from these French cookies.

Jessica Trinh is a freshman in Branford College. Contact her at jessica.trinh@yale.edu.

Featured Image courtesy of Jessica Trinh.