These little cookies are much more complex than what meets the eye. The chemistry involved in making a single macaron is quite mind blowing.

A macaron (also known in Australia as ‘macaroon’) is a sweet prepared in many regions of France. Its name is derived from the italian word “maccarone” or “maccherone” which evokes the crushing or beating of the almond paste which constitues its main ingredient.

In Nancy, Lorraine, macarons have been part of the local history since the time of the French Revolution (18th C) when two nuns, the “Sœurs Macarons” (Sisters Marguerite and Marie-Elisabeth), created the famous delicacy seeking asylum in Nancy during the French Revolution, baked and sold the macaron cookies which they made for both nutritional and commercial purposes (baked goods, honey, and other such food products were a source of revenue for most monastic orders, which had very limited ways of making money). These macarons were served as it was, without and added flavours or fillings.

It wasn’t until the 1830s that macarons began to be served two-by-two with the addition of jams, liqueurs, and spices. The macaron as it is known today, composed of two almond meringue discs filled with a layer of buttercream, jam, or ganache filling, was originally called the “Gerbet” or the “Paris macaron.” Pierre Desfontaines of the French pâtisserie Ladurée has sometimes been credited with its creation in the early part of the 20th century, but another baker, Claude Gerbet, also claims to have invented it. French macaron bakeries became trendy in North America in the 2010s.

Last, but not least, the macaron has even a special day of the year – March, the 20th – was introduced in 2005 by Pierre Hermé, another famous French confectionary house. ‘Macaron Day’ is celebrated throughout the world, and participating macaron shops offer free samples to their customers. Save the date and go eat some delicious sweets!

What is the science behind making macarons?

  • Folding the batter to a certain stiffness, getting a precise ratio of egg white to almond flour to sugar, leaving the shells out to harden, getting the “feet” to rise, aging the egg whites beforehand – how can these steps be explained in terms of chemistry
  • First, the easiest: leaving the egg whites out to age. This has the effect of getting rid of a lot of the moisture in the egg whites, which strengthens the protein in them and ultimately makes for a stronger, higher-quality meringue.
    Bitter Chocolate Macarons
  • There’s supposedly a “perfect” sugar-to-almond-to-meringue ratio but I tend to follow whatever my recipe says (it usually ends up being equal parts almond flour and confectioners sugar, and then a meringue with a little more granulated sugar than egg white). And this is for the same reason you use specific quantities of whatever when you bake — enough flour and sugar to form a solid cookie but enough meringue for it to be ribbon-y and airy. Too much almond flour can easily result in burned, stiff cookies. Too much meringue can lead to air pockets. Too much sugar can lead to the sugar burning, while not enough sugar can weaken the meringue and keep the ‘pied’ from forming properly.
  • You don’t want a meringue that’s over-beaten (too much air, which can result in cracking and warped feet) or underbeaten (too flat, causing stiff and/or peaky shells). Moisture in the air or lack thereof can also affect the meringue. If it’s humid, it can take a longer time for the meringue to form, and if it’s dry, the meringue can form very quickly; it’s at a risk of being over-beaten.
  • Folding the batter is, for me, the most delicate process. The point is to “deflate” the meringue somewhat, but to still leave some air in the batter. If you underfold it, the cookies can be stiff and peaked. If you overdo it, the meringue gets too “flat” and the cookies spread into shapeless goo.
  •  The final step before letting the shells dry out is banging the pan on the counter a few times. This serves the purpose of getting out any excess air from the shells. This, plus letting them dry out, is what helps the cookies form feet. The dry shell and lack of excess air, as I understand it, keep the cookie from “rising” in the oven — the batter beneath the sturdy shell has nowhere to go, so the batter is forced to spread outward, which is how you get the foot, or pied.
  •  The baking is also tricky because at that point it’s out of your control. The trick is just troubleshooting, but I find that the important thing is even heat distribution. You can always increase or lower the temperature, and every oven is different.

It’s all about the chemistry of the egg white proteins, the ratio of ingredients working together, the drying-out of the shells and the oven temperature, and the physics of proper air distribution.

It all comes down to science. You need to make sure you start adding the sugar no longer than 25 seconds of beating the egg whites … just until they get a bit foamy. This will immediately increase the viscosity or thickness of the whites, making it more difficult for air bubbles to form.

The thick egg whites are more elastic when all that water-binding sugar is added to them before the proteins get the chance to form a stiff foam, so it’s more like a soupy, gooey mess.

Also, when sugar is added near the beginning of the whipping stage, it gets very selfish. Sugar loves to bind water, so it hogs all of the water in the egg whites, leaving the egg proteins with less of a medium to move around in. This slows them down so that they can’t arrange themselves at the interface between air and water as easily to form large air bubbles. So, instead they end up forming very tiny air bubbles, which results in a more stable foam, that has enough elasticity to hold up during mixing and piping.

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