Macaron Science 101

As a food scientist, the area nearest and dearest to my heart is baking and pastries. I learned about baking from my mother and grandmother growing up, and it even inspired my interest in the field many years later. My birthday is right around the corner, so what better way to celebrate than learning to make macarons! I have looked forward to this workshop for weeks and can’t wait to share the experience with you!

First, let’s start with a fun fact. Macarons actually aren’t French, they were invented in Italy! However, we can credit the French with refining the macaron recipe into the elegant, chewy, sandwich-cookie we know today.  The original Italian version was more of a traditional, crunchy meringue that was eaten on its own.

See those bubbly edges? Those are called the feet!

While macarons may be composed of simple ingredients, they are anything but simple to make. These beauties are extremely finicky and well-known for the trouble they give pastry chefs in the kitchen. Anything from the weather to the oven to your meringue folding technique can cause bumpy, hollow, flat, or uneven cookie shells. But, why? Why are these cookies so different from say, chocolate chip? To compare the ingredients and  processing techniques of chocolate chip cookies, check out my earlier post The (Food) Science of Chocolate Chip Cookies 🍪

First up, ingredients. The recipe I learned today is a little different than you may traditionally find.  Macarons are composed of almond flour, powdered sugar, egg white, granulated sugar, and water*. That’s it! Ratios are very important in any type of baking, so be sure to measure carefully and accurately to ensure the reactions can take place properly. Below is an example of a typical macaron recipe and an explanation of ingredient functionality. Many chefs have adapted and tweaked traditional recipes into what works best for them.

The chef has tweaked the recipe to be more fool-proof and easy to make ahead of time by adding cornstarch. This ingredient is used to draw out moisture and help to avoid humidity in the air. This helps keep the macarons moist.

Ingredients Function
Almond Flour Protein, structure, texture, flavor
Powdered Sugar Sweetness, texture, bulk
Egg White Moisture, structure, emulsification, meringue
Granulated Sugar Sweetness, meringue structure
Water Viscosity of batter

Now for the process, the hardest part. The information presented here is my learnings and scientific adaptation from the macaron class at Cooking at Millie’s in Louisville, KY.


The first step is to create the meringue. Meringues are such a fun science all on their own! This treat is a foam, which is a gas in liquid colloidal dispersion, which is similar to an emulsion. This is just a fancy word for a suspension. The infographic below helps to visualize what is going on inside the meringue.

Meringues are foams are colloidal dispersions

Egg whites and sugar are mixed by hand (literally) over a double boiler until the sugar has dissolved and the mixture is no longer grainy. Be sure not to cook the egg in the process, though. Next up, whip it! You will need to whip until the meringue double in size, is bright white, and shiny. Sugar is to thank for the beautiful gloss and stable structure.  To test to make sure it’s ready, look for stiff peaks. Pull your mixer out and allow the excess to drip off. Flip over the mixer and if the strands of meringue stick straight up, like icicles, it’s ready! If not, keep mixing. Any flavorings or color should be added at the end of this step.


WARNING! Be careful not to overmix, this would overwork the proteins and cause water to leach out of the matrix you just created. If water is not held in the matrix, it will evaporate in the oven and cause cracks in your beautiful cookie shells. On the other hand, undermixing means you will not create enough of a network (e.g., structure) and your shells will be flat.

ALSO: do not allow ANY egg yolk in your egg whites. The fat in the yolk will interrupt the protein matrix, as well. Along the same lines, it’s important to ensure your cooking utensils are spotless, and no residues have been left behind.


Now that the meringue is ready, it’s time to fold into the dry ingredients. Be sure all dry ingredients are sifted to ensure your shells are smooth. This is called “macaronage.” Pour the meringue into the center of the dry ingredients and begin to mix aggressively in a “painting” motion. At this stage, we want to get out any large air bubbles in the batter. Add a few drops of water as needed to thin out the batter. After incorporation, fold from the bottom up and over. Be sure to use a clean rubber spatula, and constantly scrape off on the edges to continue incorporating. Hardened streaks can cause bumps on the finished cookies.

Mix until the batter flows like lava. It should not be too runny. When you pick up the batter, it should flow for about 3 seconds off the spatula before “breaking.” Add more water if needed. This step is critical for creating smooth and full shells.


Next, it’s time to pipe! Hold the bag straight up and apply constant pressure. You can use macaron stencils to help with placement. As you can see, it’s a little more challenging than you might expect for your first time!

After piping, you must get any last air bubble out. You can do this by tapping the bottom of the cookie sheet and dropping it forcefully onto the countertop. Don’t let the shells sit too long, put them in right away. Allowing them to sit may cause them to become lopsided or not rise.


Bake time! We used a 300-degree oven for roughly 16 minutes. Rotate the pan halfway through. Keep an eye on the cookies in the oven. Times can vary by oven and adding things like flavor or color can affect bake time. The cookie should easily peel off the parchment paper and should not be hollow. IF the shells are hollow, they are not done!

What happens during the baking process? Remember the air stabilized in the meringue by proteins? This air allows the cookie to rise and also creates the “feet” on the bottom. Again, this highlights the importance of the meringue stage.

Pay attention to your oven temperature, as well. All ovens run a little differently. Low oven temperatures can prevent feet from forming, while high temperatures can cause the feet to become too large with little rise in the shell.


Tip: See how my shells are a little uneven? This could be due to not piping directly above the pan or not getting enough air out the batter during the macaronnage stage.


Fill one cookie shell with ganache, icing, or jam, top with another cookie, and enjoy! There’s nothing quite like a delicious macaron!

These delicious macarons are filled with lemon coconut buttercream, raspberry jam, and chocolate ganache fillings!

This slideshow requires JavaScript.


Storage. Store the cookies in an airtight container in the fridge to keep them from drying out. You can also freeze the shells for later if you place them in an airtight container and layer with parchment paper. The cookies can last about a month in the freezer.


A big thank you to Chef Patricia and Cooking at Millie’s for a great pastry experience! If you’re in the Louisville area, be sure to check them out! 🙂

* Macaron recipe and method credit: Chef Patricia Kelley @ Wiltshire Pantry

You may also like


  1. Your problem with uneven shells is due to the fact you didn’t create a proper macaronage. Adding water to the batter is a very bad idea, it tricks you into thinking the batter is at the correct consistency. NEVER add water to macaron batter – the only time this is an acceptable practice if when making an Italian Meringue based macaron.

    1. Hello and thank you for your comment! This recipe uses the Swiss meringue method of heating sugar and egg whites together. This class was a learning experience for me and my technique certainly needs some practice! I will keep your comment in mind for future recipes!

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: