How To Fix Hollow Macarons

Whether you've been baking macarons for a while or you're a beginner, it's inevitable that at some point you have baked hollow macarons.

Hollow macaron is a term used to describe an air pocket that is present in the shell when you crack it open.

As you probably know, an ideal macaron should have a full, slightly chewy interior. I'll walk you through all of the equipment, technique, and ingredient related issues that could be causing your macarons to be hollow.

Fixing hollow macarons should be last on your list. First, be sure you've fixed any issues with cracked shells, wrinkly tops, small or ruffled feet, and flat shells. Then, you can move on to fine-tuning your technique to achieve full shells.

As always, remember that it takes some trial and error to bake macarons at home. Don't give up on your first or second attempt, keep going!

You can always refer to my macaron troubleshooting video, or leave a comment below, and I'll do my best to help you out.

Here is an equipment related issue that could be causing the macarons to be hollow:

1. Oven temperature is too hot/too cool: Oven temperature is one of the most important pieces of equipment you'll use for baking macarons. A small change in temperature, even by just 5°F (3°C), can make a big difference in your macaron shells.

An oven that's too hot will cook the outside of the shells quickly without allowing the inside enough time to cook and properly rise.

While an oven that's too cold won't allow the macarons to completely dry or bake long enough to fully rise.

To avoid hollow macarons you'll need to experiment with your oven temperature. You can read more about my experiments with finding the best oven temperature for macarons if you're interested. Here's a short explanation of what I did.

If you're wondering how to fix hollow macaron shells, you have to pay close attention to your techniques. It's important to learn to master these techniques if you want perfect macarons.

Here are some techniques you could be getting wrong:

1. Under or over whipped meringue: Whipping the meringue to stiff peaks (not over or under) is one of the most crucial steps when making macarons.

Both under-whipped and over-whipped meringue (no matter what type of meringue you use) can result in hollow macaron shells. This is because the meringue needs to have the proper structure in order to rise in the oven.

A weak meringue will not be strong enough to withstand the heat of the oven when baked, causing a hollow shell. Alternatively, meringue that has been over-whipped won't have enough air incorporated to properly expand in the oven.

In order to achieve stiff peaks, you need to learn the visual cues you can use to know the meringue has whipped to stiff peaks:

• You'll notice the meringue starts to ball up inside the whisk while it's mixing.
• Pull the whisk out of the mixer. A stiff peak should stand straight up (no curl at the tip).
• You can see pointy off-shoots of egg whites on the whisk when you pull it out of the mixer.
• You can fully flip the bowl over and nothing moves or falls out.
• The meringue feels sturdy (not flimsy).
• The egg whites hold the indentation that the whisk makes as it's whipping.

It typically takes around 8 - 10 minutes to reach stiff peaks, depending on your mixer and the speed. I use a KitchenAid mixer on speed 7.

Additionally, if you're making French (common) meringue, make sure to slowly add the granulated sugar during the whipping process. This allows the sugar crystals time to dissolve so they don't weigh down the egg whites.

If the sugar is added too quickly, it can affect the final structure, resulting in an under-whipped and weak meringue.

As for over whipped meringue, this is overly thick, looks dull, and can become clumpy. Over whipped meringue will also be very hard to macaronage.

4. Underbaked shells: If you are underbaking your macaron shells, they may not be fully rising, resulting in hollow macarons.

Not only is it important to find a good oven temperature, but it's also important to ensure your macarons are done baking. Here are some ways to check for doneness:

• The feet and the edge of the macarons feel firm when you gently touch them.
• It feels like you could forcibly lift the macaron shell off the parchment paper if you needed to (don't actually do this, just use it as a test).
• If you touch the shell and it wiggles, is still sticky, or is wet, you know the macarons need longer to bake.

5. Macarons haven't matured in the refrigerator: Most macaron bakers suggest maturing the macarons with their filling in the refrigerator for 24 hours to allow the flavors to marry together and the macaron shell to slightly soften.

This technique can, at times, fix some minor issues with hollow shells.

If you have very large air pockets, maturing the macaron shells will not fix this issue. However, minor air holes will oftentimes fill in once they have time to mature in the refrigerator.

Not all macaron fillings last well when stored in the refrigerator, especially jam and curd. Be sure to refer to the macaron storage instructions for each type of filling you're using.

Most of the ingredient-related issues you'll run into with hollow macaron shells involve egg whites:

1. Too much egg white: Whether you're developing a recipe or using someone else's well-tested macaron recipe, you need to pay special attention to the egg whites.

Egg whites are made up mostly of water. In fact, 90% of the egg white is water while only 10% is protein.

If you're developing a recipe and you know you are correctly executing all of the other possible problems listed in this article, you're likely experiencing an issue with too much liquid from your egg whites.

Here are some ways to mitigate this issue:

• Reformulate your ratio. This could either include reducing the amount of egg whites or increasing the dry ingredients.
• Age your egg whites to reduce the amount of water in them.
  
  To age egg whites, you'll separate the egg whites from the yolks 2 - 5 days before baking the macarons. Place the egg whites in a container covered with plastic wrap.
  
  Poke a couple of holes in the plastic wrap, and place the eggs back in the refrigerator. This allows some of the water to evaporate in the fridge.
  
  Once you're ready to bake, allow the egg whites to come to room temperature before whipping them into meringue.
• Alternatively, use egg white powder to help reinforce the protein structure. Usually, you'll want to use about ¼ teaspoon of egg white powder for every 1 egg white.

• Oven temperature is one of the most common reasons for failed macarons. I'd suggest investing in an oven thermometer to ensure your oven is properly heating.
• Only bake one tray of macarons at a time. This can also help you pinpoint any issues you may be having related to oven temperature.
• Don't forget to mature your macarons with the filling in the refrigerator for 24 hours to help with minor air pockets (hollows). I'd only suggest doing this if you're using a buttercream filling or ganache.
• If you're having trouble with under or over whipped meringue, you should consider using a different type of meringue for your macarons. Swiss and Italian meringue macarons are known for being more stable.
• Don't be tempted to throw away macarons with hollows. These macarons are still perfectly edible and should be enjoyed!