Hollow Macaron Reasons and Fixes
One of the most asked questions in the macarons baking world is definitely “Why are Macarons Hollow?”. Unfortunately, it is a very common problem and can happen to anyone from a beginner to a professional baker.
There can be a lot of reasons why macarons are hollow – it can be wrong macaronage, wrong oven temperature, too humid weather, overmixing or undermixing the batter and the list goes on and on.
When I started baking macarons around ten years ago, macarons were not that popular. I watched a lot of YouTube videos and read plenty of recipes before I made the first try to bake them.
I had no idea what a hollow macaron was. Step by step I got smarter in this world and now I would love to share the knowledge I have learned during this long journey.
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Definition of hollow macaron
What is a hollow macaron? A hollow macaron means that the macaron’s shell is partly empty inside. In that case, the macaron’s shell is not completely full and fluffy inside as it should be. Hollow macarons can look perfect on the outside and taste the same as non-hollow macarons.
For many people, it does not matter, because the appearance outside is still looking good. So what is the problem here?
When biting the hollow macaron at room temperature, you probably won’t even notice the air pockets because the macaron shell and filling are soft and will lose the air while pressing them together.
Also, people who don’t know much about the macaron world probably have no idea about this common problem and enjoy their macarons either way. But as you are here reading this post, you probably are not a basic macaron lover, you want to know more and resolve the hollow problem.
Seeing your macarons turn out perfect outside but hollow inside can be very frustrating. Especially when you have tried so many times and won’t understand why it keeps happening.
Remember – macarons are very tricky. There is a reason why these little cute cookie-like sweets are one of the most difficult desserts to make. Don’t give up even if you want to do so. It took me several years to do a lot of research and trial-and-error experimenting to get my macarons perfect.
Main reasons for hollow macarons
Wrong temperature
Every oven is different so it is very important to know yours. This is also the reason why I can’t say what is the only right temperature for baking macarons. It depends on what macaron baking method you are using as well. Is it the Italian, French, or Swiss method – you should always follow the recipe correctly and make changes depending on your oven if needed.
If the wrong temperature is the reason for the hollow macarons then in most cases the temperature is too low – macaron batter does not have enough time to bake and dry in the oven.
It can result in a raw, wet, and heavy batter inside the shell that collapses to the shell’s bottom and causes the emptiness in the upper side of the shell. When this happens, the macaron won’t taste as good as it should. It can break very easily when touched and overall – it is not perfect.
When taking your macarons out of the oven, they should not move while gently pushing them with your finger. If they wiggle, put them back in the oven, because they are for sure underbaked.
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Overmixing
Overmixing is the most common mistake while making macarons. Mixing the macaron batter is the trickiest part of the macaron-making process. You need to be very gentle and patient. It is better to do it slowly to avoid air getting into the batter.
Mix the batter gently with a silicone spatula and do not forget to scratch the bottom of the bowl to reach all of the dough. Gently rub the batter to the edge of the bowl to get rid of the lumps.
The GIF below shows mixing a lot faster than it should be in a real-life scenario (it is just an example to show how to make the movement).
There is a rule in macarons world that the batter is ready when it flows down the spatula like lava and you can write the number 8 without the batter breaking. Once you can do that, stop mixing immediately to avoid your batter getting too runny. There is no way to make the overmixed batter thicker again so be very careful.
Undermixing
When the batter is undermixed then you will notice it at least in the piping process. Undermixed batter is thicker and won’t flow from the spatula like lava.
Even when you miss the lava-flowing step you will notice your piped macarons batter probably is not smooth and has little tips on them. You can save undermixed batter that is not piped yet – put it back into the bowl and slowly mix a little more.
Not sure if the batter is ready for piping? I have made a detailed blog post about macaronage. You will find everything about how to correctly mix the macaron batter from here What Is Macaronage? (Secret Macaron Batter Folding Technique).
Unstable meringue
If your macarons end up hollow, it could be because your meringue was not prepared right. Meringue is one of the most important aspects in the macaron making progress.
There are a few things you can do wrong while making the meringue that makes it unstable and causes the hollow macarons. In both overmixing and undermixing the meringue can cause hollows in your macarons.
An unstable meringue can be caused by a lot of different things such as using a mixing bowl that is greasy, using a plastic bowl instead of glass- or stainless steel, and using egg whites that are frozen.
Too long resting time
If you leave macarons to rest for too long before the oven, it can cause hollow macarons because the meringue will lose its stability over time. This can happen when you want to make a lot of macarons in the same oven and some of the macarons must wait in the queue before getting into the oven.
In that case, one part of your macarons have to wait a lot longer than others to get into the oven. It is better to bake fewer macarons at the same time when you only have one oven to use.
Wrong oven mode
Keep in mind that using different oven modes can make a huge difference in your baking. I personally like to bake my macarons with a fan mode using the Italian method for perfect macarons. Keep in mind that fan mode adds around 68°F (20°C) to adjusted heat.
Mixing too fast
Mixing your macaron batter too fast can also make your macarons hollow inside. I highly recommend folding your macaron batter very gently and slowly. Mixing too fast can cause hollow macarons because too much air gets into the dough.
Slow mixing is also good because thanks to that you will have better control over the batter and probably won’t overmix it.
Food coloring
The best food coloring for macarons is different kinds of gel-based food coloring. Overdosing food color can make the batter too runny and this can be the reason your macarons turn out hollow.
I highly suggest you take a look at my in-depth post about the best food coloring for macarons as it gives a lot of good tips on how to avoid failures.
Weather
Weather plays a huge role in your macarons making success. Humid and rainy weather can ruin your macarons as the macaron batter does not like humidity.
In case you are living in a humid climate there are a few things you can do to make your kitchen less humid: close the windows and use an air conditioner, dehumidifier, or kitchen cube.
Air bubbles
It is important to get rid of the air bubbles after piping the macaron batter to the baking sheet or silicone baking mat. After piping the macaron batter, you will probably notice a few air bubbles popping out. Gently fix the bubbles and holes using a toothpick.
If bubbles keep coming, again and again, I recommend tapping the tray on the bottom after piping the macarons.
To do that, slide the silicone mat or baking sheet onto the baking tray (or to make it easier, put it on the tray before piping the batter on it). Once piped, knock the tray against the kitchen cabinet or table. You will see the little air bubbles popping out after that.
Can you fix a hollow macaron?
Sometimes it is possible to save the hollow macarons – it just takes a little time. You can put the filling between the shells and make the macarons like you normally do.
Store the macarons in a closed container in the fridge overnight for 24 hours. Later when biting or cutting the macaron you may see that there are no air pockets or hollows inside.
The filling you put between macaron shells slowly presses on the shell’s bottom and makes the hollow “disappear”. It can save the hollow macaron but it does not resolve the problem.
As said previously – the filling pushes to the hollows and makes the air disappear. You can also press the shells yourself.
Take the shell and gently press the bottom of it with your finger. Pipe the filling and you’re done – you now have non-hollow macarons. It doesn’t solve the actual issue but a lot of bakers do that to visually solve the hollow shell problem.
When is the right time to investigate the hollow macarons problem?
Deal with the hollow macaron shell problem when your macarons are perfect otherwise. Perfect macaron is smooth and shiny on the top, has beautiful even feet, and is perfectly round-shaped.
Why shouldn’t you investigate it immediately? Try to fix other problems first because solving these can also solve the hollow problem. When something else is wrong with your macarons it can also be the reason for hollow macarons.
If you already can bake perfect-looking macarons then good for you – you know how to bake one of the most complicated desserts in the world and that is a huge success! Now is a good time to explore further the world of macarons and make them 100% perfect from start to finish.
Enjoy your macarons!
Belli xx