french meringue experiment

The Science of Meringues: Egg Whites, Sugar & Heat

Every time we whip up some egg whites into a white, light, and airy foam we’re a little amazed. It’s pretty special how such a simple ingredient can hold on to so much air! Even more special, when you consider that chickens don’t really need that foaming ability to grow chicks out of their eggs.

These light and airy foams are powerhouses when it comes to holding on to air. Something that isn’t all that easy to do. So far the only other food ingredient that comes close is aquafaba.

There are tons of ways to let the airiness of an egg-white shine and see the science in action. But, the simplest one is by making it into a meringue. In meringues, sugar and egg white (and maybe some heat) work in tandem to create an array of foams that are even more stable and airy than those made with just egg whites. We’re going to dive into the science behind these foams to give you the tricks and tools to make even better meringues going forward.

What is a meringue?

Meringues are light, fluffy, edible foams, traditionally made from egg whites and sugar. Some are crisp, whereas others are soft and shiny. Some are aked, whereas others are ‘cooked’ and yet others receive no heat treatment at all. If no color is added, meringues are white(-ish).

You’ll find meringues in a range of foods, though most commonly in sweets/desserts. In some applications, you’ll eat the meringue as such but they’re also often used as a topping (on pie or eggnog), or as part of a dish (e.g. pavlova or in your chocolate mousse).

Meringues start out by whipping up liquid egg whites into a foam. By whisking an egg white you’re incorporating air bubbles into the liquid egg whites. Sugar is either added at the start, or later while whipping. Meringues might undergo a heat treatment (or not).

whipping up Italian meringue
Light and fluffy egg white foam

It’s a foam

Scientifically speaking, meringues are foams. Foams consist of two separate immiscible phases: one liquid or solid, the other one being a gas. In a foam, the gas is dispersed throughout the liquid (or solid) phase.

The tricky thing about foams is that most aren’t stable over time. The individual gas bubbles that are dispersed throughout the solid or liquid want to merge together again, energetically that’s more favorable. As a result, a lot of foams collapse over, caused by the gas leaving the other phase. When making meringues, you’ll find that a common theme is how to stabilize that foam for long enough! Sugar plays a key role here, but so does a heat treatment.

Why egg whites foam so well

The starting point for most meringues is an egg white. Understanding why that egg white can get so foamy is crucial to understanding the science of meringues. Once you start whipping that egg white it starts to become foamy. This is quite a unique property. If you’d try the same with pure water, you wouldn’t even get close to getting the same airiness! But why?

To answer that question, we have to look at the composition of the egg whites themselves. Aside from water, most of an egg-white is made of proteins, about 10%. Egg whites barely contain any fat or carbohydrates and it’s the proteins that give the egg white its special properties.

Proteins are a very common type of molecule in food (as you can learn in our Food Chemistry Basics Course). They are made up of long chains of building blocks called amino acids. These long chains curl up and fold in very specific ways which make the proteins do their job (e.g. as an enzyme).

When proteins are unfolded you expose all the amino acids that make up the protein. Different amino acids have different properties, for foam stabilization in meringues their hydrophobic vs. hydrophilic properties are important. Parts that are hydrophobic do not like to sit in water, whereas the hydrophilic amino acids prefer to sit in water. Proteins can have sections of both.

ovalbumin structure from Wikipedia
Ovalbumin protein from Wikipedia

Denaturing proteins

Egg white contains a mixture of proteins, the most prevalent one being ovalbumin. What’s special about this protein is that it can be denatured (unfolded) quite easily, simply by using some mechanical force (here’s where a whisk comes into play). This in and by itself is quite special. Not a lot of proteins denature as well as this protein does when agitated mechanically. A lot only denature when exposed to heat, others barely denature at all!

By whisking and thus unfolding the protein, you expose the long chain of amino acids that makes up a protein. Parts of this unfolded protein chain like to sit in water, whereas other parts do not (hydrophilic vs. hydrophobic sections). The protein will arrange itself in such a way that most sections can sit in their preferred space.

Aligning on the interface

In the case of an egg-white foam this means that the hydrophilic parts will align themselves along the water present in the egg. The hydrophobic parts on the other hand will arrange themselves alongside air bubbles, since they don’t like to sit in water. As a result, these proteins lie on the interface between water and air. As such, they stabilize the air bubbles within the water, it will be harder for the air bubbles to ‘meet’ one another again. The structure and composition of egg white proteins are such that they are really good at this job, far better than many others!

That said, egg white proteins aren’t strong enough to hold on to the air forever. Over time, the air bubbles will coalesce and the egg white foam will collapse again. This is where additional stabilization of the meringue comes into play.

We’ve discussed the science of foams and why and how they collapse over time in far greater detail in a separate post.

Egg-less meringues

Egg whites have traditionally been the go-to ingredient for meringues because of those special proteins. There aren’t a lot of ingredients that can compete. So far, the ingredient that gets closest is aquafaba. Aquafaba is the leftover liquid from cooking chickpeas. It also has surprisingly good foaming properties, though it does still fall a little short compared to egg whites. That said, you can make good meringues with it. The science behind those meringues is pretty similar to those made with egg whites, as we’ve explored in more detail here.

Apart from this naturally occurring product, ingredient manufacturers have been working on finding other alternatives. Knowing how egg whites work, they’ve developed a soy based protein that can also be whipped up (e.g. Versawhip 600K). Here the soy protein has been modified in such a way that it can also be whipped up (whereas ‘regular’ soy protein wouldn’t!).

How sugar stabilizes an egg white foam

Even though egg whites are great at foaming up, they need additional help to create a foam that’s stable over time. This is where sugar comes in. Sugar will dissolve in the water (liquid) from the egg white. As a result, it increases the viscosity of the watery phase. If you’ve made sugar syrups before, you will have noticed that higher concentrations of sugar make thicker, more viscous syrups.

By increasing the viscosity of the water phase, the sugar makes it harder for the air bubbles to merge together and escape (read more about those mechanisms here). As a result, an egg white foam that contains a good amount of sugar (a small pinch won’t help you here) will take a lot longer to collapse than one that doesn’t contain any sugar.

Powdered sugar vs granulated sugar

Depending on the type of meringue you’re making, you might be adding quite a lot of sugar to your meringue. Ideally, most (if not all) of that sugar dissolves in the water of the egg white. This way you won’t have any grittiness from any remaining sugar particles. In some recipes, however, the concentration of sugar is very close to the maximum amount of sugar that can dissolve in water at room temperature. This can make it challenging to dissolve all the sugar.

This is where choosing an appropriate sugar particle size comes in. Smaller particles of sugar dissolve in water more easily. Larger particles can take a lot longer to properly dissolve. It is why recipes for very smooth, delicate meringues will often call for using icing sugar. The icing sugar consists of very small sugar crystals that dissolve quite rapidly!

You will mostly see this for meringues that don’t heat the sugar and/or the egg whites before or during whipping (e.g. French meringues, see below). If your meringue involves a step in which you heat the sugar in a liquid this is less important. The heating step increases the speed at which sugar dissolves, making it easier to dissolve larger particles!

Since you want to dissolve all this sugar (else it will become gritty) recipes tend to call for using powdered (icing) sugar. The only difference between powdered and granulated sugar is the particle size. That of powdered sugar is a lot smaller and as a result, it dissolves a lot more easily.

When to add the sugar

When making a meringue you could add all the sugar with the egg white from the get-go and whisk them together. However, you could also whip the egg whites first and add your sugar later. The order of addition can impact the result of your meringue and will depend on the type of meringue you’re making. There isn’t a right or wrong, both will make meringue, just a slightly different texture. We won’t dig into the details here, but you can find more information in articles digging deeper into specific types of meringues (e.g. Swiss or Italian meringues).

lemon with italian meringue pies
Lemon tart topped with Italian meringue

The disadvantage of using sugar syrups

Since the sugar needs to increase the viscosity of the water naturally present in the egg white, it’s best to use dry sugar instead of a natural sugar syrup such as maple, rice or agave syrup. Sugar syrups already contain a lot of water themselves and won’t be able to increase the viscosity of the egg white enough.

If you’re using egg white powder instead of liquid egg whites you could give these sugar syrups a shot! Since you will need to add water anyway, adding (part of) the sugar as a liquid can make a stable meringue. You will need to tweak ratios to get that optimal ratio of water : proteins : sugar.

Bonus: Sweetness & Browning

Sugar is mostly there to help stabilize that meringue, however, it does more. First of all, it sweetens the meringue and thus provides some flavor. Second, it makes it easier for the meringue to turn brown, e.g. upon blow torching the meringue. The sugar can caramelize because of the heat, but, more importantly, the sugar + proteins in the egg white can react in the Maillard reaction, also causing the meringue to turn brown!

bruleed italian meringue on lemon meringue pie
Use a blowtorch to brown a meringue topping, such as this Italian meringue.

The role of heat in a meringue

Even adding sugar to a meringue won’t make it stable for that long a time frame. Over time, most raw meringues will still collapse, often in a matter of hours. This is where the third major factoring for stabilization comes in: heat. It can help stabilize a meringue in several ways.

Cook the proteins

Those egg white proteins have been denatured during whipping, causing them to unravel and unfold and align themselves along the water:air interface. However, you can denature them more permanently by heating the proteins. This is what happens as well when you cook/boil an egg. The egg white transforms from transparent into white. Most of this transformation is due to the proteins ‘cooking’. Once cooked, there is no way you’ll get back to your initial egg white anymore, it’s been changed permanently.

By fully cooking your proteins in the meringue, they can be stable for a very long time (although generally, it still is important there’s not too much water, see below since that will keep it somewhat unstable). When making French meringues (see below) you’re using this technique.

Dissolve (more) sugar

At higher temperatures, you can dissolve more sugar in less water. Some meringues use this aspect by making a hot, very concentrated and thick sugar syrup. By adding this hot syrup you can both add a lot of dissolved sugar and use the heat of the syrup to ‘cook’ some more of those proteins.

Evaporate moisture

As long as you have a foam of air bubbles in a liquid (e.g. water) it is almost inherently unstable. However, if you get rid of enough of liquid (aka water) in your meringue you can create a solid foam. In a solid foam the gas bubbles are dispersed into a solid phase (in this case a matrix of mostly sugar and proteins and just a little water). Bubbles are pretty much trapped here.

You achieve this by first making the meringue and then subsequently baking the meringue, to evaporate any excess moisture. The tricky part here is always to do it slowly though. Since a meringue is mostly sugar and proteins, it’s very prone to browning and burning. Also, the water is trapped quite well and will need time to slowly evaporate without breaking the structure. You use this ‘trick’ when making French meringues.

Italian meringue ice cream
Another (not so common way) to stabilize a meringue: make it into an ice cream! Here we’ve folded Italian meringue with some frozen and ground down berries. The ice cream held its shape, airiness and flavor for weeks.

Other ways to (de)stabilize meringue foams

The major aspect of successfully making a good meringue is to manage its stability. You want your meringue to stay light and airy for long enough for your application. In some cases you might only need it to be stable for a few hours, in other cases you’re looking at days. Egg whites, sugar and heat are the core ingredients for managing stability. However, there are a few other factors that can either greatly increase or decrease the stability of a meringue!

How egg yolk destabilizes an egg white foam

Before we dive even deeper into the world of meringues, let’s make clear that you really should only use the egg white and not the yolk for making a meringue. A yolk also contains proteins, but apart from that, it contains fat, which egg whites don’t. This fat can ruin your meringue.

As we discussed, proteins stabilize the egg white foam by unfolding and sitting on the surface between water and air. However, if fat is present, these proteins will not just sit on the water/air interface. Instead, it will probably prefer to sit on the fat/water interface, somewhat acting like an emulsifier. This severely limits the foam stabilization properties and as a result your foam won’t be as stable and will collapse a lot more easily.

Impact of lemon juice & cream of tartar

Many recipes will call for using lemon juice or cream of tartar in your meringues. Both of these help stabilize your foam. In a lot of cases you can do without them but it will just give a slightly less stable or less firm foam.

Both work by lowering the pH-value of your egg white mixture. In other words, it makes the meringue mixture more acidic. These lower pH-values help the proteins to unfold and thus helps stabilizing your egg foam even better.

Marshmallows, started out as an egg white foam

Adding gelatin (and other stabilizers)

You can of course stabilize the meringue even further by adding other ingredients. A common ingredient you’ll find is gelatin. It’s what helps transform meringues into a marshmallow! Even though this is a suitable way to stabilize a foam for a long period of time, you wouldn’t call these foams meringues anymore. You’ve simply made another dish.

The reason an ingredient such as gelatin works is that it literally ‘gels’ the meringue. The gelatin molecules form a complex entangled network of molecules that help to stiffen the water phase. It becomes even harder for individual gas bubbles to travel through the liquid phase, stabilizing the foam for a long period of time!

Adding butter (buttercream meringue)

This stabilization trick is similar to that of gelatin, you’re adding another ingredient to help add stability to your foam. However, instead of adding a gelling agent, here we’re adding an ingredient that turns solid over time. Butter, but also chocolate for instance, can be melted down and mixed through the meringue. They will set and solidify again upon cooling. As a result, you now have gas bubbles trapped in a solid phase which makes it even more stable over time.

That said, most people won’t call these dishes meringues anymore, instead, you might have created a Swiss meringue buttercream or maybe even a chocolate mousse!

chocolate cupcakes with swiss chocolate meringue buttercream
Cupcakes topped with Swiss meringue buttercream

Types of meringue – French, Italian, Swiss

There are a lot of different types of meringues. A common way to classify them is by origin (though whether that’s truly their origin, who knows): French, Italian & Swiss meringue. Whereas the names aren’t always used consistently, these three types do distinguish between three key ways to stabilize a meringue.

French = Baked

The French version is quite a stable type of meringue, thanks to the fact that it’s been baked in the oven. As most meringues do, the French version starts out by whipping egg whites and adding sugar to create an even fluffier foam. The foam is then baked in the oven (see recipe at the end of this post). Depending on how long you bake them for they either turn out completely crunchy, or still have a slightly soft center.

Before placing the French meringues in the oven you had a liquid phase (sugar + water) in which you had dispersed a gas phase (the air). By baking them in the oven you evaporate a lot of the moisture from the liquid phase. As a result, it turns solid and crispy. Solid foams are a lot more stable than liquid foams. The gas bubbles are trapped more securely and will have trouble finding one another. As long as you store French meringues away from moisture (which can soften the meringue again) they can be stored for a long time.

Italian = Hot sugar syrup

An Italian meringue starts by making a hot, concentrated sugar syrup. By making the sugar syrup you dissolve any and all sugar crystals. This ensures you get a super smooth meringue.

Once the sugar syrup is ready (which depends on your recipe) you add it to freshly whipped up egg whites. The heat from the sugar now partially cooks the egg whites, helping its stability and increases the viscosity of the water phase thanks to all the dissolved sugar!

Swiss = Au-bain marie

Last but not least, in the so-called Swiss version you gently heat up the egg whites and sugar together while whipping it. Once they’ve reached the temperature you’re aiming for you increase whipping drastically. This meringue definitely isn’t crispy, but it is very light and airy and even stable enough to pass through a piping bag without losing all the air again.

Of course, within these different types, there are again countless possible variations. You can add colors, or flavors, change cooking times and ratios of ingredients. However, all follow the same science that we just discussed, so you should be good to go to let those egg whites shine in a new meringue!

Further reading

Cook’s Illustrated, What’s the Difference Between French, Swiss, and Italian Meringues?, link

Fabio Licciardello, Pierangelo Frisullo, Janine Laverse, Giuseppe Muratore, Matteo Alessandro Del Nobile, Effect of sugar, citric acid and egg white type on the microstructural and mechanical properties of meringues, 2011, Journal of food engineering, link

K. Lomakina, K. Mikova, A Study of the factors affecting the foaming properties of egg white – a review, 2006, Czech J. Food Sci., 24: 110–118., link

Harold McGee, On food and cooking, 2004, p. 108-110

Modernist Pantry, Versawhip 600K, link ; want to try egg less meringues? this is one of the commercially available alternatives

Vassilios Raikos, Lydia Campbell, Stephen Euston,Effects of sucrose and sodium chloride on foaming properties of egg white proteins, 2007, Food Research International, DOI: 10.1016/j.foodres.2006.10.008, link

Nicole Rees, How to make meringues, from Fine Cooking #128, pp. 78-85, link

The Science of Cooking, What does salt do to a meringue mixture?, on Exploratorium, link

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  1. I LOVE your Blog Post on Meringues.

    Are you in Holland? Do you often post Dutch Recipes?

    I ask because I am looking for some Dutch Recipes
    and I am not having much luck finding a good Dutch Appelflappen.
    I have an old Dutch Cookbook, and use it for my Oliebollen, But, the Appelflappen
    is just making me a bit lost. 🙂

    I live in Sweden and all the Appelflappen Recipes I am finding call for self-rising flour,
    we don’t have this in Sweden.

    I have noticed that the difference between the Oliebollen, and the Appelflappen
    is that Oliebollen uses yeast, and it seems that Appelflappen uses baking powder.

    anyway, I look forward to reading more of your blog.

    • Hi!
      Thank you for reading my blogpost :-), I haven’t been writing a lot lately, but trying to write some more the coming time.

      Finding an English recipe for appelflappen might indeed be difficult, in my Dutch cookbooks I could find several :-).

      The easy way to make appelflappen is using store bought puff pastry (generally the frozen type). In the Netherlands you can buy this in squares of approx. 15-20 x 15-20 cm. Cut some apples in pieces and mix with sugar and cinnamon (to taste), place some apple mix in one half of the puff pastry and then fold the upper left corner onto the lower right corner to form a triangle. Fix both sides together with a fix and decorate with some egg to get a nice brown crust. Bake the puff pastry according to the instructions of the pack (generally 15-20 min at 200C. This is a method I generally use.

      In one of my recipe books I found a similar method, using either store bought puff pastry or ‘Hollandse korst’, which is a recipe for a Dutch puff pastry. It’s too complicated to completely explain here, but it consists of making a puff pastry dough from 500g flour + 3/4 tsp salt + 500g cold butter + 275 ml water. Cut the butter in cubes and gently mix with water and flour. Then follows a process of folding the dough, resting and cooling it, folding it again, etc. Just like with puff pastry. Once the dough is made they use half this amount for making 8 appelflappen. For eight appelflappen they mix 2 big apples (cut into pieces) + 35g sugar + 1 tsp cinnamon + 1,5 tbsp corn starch (Maizena in Dutch, which is just a little different from corn starch) + 35g raisins. This they use to fill the squares of dough and also coat with egg. It’s baked in the oven at 200C for 15-20 minutes. It’s pretty similar to what I do, feel free to vary quantities etc. to taste.

      Hope this helps :-).

  2. I’ve learned science at school and baking on-the-job in a kitchen but I wish I could’ve studied the science of baking as well! So now I read a lot about the topic to understand what’s happening in my mixing bowls 🙂 I’m glad I found your blog!

  3. Excellent article for those of us who want to dig deeper into the details of things!

    You say, “There are of course a lot of moments you can add sugar to your egg whites, but there are two extremes: either at the start, before start to whip, or at the end, when you’ve already got your foam.”

    Which method is best if I want to pipe bite-sized meringue drops that have chewy interiors?


    • Hi Linda,

      Thanks for that great feedback, very glad to hear it’s helpful. In my experience, both methods should work for small drops. I have not tried all methods myself, but I would suggest you start by adding everything in at the start (simply because it’s way easier!). If that texture isn’t entirely right en you’d like it somewhat smoother, I would suggest trying the other extreme and then based on that, choose which one works best for you!

      Good luck and I’d love to hear what you choose to do!

  4. Hi there, just read through your article trying to troubleshoot something. My daughter and I make macarons using the Italian meringue method. Lately, in our meringues we notice these little strands that feel like plastic. We have noticed them in our meringues using two different types of sugar (Domino and Dixie Crystals), both of which are supposed to be pure enough for merengues. Any ideas what this could be from? We are usually able to see most of them during piping the macarons but of course some sneak through which always is a nice surprise. Thank you for any insights!

    • Hi Katie,

      Thanks for teaching me that you can make macarons using the Italian meringue method! I’ve always made them using the French method, so I’ll need to add the Italian version to my experimentation list!

      But to come back to your challenge, assuming that you don’t actually have plastic in your batter (you’re not heating plastic causing it to melt?), I would expect that these strands are made out of sugar. When you make a hot sugar solution and pour it into a mixer while it’s whipping (which I’m assuming you’re doing) you might swirl some of the hot sugar solution to the side of the bowl where it cools down and forms a firm strand. Even mixing this into the batter again won’t get rid of these, only heat will help them dissolve again. Normally though, these loose strands would be caught onto your bowl and they wouldn’t transfer in your batter that easily. Maybe some of them break apart and do end up there? If this is happening, you should only have a few of them.
      You could solve this by whisking more slowly while adding the sugar syrup, preventing it from spinning to the sides.
      If you want to test whether they are made of sugar, take one of the strands next time you encounter them and place them in some warm water. Heat the water up, if it dissolves quite easily, it’s probably sugar!

      If this can’t be the problem, please tell me more about how you’re making them to see if there’s something else that could be causing this plastic-like strands!

      • Thank you very much! I also reached out to a pastry chef friend of mine and she said basically the same thing: to avoid hitting the whisk when pouring the syrup into the egg whites (this is difficult for me – i will slow the whisk down even more) but also to wait maybe a minute or so after letting the syrup get to temperature before adding it. There should be no plastic coming into contact with anything, so it must be something with the sugar. And we do see them mostly clinging to the wire whisk, and yes there are only a few. If any sneak through my daughter usually catches them when she’s piping the shells.

        We have much more success using Italian meringue with our macarons. In our climate, the french ones are unstable. My oven is old and non-convection, so I can only cook one pan at a time. Even the relatively short time the french method batter was sitting out caused it to do some funky things. We don’t lose any when we do the Italian meringue method.

        Thank you so much for your help and suggestions!

      • Okay more of the same weird meringue adventures. The “plastic” strands are not sugar. They did not dissolve in hot water. We are thinking it’s the eggs cooking?! How would you avoid this? We have the eggs at room temp and we let the syrup sit for about a minute before adding it to the partially whipped whites. Is it possible we’re adding the syrup too quickly? Thanks.

        • Hi Katie,

          The mystery continues! I’m not too sure what’s going on here, it would almost have to be the eggs if it’s not the sugar, there’s not a lot more in there! The proteins in eggs do denature, which is a permanent, irreversible change (unlike the sugar, which should dissolve back in hot water). Are they very sticky? Do they stick to the bowl? Normally, you’d want to pour the sugar quite soon after heating it since cooling down can cause it to solidify and harden. I couldn’t imagine though that leaving it to sit for a little while should make much of a difference, it tends to take me a little while to get everything ready to pour. If anything, I’d think you’d have to pour sooner, not later, but again, can’t see how that one minute should make the difference.

          Could you whip the eggs a little more? Once they’re a foam, they hold together in a different way than when they’re liquid? It’s really just a guess because you’re starting to run out of other options here!

  5. I love the baking fundamental posts! So helpful for a newbie like me. I will be looking out for that cake and buttercream recipe!

  6. Hi and thanks for the post! I would love to know more about this: “By changing the ratio of sugar to egg white as well as by changing how and when you add the sugar, you can change the structure of your meringue.”
    It seems that there are many factors – the ratio of sugar to egg whites, when that sugar is added and how firm the meringue peaks are (soft vs. firm vs. stiff).
    Ultimately, I’m trying to understand how the consistency of the meringue affects the foam cake (Angel Food, Chiffon, etc.) texture?

  7. As soon as I saw this I knew I had to make these- so my son and I made them last night. They’re fantastic!! Delicious and addictive.

  8. I’m trying to make crispy meringue inside and outside. However, my meringue always attracts moisture and becomes sticky and chewy (not what I want at all). I’m using 2 eggs with 80g sugar added gradually and baked at 140 degrees celcius for 1 hour. Kindly advise what I can do to keep the meringue crispy for Long? Thank you!

    • Hi Becky,

      Over time a meringue will always become softer, especially if you live in a humid climate. If your meringue is crunchy when it comes out of the oven, cool it down, and once it’s at room temperature, store in an air-tight container. This will prevent extra moisture from coming in and softening the meringues. If you use meringues on pies etc. they’ll become soft over time as well, it’s the migration of moisture and that’s hard to stop! Your best bet here is to add them as late as possible.

      If your meringue doesn’t get crispy at all, try baking it for longer at a lower temperature (so it doesn’t brown/burn) to dry it out even more. The drier the crispier!

      Hope that helps!

  9. A step in the right direction is to have your stainless steel bowl & beater COLD! When trying to whip up anything, be it egg whites, whipping cream, heavy cream, etc, it helps if you have your utensils cold.

  10. This is the most Informative information I’ve ever seen on eggs and sugar. This better comprehension will without doubt aid in my future experiences. Thank you ever so much.

  11. Know I am late, very late to this post, but hope I can get an answer.
    I am trying to recreate the filling a bakery in my hometown, in the US, uses in their Cream Horns. (I am actually in England, and told on the QT that it’s egg whites and sugar. That’s all the info I have.) Here’s what I can tell you about the filling. It requires no refrigeration, the Horns are kept on display in the shop and taken from the shelf or tray. When biting into the ‘cream’, it has a slight crust, it’s very glossy looking, and while light, it has a little more resistance than normal meringue.

    From what I have read, a egg whites with icing sugar, aka powdered sugar, along with a sugar syrup should perhaps be the answer. I would probably start by adding the icing sugar to the egg whites before beating because I am after a dense meringue.
    Does any of this sound like it would work, or am I completely on the wrong track?
    (I really stink at this ‘science’ stuff! I have a liberal brain, not scientific! I bake and cook by instinct! 😉 )

    • Hi Marri,

      A great treasure hunt :-). What you describe reminds me a bit of a Swiss meringue. A Swiss meringue is still a meringue with egg whites and sugar but is soft (though you can make the outside crispy by drying it to the air or even browning it with a blow torch). The main difference with the oven-baked meringue is that you heat and stabilize the egg whites by pouring in a very hot sugar syrup.
      It is not permanently shelf-stable, but you can keep it outside of the fridge for one or two days if you cook the sugar syrup hot enough to pasteurize the egg whites (or use pasteurized egg whites to be on the safe side to start with if this is a must).
      We’ve got a recipe here.

      Does this sound about right? If not, let me know and we’ll continue looking :-)!

  12. Hi,
    I have been making swiss meringue buttercream for my wife who’s cake business is exploding. I am an engineer so following proceedures in baking is easy but for some reason I cannot figure out how to make larger batches of SMB (20 egg white size) without it getting very yellow or getting the hard clear pieces in it. I make 10 egg white size batches all day long but once I start increasing the size of the batch it ruins. This website is amazing and you have done a great job explaining the science behind the baking. thank you so much

    • Hi Bakerhelper,

      Thank you for your question and glad to hear you find the articles on our website helpful! Also, congrats to your wife whose cake business is doing so well, that’s really exciting :-).

      With regards to your Swiss meringue buttercream challenge. When scaling up recipes like this the most challenging part tends to be a change in heat distribution. Larger batches can have bigger temperature fluctuations and need longer to cool/heat. With a delicate product like Swiss meringue, this might be a challenge for you too. A few thoughts, hope these help!

      • You’re heating up the egg whites with sugar at the start. With a larger batch this will take longer and increase the risk for part of it overheating. Also, a larger batch will keep its temperature for longer (assuming you’re using similar bowls etc.) since there’s more mass. Using a pan (that contains the hot water for the double boiler, if you’re using it) with a larger diameter might help here to get a more even heating of the bowl. Also, you could experiment around a little, since heating will take longer you might be able to use a slightly lower temperature (really just a few degrees) to get the same effect with regards to denaturation of your proteins. Of course, do make sure you meet the requirements for pasteurizing your eggs if you’re using fresh egg whites. If the proteins denature more than for the small-batch this might change just how well they’re able to hold onto air.
      • Do you know what the hard clear pieces are? Have you tried dissolving them in (hot) water? If they dissolve, I would expect them to be sugar. If that’s the case your sugar might not have fully dissolved in the first step, so keep an eye on whether that’s happening properly.
      • If those hard pieces are sugar they could also be formed when adding the butter. If sugar gets shocked cold it can set quickly and once it has formed a glass (which is what we’d call this state of sugar, more on that here) there’s not really any turning back for a Swiss meringue.
      • Do you check the temperature of your egg white mix during the different stages of making the buttercream? It might be a bit more crucial to get them right for the larger batch simply since the system isn’t as flexible. Small quantities cool down quicker and heat up faster which can sometimes help ‘fix’ issues.
      • You mentioned it turning yellow. I’m assuming that happens after the butter has been added. The egg white + sugar mix should definitely not be yellow. Its whiteness is a sign that a lot of air has been incorporated (the air bubbles reflect light differently). If the egg white + sugar turns yellow all I could think of would be caramelization of the sugar, but that shouldn’t happen at the temperatures you’re working with. Therefore I’d expect the yellow to come from the butter. I’m thinking it might not emulsify (mix in) properly here. Maybe some of the fat splits out or melts too much making it unstable and changing the color. This is also where temperature control is important, as is adding the butter in small enough portions. Again, because your batch size is larger the meringue might not be able to cool down as easily anymore, and you might need to cool for longer before adding the butter (to prevent it from melting too much). Worth experimenting.

      All in all, what I’d suggest you do is a few tests to see what might be helping here:

      • Test whether those hard pieces are indeed sugar.
      • Measure the temperatures when making the small batch at crucial stages (e.g. when adding the butter) and noting down the time it takes for the individual steps. Then do the same for the larger batch to see whether you have any major deviations.
      • Be (more) careful when adding the butter in the large batch to see whether that helps prevent the yellow color.

      Also, just in case you haven’t read it yet. We also have an article dedicated to Swiss meringue buttercream that might help you!

      Good luck!

      • Thank you so much for such a well written response to my question! I really do appreciate your logical thought process and it reminds me of when I had labs back in school. I will be taking temperatures at intervals during the small batch process and if I get any of the hard pieces I will test to see what they are. (I don’t know why I didn’t at least keep a few to examine, might have been frustration at 11pm at night!)
        The yellowing is after the butter is added so temperature in the center of the bowl could be the problem again.
        when I was heating up the last 20egg batch I was thinking to myself that this is too big for the double boiler setup I have for the 10 egg batch. I will have to play around with larger pots and bowls like you suggested.
        Thank you again!

    • Hi Celine,

      I haven’t tried either of them. Their composition is slightly different so I would expect you might have to adjust the ratios and the result will of course look different (different color). If you do give it a try, let us know how it went!

  13. Hi
    I have used a meringue recipe many times before that requires 4 large egg whites and 220grams of caster sugar. The meringues are always excellent. The BBC has a recipe for four large egg whites and only 115 grams of caster sugar. Why is there such a disparity between the two recipes, and what is the difference between the finished meringues?

    • Hi David,

      We actually did a test with this a while back (didn’t get to writing it up yet!). We found what you found, that most recipes fall within a ratio 1:1 sugar:egg white or 2:1. They both make a meringue, but their structures are quite different.

      We found that the meringue with the high sugar content (that you be your original recipe) makes a denser meringue, with a lot of small air bubbles. Our meringue in this style was very white in color. The eating experience is quite different, though hard to describe.

      The meringue with the low sugar content on the other hand has larger air bubbles and is less white in color. It is a little airier, crunchier and since the air pockets are bigger, breaks down differently in your mouth.

      Both make a meringue, just a different style. Which one you choose depends on your personal preferences and what you’ll be using it for.

      Does that seem to agree with what you found?

  14. Many thanks for this. Yes, I got this result also. My fellow diners prefer the denser meringue, when I use fruit and cream, as in Eton Mess.

  15. Thanks for this very educating article. I have quick question. Can I substitute regular sugar with stevia or monkfruit sugar? will that make good french meringue?

    • Hi Victoria,

      Stevia and monkfruit sugar both work quite differently than regular sugar would here. I’m sure you could make something with it, but the texture will be different, it just doesn’t have the same properties regular sugar does. Also, there are a lot of different types of brands out there and these can vary a lot. Some may say they are a 1:1 replacement for sugar. If you’re using one of those, I would just give it a try with a small portion of meringue (just use one egg white) and see what happens. You might need to add a little more (or less) to get a decent meringue. All to say, you might be able to do it, but it won’t be an exact 1:1 replacement.

      Good luck!

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