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Have you ever been left with egg whites after making a recipe that calls for egg yolks only? And not feeling like making crispy meringues from the oven, again? Good thing there are other options such as these soft and shiny Italian meringues, or even a soft Swiss meringue!
A disadvantage of these Italian meringues specifically is that, as opposed to those crispy meringues, they can deflate over time. A collapsed meringues really isn’t that appealing anymore is it? A meringue is all about creating that light and airy silky smooth texture.
Fortunately, Italian meringue is actually quite easy to revive and knowing some Italian meringue science will help you understand why!
What is Italian meringue?
As we mentioned in our intro, Italian meringue is just one of many egg white foams out there. To name just a few more:
- “French” meringue, these are crispy and baked in the oven
- “Swiss” meringue, smooth and sweet, pretty similar to the Italian one
- Isle flottante, these are very soft gentle puffs of air almost, used for dessert
- Marshmallow, whipped egg white stabilized with hot sugar syrup and gelatin
All these egg white foams are made out of two main ingredients: egg whites and sugar. Egg whites are crucial since they contain large amounts of protein with some water. By whipping up these egg whites, you incorporate air within the liquid. The proteins then organize themselves around these air bubbles, holding on to the air inside!
Sugar is important to stabilize this egg white airy foam. The sugar will dissolve in the water of the egg white, making the water more viscous. This means it can’t move as easily, so it wo’nt let the air escape as readily anymore. Without any way of stabilization, the egg white foam will slowly collapse again over time. However, by adding sugar you stabilize the foam and you improve the flavour by adding sweetness.
An additional ingredient for any egg white foam that needs to stay airy for longer periods of time is heat. By heating up the proteins in the egg white they denature and fix the foam even better than uncooked. In some cases, like in the case of crispy French meringues, the heat will also dry out the meringue, making it crispy and crunchy.
The thing that sets Italian meringue apart from all these other egg white foams is the way it’s been heated. Instead of heating the whole meringue, you add a very hot syrup into the egg white (while whisking). The heat of the syrup will ‘cook’ the proteins. However, the heat is not intense or long enough to dry the meringue out. As a result, an Italian meringue is silky smooth and glossy. As such, it is great to use for a topping on a pie, a cheesecake for instance.
Making Italian meringue
Making Italian meringue consists of just three, pretty simple, steps (it’s not that different from marshmallow making!). You can find a complete recipe at the bottom of this post, but we’ll discuss the science of each step first. It will help you make a better meringue and help you troubleshoot your Italian meringue!
Step 1 – Whisking:
You start by whisking egg whites up into a nice foam, adding icing sugar once it starts foaming up. You want to use icing sugar here and not any other sugar because of its very small particle size. Icing sugar is the same chemical component as granulated sugar, but it has just been ground down into smaller particles. This way it dissolves into the egg whites super easily and doesn’t create clumps or grittiness.
Step 2 – Sugar syrup:
Next up is making a sugar syrup. For this you simply dissolve regular (granulated) sugar into water and heat it up. Since you’re dissolving the sugar you can use quite a coarse particle size. It will dissolve anyhow, so that particle will be gone anyhow.
You have to boil this sugar syrup to a very specific temperature of 121C (250F). By boiling a sugar solution you’re essentially evaporating water. The boiling temperature of sugar + water solution is a good measure for the amount of water left in your syrup. By cooking to this specific temperature you’ve boiled of enough water to ensure that the final meringue is not too runny, but not yet so much that it might turn too solid at the end.
Ideally, you’d do step 1 and 2 simultaneously. However, if you have to choose, do step 1 first. You can leave the egg whites waiting for several minutes before adding the sugar syrup from this step.
Step 3 – Mix it
Last but not least, you mix the hot sugar syrup, with the whipped egg whites. The heat of the sugar syrup will cook and help stabilize the Italian meringue. The egg whites get denatured and won’t unroll as easily anymore. At the same time, the sugar syrup also adds some extra moisture, which ensures that even though you’re cooking the meringue, you’re not drying it out. Instead, you’re making it softer.
Hot sugar syrup kills
The sugar syrup doesn’t just stabilize the meringue. It is also a great way to kill any micro organisms that might be present in the egg whites. This way, your egg whites aren’t raw anymore and they’re safe to eat (if you really make sure everything is cook properly, you’ll need to validate this).
Saving a collapsed Italian meringue
What’s special about the Italian meringue is that it’s quite a stable foam, however, it is not as stable as a meringue that has been baked in the oven. So it will actually collapse slowly over time.
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An Italian meringue will probably have some denatured proteins because of the hot sugar syrup. However, the proteins are not permanently set in place. This means though that even though the meringue might collapse over time since the air bubbles slowly leave, you can restore this by whipping it up again!
So the trick to revive the Italian meringue is actually really simple: Put your Italian meringue in a stand mixer and turn on the whip on a high speed. Don’t worry if the meringue collapses at first. Whipping it will initially take out all the air that’s still in there! Just keep on whipping at this point in time. After 5-10 minutes you will see it coming up again. You will have restructured all the proteins around the freshly made air bubbles and it will stay stable for a couple of days again.
Problem solved! No need to throw out this smooth delicacy, just add it to your pie again.