Want to learn how to troubleshoot three common candy making challenges?
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Want to learn how to troubleshoot three common candy making challenges?
And learn WHY they work? Sign up for our free mini-series!
Press into a marshmallow. And let it go. What happens?
It should have bounced right back up, thanks to some great teamwork of a mere three ingredients: sugars, gelatin, and possibly egg whites.
Egg whites make marshmallows light and airy. Gelatin is the mastermind behind that bounce. And don’t forget the sugar, without it, a marshmallow wouldn’t be.
Marshmallows are a very light style of candy. They float on top of hot chocolate milk and even a handful doesn’t seem to weigh anything. That’s because marshmallows are a foam. They contain a lot of tiny air bubbles which are surrounded and stabilized by sugar and proteins from egg whites and gelatin. Since air doesn’t weigh much, adding it into a product decreases its density. That is, the same volume of that product will weigh less.
Marshmallows aren’t the only food foams out there. Ice cream, foam on top of a beer, chocolate mousse, these are all foams as well. What sets marshmallows apart though is their bounce. You can compress them. But, they’ll bounce back upon release. Try doing that to ice cream or chocolate mousse, and you’ll simply see a fingerprint left behind.
It’s the delicate interplay of a marshmallow’s three core ingredients that makes this possible: sugars + gelatin + egg whites. Let’s have a look at each and how they impact the texture of marshmallows.
Look at the label of a pack of marshmallows, or a marshmallow recipe – we have one at the bottom of this post. Most likely, the main ingredient is sugar. Of course, sugar makes marshmallows sweet. But that’s not all, a marshmallow wouldn’t be able to hold its shape without the sugar!
As a thought experiment, remove the sugar from the marshmallow recipe below. You’ll be left with just 2 egg whites and a few grams of gelatin. You can’t make anything that resembles a marshmallow from just those ingredients. What’s more, removing the sugar will make it virtually impossible to make a nice brown marshmallow during roasting.
Most marshmallows don’t contain just one type of sugar. Often, they’ll contain regular sugar as well as corn syrup – also referred to as glucose syrup. They each have a slightly different role:
For some recipes, you may be able to replace the corn syrup in marshmallows with honey. Honey is a mixture of different types of sugar, but it does have a different composition than corn syrup. It can help prevent the crystallization of sugar, but may also make a marshmallow stickier. Lastly, keep in mind that honey has quite a strong flavor. For some, this is an advantage, for others, not so much.
Regular sugar is grainy and made up of large crystals. Marshmallows on the other hand are very smooth and don’t contain any rougher particles. This is why sugar has to be dissolved in water first. By dissolving the sugar, the sugar crystals break down and the sugar syrup is fully liquid, not grainy.
Once the sugar is dissolved, you’ll have to cook the sugar syrup. By boiling a sugar syrup, you evaporate water. The hotter the sugar syrup, the more water you’ve evaporated.
By concentrating the sugar syrup it becomes more viscous. This helps ensure that your final marshmallow will be dense, stable, and firm.
The temperature of a hot boiling sugar syrup is a measure of its concentration. The higher the boiling point, the more concentrated it is. Recipes for marshmallows generally give an exact temperature to which a sugar syrup should be cooked. This ensures that the concentration of sugar is high enough.
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Once that sugar syrup is hot enough, you’ll have to pour it in with the egg whites and gelatin. It needs to be poured in while it’s still hot. This way, it will:
Even though sugar plays a crucial role in marshmallows, it alone cannot make a marshmallow because it lacks a crucial function: foaming capability. You can’t incorporate air bubbles within a sugar syrup, especially not ones that will remain there over time.
Egg white proteins on the other hand are exceptionally good at foaming. The proteins in the egg white can easily stabilize the air bubbles that you can incorporate by whisking the egg white. Meringues use this powerful functionality as well, and are actually quite closely related to marshmallows.
These proteins can do this so well because when they are whisking, they unfold. Each protein is essentially a long chain of different building blocks. Some of these want to sit in the water of an egg white, the hydrophilic regions. Others prefer to get into contact with the air bubbles, the hydrophobic regions. This way, they surround air bubbles in a way that stabilizes them within the foam.
Note, this only works with egg whites, not egg yolks. The yolk contains fats that can actually destabilize the egg white foam.
An egg white foam will collapse over time if it is not stabilized additionally. In a marshmallow, this stabilization is done in two ways. First of all, the hot sugar syrup helps to stabilize the foam. The high temperatures help to ‘cook’ and set the proteins in the egg white. Much like how an egg becomes solid when you boil or fry it.
Secondly, gelatin adds an additional and crucial layer of stability.
Gelatin is also made up of proteins. These proteins work a little differently than egg white proteins. When gelatin cools down it can form a gel. It holds on to the surrounding water, firming up the marshmallow.
Gelatin can form very stable, firm, and most importantly bouncy gels. Jello puddings, panna cotta, they all get their wobble or bounce from the gelatin. As a matter of fact, it’s very hard to replicate this exact texture with any other ingredient. It’s why most gelatin-free versions of candy do have a different texture than that of their gelatin-containing counterpart.
Did you know that the ‘original’ marshmallow did not contain gelatin? Instead, it was made with marshmallow root, hence the name.
Over time the manufacturing process has also become more efficient, nowadays, marshmallows can be made continuously using a piece of equpiment called an extruder.
Even though egg whites do help to make a very light, fluffy marshmallow, you can technically leave them out. The gelatin by itself is strong enough to form a foam and hold on to that foam for long periods of time. A marshmallow made without egg whites does tend to be a little firmer in texture, though also even more bouncy.
A basic marshmallow recipe. It really really helps to use a stand mixer when making marshmallow. If you don't have one, ask someone for help to help you pour hot sugar syrup while whisking vigorously.
*Corn syrup-free marshmallow option: replace the corn syrup with honey. The marshmallows will taste like honey but will still form a good light texture.
**Egg-free marshmallow options: You can make marshmallows without any eggs. Follow the same instructions with the following tweaks:
Undusted marshmallows tend to stick to just about everything. So be prepared for a seemingly daunting cleanup. But, don’t worry! Sugar, gelatin, and egg whites all dissolve decently well in water. Your bowl, tray, or any other surface that seems too sticky, just let it soak in water for a while and clean-up will be a breeze.