Whipped cream frosting is one of several different kinds of frosting known specifically for its airy and smooth texture. However, these characteristics that make it fluffy and creamy can also cause some of its downfalls. Keep reading to see how and why whipped cream frosting works and how we elevate it to make up for its downsides.
Background
A good frosting should be smooth and thick to hold the various shapes and swirls when piped, but also soft enough to spread on a cake and not too runny to drip down the sides. Frosting comes in all colors, flavors, and textures, but the basic idea is a sweet and creamy topping to a cake or other dessert. Whipped cream frosting is particularly good on top of pies, cakes, waffles, pancakes, lattes, sundaes and other foods or beverages, and it's incredibly easy to make! All it requires is using an electric mixture to beat the cream from a liquid to a solid-like foam. But how does this happen?
While making my own whipped cream frosting, I often noticed how fluffy and light the cream was, but also how easily it would lose its shape and sort of melt. I wanted to know how I could keep such an airy cream while making it more stable, so that it would be able to hold its shape hours later. After I introduce a basic procedure for making whipped cream frosting, let's see how I could have made it more stiff for those nice peaks and swirls on my cupcakes.
Procedure
Making the most basic type of whipped cream generally just uses two ingredients: whipping cream and sugar of some kind. However, many other flavors and variations can be added as well. I decided to make a chocolate ganache whipped cream frosting, which is whipped cream and chocolate chips. For my specific recipe with servings and measurements click here.
To make regular whipped cream, chill the bowl and cream in the freezer for 10 minutes. Beat the whipping cream until it holds soft peaks or use an electric mixer. It’s important not to let the consistency turn buttery! Once soft peaks start to form, add sugar and any other flavorings and beat until soft peaks form.
For chocolate ganache frosting, I used a 1:1 ratio of heavy whipping cream to chocolate (semi-sweet baking bars work best, but chocolate chips can also be used). I heated the heavy whipping cream on the stove top with a low to medium heat until it simmered along the edges but didn't boil, then poured the hot cream over the chocolate. I let the cream-chocolate mixture sit for a few minutes before stirring to incorporate the chocolate into the cream. I cooled the ganache to room temperature before beating it with an electric mixer on medium speed.
The frosting was fluffy with a rich chocolate taste. I scooped it into a piping bag and used it to decorate some vanilla cupcakes. However, the frosting didn't seem to be stiff enough to maintain a sturdy swirl, and instead became more flat and droopy. I wondered how I could fix this problem with science!
Science!
First, what is cream even made of? Cream comes from skimming off the top of fresh milk, which is where most of the milk fat is. Milk is a emulsified colloid, a substance where small particles are suspended in another substance but not dissolved, of liquid butterfat globules dispersed within a water-based solution. If milk is left undisturbed, the fat globules will eventually float to the top and gather together, where they can be skimmed away for the cream and leave "skim milk" on the bottom.
Thus, whipping cream is an emulsion - a suspension of tiny liquid drops within another liquid that's not a solution - that usually has around 30% or more milk fat which is contained in small droplets. Heavy cream is pretty much the same as whipping cream, it just has a bit more fat content. The fat in milk is a mixture of lipids, but the most prevalent one is triglyceride, made by combining three fatty acids and glycerol.
Whipped cream is a air-in-water foam—a suspension of gas bubbles in another substance. Unlike egg-based foams stabilized by proteins, whipped cream is stabilized by its own fat. The secret ingredient to turning this liquid heavy cream into a fluffy frosting is air! When whisking the cream, you are adding air and creating a bunch of tiny bubbles. In the beginning, these bubbles easily pop because the surface tension of the cream isn't strong enough to hold them.
However, after time, the fat globules in the cream begin to destabilize as the protective phospholipid membranes are broken by the whisking. This exposes portions of the hydrophobic (water-fearing) triglycerides in the fat, causing them to partially combine into chains. Some of the exposed areas of fat combine and spread around the air bubbles to avoid water. These fat-stabilized air bubbles will link to each other and the whipped cream starts to become more stiff and solid. Other molecules, the water, lactose, and proteins, are trapped in the spaces around these air bubbles. Since the fluffy whipped cream is held up by these exposed triglycerides and the delicate network they have surrounding air bubbles, stiff whipped cream only occurs if there's a lot of them there, so relatively high fat content is necessary.
However, the problem with whipped cream is that it can become droopy and lose its shape, especially under warm or high temperatures. This is why recipes often say to chill the equipment and cream before whipping. As whipped cream is held together by a fat network, it's unstable in high temperatures since fat easily melts (low melting points). Keeping everything cold allows the cream to maintain its solid state and be more stiff. It's also a good idea to stabilize the whipped cream. Stabilized whipped cream can be piped onto cakes and it won’t lose its shape or melt. There are a variety of different methods that work, such as using gelatin, marshmallows, instant pudding mix, cornstarch, or cream of tartar.
Another important note I mentioned in the earlier procedure is not to overwhip the heavy cream. Continuing to whisk past the initial fluffy stage of soft peaks will cause the fat to churn and create butter! This will destroy the phospholipid membranes, exposing larger portions of fat. These newly exposed regions clump with the other exposed fats, causing them to crush the air bubbles. The air is no longer stabilized by the network of fat molecules, causing it to escape. The foam, in turn, deflates, leaving a greasy mess that is essentially butter. Essentially, instead of clumping around air bubbles, the fat molecules smash together and clump into a giant mass, while the water separates and leaves behind solid butterfat.
Conclusion
From the science behind whipped cream, I learned so many different ways to keep my frosting solid and long-lasting, whether it's using cream with higher fat content, making sure not to overwhip, or using stabilizers like gelatin! This could mean future experiments to see which stabilizer works the best to further my investigations into the perfect whipped cream frosting, or even trying to make my own butter. I'm excited to try different variations of whipped cream and see how they turn out, and I hope this post taught you some helpful science to start experimenting with whipped cream on your own!
Link to my chocolate ganache frosting recipe.
Link to my post on the history & culture of frosting and cake decorating.
Want to Learn More? (always cite your sources, kids)
Comments