I like to think of baking as a nice escape from my very science oriented education and work. I mean, what could be more far removed from cells, proteins, and microscopes than butter, sugar and eggs?
But the truth is, under all that frosting and sprinkles, baking IS science. I got a stark reminder of that last week while baking up a storm for my birthday cupcakes.
So there I was, starting to make my frosting while another dozen cupcakes were in the oven. All was well; butter creamed, sugar added, next vanilla... Mixer going. Then I noticed that something was not right. My intended super creamy frosting was starting to look a lot more like cottage cheese. So I added more sugar, more milk, it didn't help.
At this point I was tired and my brain was probably turning to mush so I put the whole bowl in the fridge and hoped that all would be well the next morning.
It wasn't. In fact it was starting to look more like crumbled feta than cottage cheese. I briefly considered running to the store for some premade frosting but then I remembered this wonderful thing called the internet.
Thankfully Google came to my rescue, as it often does, and I learned a little bit of science behind baking.
You see, buttercream frosting is an emulsion.
1. A fine dispersion of minute droplets of one liquid in another in which it is not soluble or miscible
In other words, frosting, like mayonnaise is a mixture of two things that usually don't mix together, oil and water. But if you mix fast enough and there are a few more ingredients in the mix that can help stabilise it all (like the proteins in dairy and eggs ;) ), the oil and water will emulsify and stay together. So, what I had essentially done when my frosting curdled is accidentally separated the oil and water. To 're-emulsify', I just had to mix really fast (mixer on highest speed) for a few minutes, which is exactly what I did.
Magic? Nope, just science.