I saw a picture of whipped coffee on Instagram last Friday, and I immediately put down my phone, went to my kitchen, and tried it out for myself. Now that is the epitome of inspiration!
But really, I was SO intrigued! When I first saw the picture, I thought that maybe it was made from whipped cream, but the person who posted the inspiring picture was a vegan. So then, I thought surely it must be coconut milk. But she had a bottle of almond milk in the background of the picture, and it would’ve made sense to picture the coconut milk too, if that was an important part of the recipe. Turns out, that wasn’t it, either!
The foam is made up of just instant coffee, sugar, and hot water. Then, it’s beaten into oblivious and served over iced milk. Amazing.
The food scientist in me had to figure out the chemistry of it, but there doesn’t seem to be much research about it yet. So, a lot of my understanding is based off inference, and in case you also were curious about how it works, I thought I’d share!
The Chemistry of Whipped Coffee
Basically, the whipped coffee is a foam. By scientific definition, foam is the dispersion of tiny air bubbles inside a liquid. However, air doesn’t like to just stay inside of water, so in order for a foam to form and stay foamy there needs to be some sort of stabilizer.
Often, this stabilizer consists of a protein or a fat that coats the air bubbles and links them together to form a matrix (see picture below) that is surrounded by liquid. With whipped cream, fat molecules surround the air bubbles, and they stick together throughout the small amount of water in the cream and form a nice foam. With whipped egg whites, proteins coat the air bubbles. Coffee contains natural oils, and when instant coffee (very, very concentrated coffee) is dissolved in a small amount of hot water (make a very very concentrated coffee solution), there is enough oil to coat the air bubbles, stabilizing them so that they can stick together and make a foam. The coffee solids and added sugar stick to the water molecules, preventing them from disrupting the delicate oil foam.
At least, that’s what seems to be going on. When I searched PubMed, I couldn’t find any articles on whipped coffee, but I did find this one about espresso crema. Espresso is very similar to the highly concentrated instant coffee/water mixture used in whipped coffee. But instead of being whipped, the high-pressure process of making espresso forces air into the mixture, allowing for a foam to form naturally. In a hot shot of espresso, this foam can be stable for up to 40 minutes! Whipped coffee is, in my understanding, the cold & sweet version of espresso crema.
Anybody else geek out about food science?
- 2 tablespoons instant coffee
- 2 tablespoons white sugar
- 2 tablespoons boiling water
Mix all ingredients together, and immediately begin whipping with an electric whisk, electric mixer, or vigorously by hand (I do not recommend this option) for 2-3 minutes, until stiff peaks form.
Serve over a glass of ice cold milk or cream, or eat with a spoon!