If you haven’t heard of the latest come-and-gone Starbuck’s craze, you must be living under a rock! The Unicorn Frappuccino, AKA the most Instagrammable drink on the market, has swept across the nation. This bane of baristas has already been criticized for being a veritable sugar bomb. Now, when people are buying frappuccinos they aren’t doing it for their health. In general, frappuccinos in are a treat to be enjoyed every now and then. Let’s be honest here, the Unicorn frapp isn’t even the most sugary thing on the Starbuck’s menu board. That aside, let’s talk about what makes the unicorn frapp so cool: dat color doe.
A quick glance at the ingredient list in this magical elixir provides us a glimpse into the beautiful cacophony. The magical ingredients we’re most interested in here are the Sour Blue Powder and the Pink Powder. The blue hue is provided by spirulina, a blue-green algae, and the pink comes from a mix of fruits and vegetables, including apple, cherry, radish, and sweet potato. The real magic happens happens when you mix your frappuccino and watch it turn from purple to pink!
But is it magic? Or, more likely…chemisty? The other secret here is the citric acid in the sour blue powder. As you mix the drink, the citric acid is mixed in causing the whole drink to become more acidic, which is also why the flavor changes from sweet to sour.
But why does this cause the color to change?
The pigments responsible for the color in the pink powder are anthocyanins. Anthocyanins are present in many fruits and vegetables including blueberries, cranberries, red cabbage, and eggplant. These molecules have a special property that causes them to change color based on the pH. When the citric acid dissolves, the pH shift causes the drink to become more acidic (lower pH); this causes the anthocyanins, which start out purple, to change their structure slightly, and thus appear beautifully pink!
So, if you’re sipping this exciting new concoction while you scroll through the comments from all your jealous Instagram followers, remember… you have chemistry to thank! It’s not magic, it’s science (so don’t eat the pseudoscience)!
Hailing from central California, John is a PhD candidate (Update: he did it! Dr. Frelka to you!) at Ohio State University studying how processing affects the physical properties of different food products. John has a B.S. and M.S. in Food Science from UC Davis where he studied both consumer food science and food microbiology. As a self-proclaimed nerd, John spends his free time reading comic books and playing board games. According to John, the major food groups are coffee, beer, and buffalo chicken dip. (Follow him on Twitter! @madfoodscience)