There's a chemical reaction that happens in your cake batter that makes red velvet cake red! No red coloring added? Science...I love it!! I asked a friend, "Do you know what really makes red velvet cake red?", waiting for her to not have an answer to my question. Her response, "Beets, right?" Oh...yeah. Well, there's that. There are recipes out there that use beet juice as a more natural way to enhance the red coloring of the cake, but that's not a science experiment.
The science here is a reaction between cocoa powder and the acids in your recipe. The result should be a reddish hue. I was always so proud that I knew this, and I would shock people all the time with this trivia. However, I never really knew how it all worked. I told myself I would research this one day, and I finally did just that. I gathered all
of my information, and then turned my pastry workstation into my science lab to test out what I had learned. I wanted to see if my batter would really be red!
One key ingredient to use is natural cocoa powder, not dutch-processed cocoa. Natural cocoa powder is acidic and contains compounds called anthocyanins, which are red in color and can be found in other plants and foods, e.g. pomegranates, red cabbage, roses and red wine. Anthocyanins are special because they are pH sensitive. They are bright red in a very acidic state, but can turn brown in a more alkaline environment. Dutch-processed cocoa is natural cocoa that has been washed with an alkaline solution, giving it a darker brown color. Since the dutch-process neutralizes the cocoa, leaving it no longer acidic, you won't be able to get the red color that you can with natural cocoa.
Ben Starr www.benstarr.com
REAL Red Velvet Cake (with no food coloring or beet juice)
Other necessary ingredients are your acids: buttermilk and vinegar. Baking soda works with both of these acids as a leavening agent in your cake, and the reaction of vinegar and butter- milk helps to better reveal the red anthocyanins in the cocoa.
Once I got to mixing my cake, I was anxiously anticipating a bright red color to show through the batter. I added my dry ingredients, including the natural cocoa and baking soda, and then followed up with the vinegar and buttermilk; fingers crossed. There wasn't a huge reaction and burst of fiery red, but the batter did turn a more faint reddish-rust color. If I were to have baked my experimental batter as is, any red-rust tint may not have been noticeable. In the end, I added just a drop or two of red food coloring to obtain the red that everyone expects to see.
Not only is baking an art, but it's definitely a science too! I'm positive that I could do more experimenting with my recipe by altering the amounts of natural cocoa and the acids to get a better reaction. I came across a blogger that experimented the same as I did. His picture poses a red velvet cake with no added coloring or beets next to a chocolate cake that used dutch-processed cocoa. You can notice red hues when sitting alongside the chocolate, but the cake might look brown, when standing alone, to someone who has only witnessed the gleaming red of added food coloring.