These color-changing food colorings come in three varieties and are created from naturally-occurring foods that contain special pigments that can change in different pH environments.
In other words, all you need are a few food items that contain colored pigments, and other substances that will cause a color change altering the pH of that food item.
The most special colors were obtained from butterfly pea flowers, commonly used to make tea, and red cabbage, which were found to contain pigments called anthocyanins. Anthocyanins are rich in antioxidants, but they have a particularly intriguing property — their color is pH dependent. In an acidic environment, they are pink or red, and in an alkaline environment, they turn, a delightful shade of blue!
Interested? Here are a few ways you can extract food coloring from red cabbage and butterfly pea flowers:
1. You can juice the red cabbage leaves
The easiest and most accessible way to getting your natural food coloring. Simply juice the fruit or leaves (leafy veggies), which is, in this case, red cabbage for instant food coloring. If you want a longer lasting coloring, however, mix in some alcohol to act as preservatives.
2. You can steep the leaves in alcohol or glycerin
Steep the dried flowers or the cabbage leaves in alcohol to extract the coloring from them. Let this sit overnight and then filter out the flowers and leaves.
Now, to observe that magical change in the food coloring, all you have to do is add an alkaline or acidic substance that won't do very much to alter the quality of any recipe it is added to. The perfect examples are baking soda (alkaline) and lemon juice (acidic).
A few drops of these substances and you'll have the most beautiful results. The DIY food coloring can be added to any recipe so don't be afraid to experiment!
Here's a step-by-step recipe authored by Tracy Ariza, DDS:
Prep Time: 10 minutes infusion and straining time (optional): 3 hoursTotal Time: 3 hours 10 minutes
Servings: 16 tsp.
For blue coloring:
1 Tbsp. butterfly pea flowers or 1 tsp. of the powder
For purple coloring:
2 red cabbage leaves
For extracting the colors:
1/3 cup vodka or other high proof alcohol, or glycerin
Choose one of the colorant choices above and one of the extraction ingredients (alcohol or glycerin).
When using fresh cabbage leaves:
Either cut the leaves into small pieces or juice them. Add the pieces to a small bottle or jar with enough alcohol to fully cover them. If using juice, mix the juice with alcohol to dilute the color and help preserve your coloring. (The final alcohol concentration should be over 20% for safe preservation.)
After steeping for several hours, the plant material can be strained out by pouring the mixture through a cloth or coffee filter.
When using dried flowers or powders:
Mix together either butterfly pea flowers or one of the powders (a powder made from the flowers or dried cabbage leaves) with some alcohol or glycerin. (Water can also be used if you aren't concerned with preserving the homemade coloring.)
The mixture can be used as-is immediately or allowed to steep for several hours. After steeping, the powders can be strained out with a cloth or coffee filter (or it can be used without straining). Straining may lighten the color of the coloring. Experiment to find the look that works best for your project.
Colorings made without alcohol or glycerin should be stored, lidded, in the refrigerator and used within 5 days.
If the alcohol concentration is high enough (over 20%), you can keep your coloring for longer. Then, all you have to do is transfer the liquid into small bottles and store in a cool, dry place for up to several weeks. (After that time, it's probably still safe to use them, but don't be surprised if the colors change!)
To preserve the colorings, make sure that the final concentration of alcohol is above 20% or that the final glycerin concentration is above 50%.
Goodluck and don't forget to have fun!