Most colors can be created relatively easy with veggies and fruits, but blue always seems to be a problem. When searching on the internet for some solutions I read something about making a natural blue color with red cabbage and baking soda. To me this sounded a bit weird and it did not seem credible to me. But it made me curious so I gave it a shot this week!
So I have done it this week and it is actually not that hard at all. The lead time for making this blue coloring is somewhat long, but most of this time consists of waiting while your pot is boiling.
Furthermore, for this recipe you only have to use two very cheap ingredients - red cabbage abd baking soda - which gives you about 1/2 cup of blue coloring that you can use for days when you keep it in the fridge!
Chop up a complete red cabbage.
Put the cabbage in a large pot with enough water to cover it.
Boil the cabbage 15 mintues and strain it out. Save the purple water and put it back in the pot.
Reduce the purple liquid to around 1/2 cup, so that the color gets more intense. It took me 80 minutes to reduce it.
Let the liquid cool down and transfer it to a glass jar. I used a glass so that I was able to see the color change.
At first, add 1/8 teaspoon of baking soda and stir well. If it bubbles up, it is better to let the bubbles subside. Repeat this step until the color turns from purple to blue. Try not to exceed 1/2 teaspoon in total, because ohterwise it will taste salty.
You can test the color by putting it in a glass with soy or almond milk, since it is easier to see if the color is right in a white liquid. If it is still purple, add a little bit more baking soda. If it is turning towards green, you added too much. In this case you can add a little acid to bring it back to a blue color.
Store the liquid in the fridge for up to 2 weeks and use it in smoothies, smoothie bowls, cakes and other kinds of food you want to color blue.