Well, I thought I'd share a little more about my adventures in blue food making. It turns out, there really aren't many (any?) truly blue foods out there in the natural world. I didn't want to cheat and use blue food coloring for the rainbow potluck... so I did some internet searching and reading, and came upon the Cabbage Solution!
You get a red cabbage, boil in some water for about 10 minutes. Then remove the cabbage, and boil the water for another 5-10 minutes until it is reduced. Then, you add a *pinch* of baking soda to make the liquid "basic" (as opposed to acidic). If you add too much, like I did with my first batch, the liquid gets greenish (a really beautiful teal green - which you can see in my two smaller bowls)... so proceed with caution. The liquid is really dark, so it's a good idea to work with a white dish, so that you can see around the edges what color you've created.
As you can see, it took me a few tries. My kitchen surface was covered in all different greenish blue purpley splotches. Sorta pretty... but I cleaned up anyway. :)
First, I wanted to try some blue radishes for our rainbow salad. So I took some of the cabbage dye and soaked the radishes in the dye. Honestly, as you can see, they're actually pretty purplish. But heck. At least it's purpley-blue... right? Making blue food without food coloring is hard! In the end, these weren't the most amazing success, but they definitely did the trick and represented the blue-indigo-violet end of the color spectrum quite nicely in our salad bowl!
Next, I wanted to make Blue Mashed Potatoes. But really, doesn't that look a lot more like PURPLE to you??? Why are all the foods we call "blue" actually purple foods masquerading as blue foods? It's like they have identity issues. Something is afoot!
However, I noticed that when I put the purple potatoes in the water to boil them, the water instantly turned teal-greenish. Can you see that? It was really beautiful - and reminded me exactly of the teals and purples that I experienced with the cabbage. Science!!
In the end I added all my blue cabbage "dye" to the mashed potatoes as the liquid (along with some almond milk). You can see the color of potatoes up on my plate. Honestly, I still think they really look purple, but - you know what, I'm okay with that. Mostly, it was just blowing my mind that you could make something edible and delicious turn out with that vivid color, 100% naturally! The color was downright freaky and beautiful. I think it would be a really fun thing to do for kids... I mean who doesn't want to eat mashed potatoes that color!!??