This year at Dandelion Farm (a.k.a. Our garden), we planted purple beans! I have been quite pleased- they are pretty plants with lovely purple and lavender blossoms. Little Bear has enjoyed watching the plants twine up the poles we set up, and the beans are easily spotted by four year old eyes due to the contrast with the green leaves.
We had our first bean harvest this week: 
Are these not gorgeous? Note that some are partially green- these seemed to be the ones more shaded by the leaves.
Little Bear is usually pretty keen to be my sous chef, so he helped snap and cut the beans. We cooked them very simply, just boiled with a little salt for 4 minutes.
After about 2 minutes, the beans began to look different in the pot, and by the time they were done, this is what we had:
Wow. The color change was so dramatic and fast that it met with whole-hearted approval from Little Bear, who watched the pot with rapt attention during the lprocess. What a good opportunity to talk about science!
For those who are interested, what is going on here is that compounds called anthocyanins give these beans their special color. Anthocyanins are sensitive to heat and pH changes- cooking degrades the anthocyanins and allows the 'base' color of the chlorophyll to shine through. Voila, green bean.
I have some ideas for the next bean harvest:
-Partially dip some beans in boiling water so they are half-and-half green and purple
-Have a taste test (with Little Bear) to see if there is any difference between cooked green and raw purple beans
-Change the pH of the water to observe any difference in cooked bean color
-Make a bean salad with lemon juice to see if cooked beans might regain some purple color!
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