There is also a whole group of beans with red-streaked pods and similarly red-mottled seeds that are especially tasty and easy to shell at this stage; the group includes French horticultural beans, Italian borlotti beans and varieties such as Vermont Cranberry and Tongues of Fire. Many are bush beans, meaning a single planting matures in a few weeks.
In my garden I love to experiment with any bean at the "shelly" stage, even if they are being grown for their young pods or for drying. Recently I picked a few pounds of scarlet runner bean pods from plants that were gracing my trellis with their striking red flowers. The still-green pods, unlike dried ones, were impossible to pry open, but slicing the flat seams with a knife made the job go quickly.
As the seeds dropped into my bowl, it was fascinating to see the stages of metamorphosis. The youngest, smallest ones were cream, barely coloring to rose. At the next stage they were larger and a brilliant shocking pink. At their largest, a mottled navy-blue speckled pattern crept over one side of the seed, surrounding the eye. And finally, in a few pods that had dried completely, the seeds had reached their mature coloration of deep blue-black with specks of magenta. It was like watching a sunset. At any stage, alas, the anthocyanins that account for the gorgeous pinkness dissolve when cooked, and the beans, though still fine to eat, fade to a lavender-gray.
I was pleased to find thatmy Kentucky Wonder beans, an old-fashioned pole bean favorite, made excellent shell beans. Their seeds were whitish, on their way to becoming a mature brown, and their pods opened with less resistance than those of the runners. Like most shell beans, they took up to 20 minutes of slow simmering to soften. Drained and dressed with a few chopped fresh tomatoes, a bit of minced fresh sage, coarse salt and a generous squirt of olive oil, they made an excellent room-temperature salad, more Italy than Kentucky. And wonderful.