Just as with everything else, there are trends and fashions at the farmers market. Year before last it was cardoons. Last year it was kohlrabis. Now those are old hat. This year one of the new items is black haricots verts. Actually they’re not black but a very deep shade of purple that looks black. The beans are very distinctive, heaped up in baskets next to the regular green pole beans. It’s very hard to resist buying some if you are looking for something a little different to try out.
Many of you experienced cooks probably already know this, but I was surprised and more than a little disappointed when I dropped the beans into boiling water to blanch them, and the purple/black color disappeared. Suddenly my haricots verts were, indeed, green.
Curious to know why that happened, I turned to the most reliable expert on kitchen science that I know, Harold McGee, author of a regular column in the New York Times and numerous books including On Food and Cooking: The Science and Lore of the Kitchen (Second edition, Scribner, New York, 2004). Sure enough, there he had a short scholarly discussion of anthocyanins (pp. 267-268, 281-281) It turns out that the red and purple colors of most flowers and vegetables are due to a group of about 300 related chemicals known as anthocyanins. They are very sensitive to alkalinity and acidity as well as some metals, which help to determine the color that the chemical gives to a flower or vegetable. They are also highly water-soluble, so when the spaces where they are stored break open during the cooking process, the coloration is rapidly diluted and dissipates. Hence, the beautiful black beans turn a beautiful chlorophyll-green. And that’s ok, too, because the blanched haricots verts can be used for whatever might be one of your favorite dishes.
I decided to use them in a chilled salad with scallions and dill, topped with a balsamic vinaigrette. The bright green chlorophyll color was terrific.
Haricots Verts Vinaigrette with Scallions and Dill
- 1 pound fresh haricots verts, washed and trimmed
- 4 scallions cut in ½ inch slices, whites and greens included
- ¼ cup fresh dill fronds, coarsely chopped
- 1 tablespoon white wine vinegar
- 1 tablespoon balsamic vinegar (not the expensive stuff)
- 1 clove garlic, peeled and minced
- 2 teaspoons Dijon mustard
- salt and pepper
- pinch of sugar
- 6 tablespoons extra virgin olive oil (the good stuff)
- In a large pot, bring 2 quarts of salted water to a rolling boil
- Add the green beans in a single batch and return the water to the boil
- Boil the beans for no more than 4 minutes so that they remain crisp. Drain and immediately plunge into a prepared large bowl of ice and chilled water.
- When the beans have cooled, drain and transfer them to the refrigerator until they are ready to use. (Remove any remaining pieces of ice)
- Prepare the scallions and dill. Set aside.
- Using a whisk and a small bowl, combine the vinegar, minced garlic, mustard, salt, pepper, and sugar.
- Whisking continuously, slowly stir in the olive oil to make a vinaigrette. Correct the seasoning.
- In a large bowl, combine the haricots verts, scallions, and dill. Dress with the vinaigrette to suit your taste. Adjust the seasoning. Chill, tightly covered, in the refrigerator for an hour to let the flavors blend.
- Serve alone or on lettuce leaves.