Chard and Sorrel Soup

Sorrel was a newcomer to my garden this year, so I watched it grow with curiosity.  Its seeds sprouted after the spinach and chard, but before the carrots and parsley.  Its cotyledons were tiny, oval and bright yellow-green, much like lettuce cotyledons.  Its seedlings grew more slowly than the other greens in the garden, and, by December, the sorrel plants were significantly smaller than the chard, kale, or lettuces.  But, though small, or perhaps because they have stayed small and contained for longer than the other greens, suspended at that ever so still-young state, sorrel is a very attractive green, with erect, arrow-shaped leaves that remain bright and spring-green throughout the growing season.

Sorrel (Rumex acetosa) in the garden

What I didn't realize about sorrel when I planted it is that sorrel is a perennial herb.  In other words, unlike the annual Brassicas and lettuces that are already getting ready to bolt, flower, and be done with their lives in one season, and unlike the biennial chard and beets that will experience spring as their second year and soon after bolt, flower, and go to seed much like the annuals, the sorrel plants are programmed to grow for many seasons, regrowing and flowering each year.  I'm not sure whether to be excited about this discovery, to run out to the garden and thin my crowded plants to an appropriate eighteen inches apart, or to be distressed by the fact that, unknowingly, I have made a long-term commitment to a row of plants that will need to be watered over the summer.  In either case, the fact that sorrel is a perennial explains why the plants have been growing more slowly than the other greens in the garden.  Sorrel is in no hurry to complete its life cycle before the summer begins.

The problem is that common sorrel (Rumex acetosa), which is native to northern Europe, Russia, Canada, and the northern United States, all of which have mild, short summers, may not be able to deal with the heat and drought that characterize our very long summer.  So my sorrel, despite its genetic programming, is probably going to lead the short life of an annual.  I still hope, though, that it will be able to flower and set seeds because now I am want to see sorrel in bloom, to see its tall, buckwheat-like flowering spikes covered in reddish-green to purple flowers and to see the shiny, brown seeds that follow.  Further inspiring my curiosity is the fact that sorrel is dioecious, with male and female flowers on separate plants, which is unusual among garden herbs.

No matter how long my sorrel plants manage to survive, their leaves are best eaten while the plants are still young.  Young sorrel leaves, which taste tangy with an after-bite of lemon, can be added to salads in small quantities, or cooked along with other greens.  The tang in the leaves comes from oxalic acid, a phytochemical found in the leaves of spinach-family plants (spinach, chard, beets), buckwheat-family plants (sorrel and rhubarb), and various other foods, including bananas, ginger, and bell peppers.  Sorrel also contains high levels of vitamins A, C, and B9, and provides some iron, potassium, calcium, and magnesium.  Used as an herbal supplement, sorrel is cooling, detoxifying, and a natural laxative.  Modern nutritionists warn against eating sorrel in large quantities, however, because of the high levels of oxalic acid, which can aggravate conditions such as rheumatoid arthritis, gout, and kidney stones.  Cooking sorrel helps to break down the oxalic acid before it is eaten.

Sorrel is most famous for its use in winter soups, where its lemony flavor brightens up the heavier flavors of root vegetables, onions, and winter greens.  But only a few cups of leaves are needed to add flavor to a pot of soup, which, in these, the greens-eating days at the end of winter, is simply not enough greens.  So I decided to make a chard and sorrel soup, which would contain a whole basket-load of chard along with the sorrel leaves in a potato-leek soup base.  As promised, the sorrel added a lemony tang to a satisfying winter soup.  Better yet, the flavors in the soup were even more complex and interesting the next day, when I ate the soup as leftovers. 

Chard and Sorrel Soup
adapted from Deborah Madison, Vegetarian Cooking for Everyone

Bunches of chard vary greatly in number of leaves, size of leaves, and total amount of cook-able greens.  To make this soup, I harvested approximately two large bunches of leaves.  After removing the stems and midribs and chopping the leaves into large pieces, I was able to pack a 4-quart bowl full with chopped leaves.

Fresh sorrel is difficult to find because it does not keep long once it is picked.  Sorrel is most likely to be available in the spring at the grocery store, though it may be wilted and sad-looking, or during the cool season at the farmer's market.  If sorrel is unavailable, lemon juice can be used in its place.  To substitute lemon, add the juice of one large lemon after the soup is pureed.

2 bunches chard leaves, about 4 quarts leaves (see note above)
1 bunch sorrel leaves, about 3 cups leaves (see note above)
3 medium leeks
3 tablespoons butter
5 cloves garlic, minced
2 pounds red potatoes, chopped
5 cups vegetable broth
1/2 cup sour cream
fresh cracked black pepper

Thoroughly wash the chard leaves and remove the stems and thick midribs.  Chop the leaves into large pieces.  Wash the sorrel leaves and remove the stems.

Trim the stem end from each leek and remove the outermost layer.  Slice the white and light green parts of the leek and discard the tough, dark green parts.  Soak the leek slices in water to remove soil, which tends to hide between the layers, then rinse and drain.

Melt the butter in a large pot over medium-high heat.  Add the sliced leeks and chopped potatoes and cook, stirring occasionally, about 10 minutes.  Add the garlic and cook, stirring frequently, for a minute or two longer.  Add 1/2 cup of water and scrape the bottom of the pot.  Add the greens, a batch at a time if necessary, and wilt.  Once all the greens are wilted, add the vegetable broth.  Bring to a boil, then reduce the heat and simmer for about 15 minutes.

Puree the soup in a food processor or blender – be sure to do this in small batches so that the boiling-hot soup has room to expand.  Return the soup to the pot and season with black pepper.  Stir the sour cream into the soup.  Serve hot.