Asparagus is native to the eastern Mediterranean region and also northern and southern Africa. It is now grown all over the world and available year round. There are over 300 varieties of asparagus with only about 20 of them edible.
Most American asparagus is of the green variety, while white is the preferred variety in most of Europe. White is grown underground to inhibit the development of chlorophyll content and impart a more delicate flavor. The French are artful in their blanching of green varieties such as 'Argenteuil' to get aesthetically appealing white spears.
A member of the lily family, asparagus is one of the few vegetables grown as a perennial. It is usually harvested in the spring, April being the prime month, when it is 6 to 8 inches tall. The shoots not cut become fern-like foliage plants 3 to 5 feet high. Asparagus is dormant in the winter.
When selecting asparagus, look for those that are firm and the tips closed. The darker stalks usually have the higher concentration of nutrients. After purchasing and if not using right away, store in the refrigerator with ends wrapped in a damp paper towel. Use within a day or two as nutrients as well as flavor lessen in time.
To prepare: Under cold running water, scrub with a vegetable brush. Snap off the tough ends of the asparagus by holding the spear in both hands and bend, making it break where the tougher and tender parts meet. Lightly steam the entire spear or, if stir frying, cut the spear diagonally. Leftovers work well for a breakfast or brunch omelet.
Do not cook asparagus in an iron pot because of tannins in the asparagus. They can react with the iron and cause an unappetizing discoloration.
After cooking, asparagus can be served hot or cold. If serving cold, place stalks in cold water right after cooking and then remove them again quickly. Keeping them soaked will turn them soggy.
To roast asparagus, mix with a vinaigrette, herbs, and spices. If adding other vegetables, make them thinly sliced to insure they'll match the short cooking time of asparagus. Roast at 400 degrees for 10 minutes.
Asparagus is a nutritional wonder. It is low in calories but rich in protein as compared to most vegetables. It contains potassium, vitamins C, A, K, riboflavin, thiamin, folic acid, and niacin. Its ratio of potassium to sodium is excellent. It also contains iron and provides fiber.
The Egyptians long ago discovered its therapeutic properties. Historically, it has been used as a diuretic and also in the treatment of arthritis and rheumatism.