A cultivated member of the lily family, tender green stalks of asparagus signal the arrival of spring. While green asparagus is most common, asparagus can also be white or purple. White varieties are mounded with soil to keep sunlight out; because the spears develop in darkness, they don't produce chlorophyll, so they never turn green. Their skin is slightly tougher and their flavor is milder. Purple asparagus, a relative newcomer, is an attractive alternative to green. But unless you apply vinegar or lemon juice to the spears before cooking, they will discolor. Truly versatile, asparagus is delicious steamed, roasted, sauteed, and grilled. Its sweet, slightly nutty taste goes well with all kinds of flavorings, including delicate herbs, citrus, garlic, ginger, sesame oil, hard grated cheeses, eggs, mushrooms, ham and bacon, cream, and shellfish, particularly shrimp.
Asparagus: Color Key
There are approximately 300 species of asparagus plants within the Asparagus genus, but we eat just one: Asparagus officinalis. While the green variety is most common, purple and white asparagus can also be found in some farmers’ markets and specialty stores.
Its sweet, grassy notes become more vegetal with age. Although it’s available in supermarkets much of the year, it’s best consumed from early to late spring, when it’s more likely to be harvested from a local source.
It’s sweeter, tenderer, and produces fewer stalks per plant than its green cousin. Also known as Violetto d’Albenga, this variety originated in northwestern Italy (these days, it’s also grown in California). To preserve its color, use it raw or cook it briefly; the longer it cooks, the more likely it’ll turn from purple to green.
Milder than other varieties, it has just a touch of pleasant bitterness. White asparagus is buried in the soil and kept out of the sun to prevent it from developing chlorophyll, which would turn it green.
1 lb. fresh = 12 to 20 spears (depending on size) = about 3-1/2 cups chopped
Although asparagus is available much of the year, its true season lasts only a few glorious weeks in April and May. Commonly sold in bundles of about one pound, it's often displayed standing upright in a tray of water. Choose fresh-looking, firm, straight, and smooth spears with tight tips. Check the cut ends of the stalks; they should be moist, not dried out. Stalks should not be dry at the cut ends or limp. Open tips or ridges along the stem indicate old age; these stalks will be less flavorful and have a tough, woody texture.
Although some cooks think that pencil-thin asparagus is tenderer than fatter spears, this isn’t necessarily the case. Both can be tender, but it’s the beefier spear that usually has a better texture. No matter its size, each spear has a set number of tough fibers that run its length. In a skinny spear, those fibers are crammed together, with less juicy flesh between them. In fatter spears, those fibers are further apart, separated by more sweet, tender flesh. But asparagus of any size can be sweet and tender as long as it's fresh.
To prepare spears for cooking, trim away the tough, white woody base from the end of the asparagus spears. To ensure you’ve trimmed enough, cut off a sliver of the end and eat it: It should be tender. You can also snap off the bottom of the spear with your hands (it should break naturally where the stem starts to toughen), though you’ll probably waste more tender asparagus than necessary. If the asparagus is thick-skinned or fibrous (take a small bite to test), peel the spears from just under the head to the stem end. Use the fibrous ends for stock or for your compost pile.
Stand asparagus bundles upright in about an inch of water or in a jar or a shallow tray. Cover with a plastic bag and store in the refrigerator for up to three days. Cook asparagus within two days for the best flavor.