native to: coastal regions of the eastern Mediterranean and Asia Minor; first cultivated in ancient Greece
in season here: April-June
Foodies will tell you to avoid asparagus thinner than your pinkie, which they describe as "grassy," because it has less flavor and is so easy to overcook. Contrary to reputation, very thin asparagus is not more tender than finger-sized stalks, as long as you break the bottoms off the stalks where they snap naturally rather than cutting them. Some argue that thick asparagus is more wasteful, to which I reply (perhaps a bit snootily) that the tough ends can be peeled, used for soup, or maybe added to smoothies, and if you're that concerned about cost perhaps you should have some nice cabbage instead. The thickness of the shoots reflects the vitality of the root; thin shoots come from roots that either are too young and should be left another year before starting to harvest or have already been harvested enough and should be left to develop their wonderful lacy fronds and regain their strength. While straight stalks are generally preferred, there's nothing wrong with a bit of curl in the tips if you're serving your asparagus cut rather than in whole spears. The curve is caused by windy conditions before harvest and makes no difference in the taste.
Asparagus is best eaten fresh, although it can be OK frozen if reheated carefully. Canned asparagus is generally not suitable for human consumption (yes, I'm being snooty again. I consider asparagus to be something of a luxury item that should be done right or not at all). Asparagus will continue to grow after picking; most vegetables do, but asparagus is particularly vigorous. Most sources recommend some variation of storing asparagus with the cut ends wrapped in a damp paper towel, but I've had better success storing them in about an inch of water, either carefully propped up in a good plastic bag or placed in a deep, flat-bottomed container with a plastic bag tucked over them.
Asparagus is a member of the lily family; there are some 300 varieties, but only about 20 are edible. Under ideal conditions, it can grow 10 inches in 24 hours. The roots should be three years old before their first harvest, but then will produce for about 15 years before needing to be replaced. White asparagus, also called blanched asparagus, is grown in trenches, with the dirt gradually filled in to keep the shoots covered so they don't develop chlorophyll; it is more expensive because of the extra labor involved. There is also purple asparagus, which is smaller and has a sweeter, "fruitier" flavor. The purple color comes from phytonutrients called anthocyanins.
Asparagus contains saponins, which have anti-inflammatory and anti-cancer properties and have been linked to improvements in blood pressure, blood sugar regulation, and blood fat levels. It also contains inulin, a prebiotic that supports good bacteria and therefore improves digestion. It's full of antioxidants, including vitamins C and E, beta-carotene, zinc, manganese, selenium, and glutathione. Other nutrients in asparagus include vitamins B1, B2, B6, and K, folic acid, niacin, choline, copper, pantothenic acid, and most of the other "usual suspects." It is a diuretic, making it a good choice for people with edema or high blood pressure, and a useful addition to a purifying or detox regimen.
Wild asparagus has long been used medicinally in Asia, particularly in India. Asparagus was first cultivated in ancient Greece, where it was used to cure toothache and prevent bee stings. It is also traditionally considered an aphrodisiac, probably because of its shape. In colonial times (and perhaps earlier) asparagus was sometimes called "sparrow grass," leading to the traditional nickname "grass" that is still used in some circles today.
Perhaps the most curious aspect of asparagus is the odor it causes in some people's urine. There appears to be some genetic basis in both the metabolism of asparagus in a way that produces the odor and the ability to smell it when present (and the two traits seem to appear independantly of each other). There is little agreement as to what substance(s) in the asparagus cause the odor, and in fact the studies have produced very different results. The odor has not been linked to any health issue, however; the only health concern with asparagus is the presence of purines, which can break down into uric acid and cause trouble for people with gout or a tendency to kidney stones.
Read more:
label-style nutrition information for raw asparagus
label-style nutrition information for cooked asparagus
Nutrition and You
MNT Knowledge Center
USDA asparagus links
*After I wrote this, I got to wondering about it and decided to test it for myself. My informal experiment showed almost exactly the same 50% loss from snapping a pound each of thin and thick stalks -- in fact, the thick stalks actually lost a statistically insignificant fraction of an ounce less. So choose the thickness you prefer and among us we'll eat it all!
Versión en español: this post is also available in Spanish.
Esperanta traduko: this post is also available in Esperanto, because Dana is a language geek.
