All About Asparagus
What is it? The word asparagus is originally derived from the Persian word for "sprout" or "shoot," which characterizes the short, edible stems of the Asparagus officinalis plant. Though the stems are edible, if asparagus are allowed to flower and fruit the small red berries are poisonous to humans. Only young asparagus are typically eaten, as older plants quickly develop a woody texture and strange flavor. Asparagus is one of the oldest known edible plants in human history, with pictures of it found in Egyptian ruins dating from 3000 BC. A recipe for asparagus is also present in the oldest surviving cookbook from 300 AD. Though the most common asparagus are green, white and purple varietals are also popular. White asparagus, also known as spargel, is mostly found in Germany and parts of northern Europe. It is cultivated by sheltering the sprouts from light, thereby preventing photosynthesis. This treatment results in a more delicate texture and taste, as well as a white stalk. Purple asparagus were originally cultivated in Italy and have more sugar and less fiber than green asparagus.
Health benefits Asparagus is an excellent source of folate, a key vitamin in preventing birth defects and reducing inflammatory markers such as homocystine. It is also rich in rutin, a potent antioxidant compound thought to be beneficial in protecting against heart disease and cancer. Rutin has also been shown to protect small capillaries, indicating that it may help in preventing unsightly spider veins, though this has yet to be confirmed in human studies. Asparagus is also rich in the amino acid asparagine, which was named because of its abundance in the plant. Asparagine is essential for the functioning of the nervous system. While not technically a benefit, biochemically speaking asparagus is most famous for its aromatic effects in the powder room. Asparagus digestion results in the rapid production of a handful of sulfur-containing compounds that give urine a strong and unpleasant stench, similar to cooked cabbage. Though not everyone can detect the scent of asparagus in urine, science suggests that most, if not all, people produce it. There is no report of negative health effects from these sulfur compounds.
Sourcing and storage Asparagus can be found at grocery stores and local farmers' markets from early March through early May in San Francisco, and tends to run $3-$6 per bunch. Asparagus is generally chosen based on the thickness of the stem. Young, thin-stemmed asparagus tend to have a more delicate texture and be more aromatic. Young asparagus are more rich in the sulfur compounds that impact post-digestion odors, so if you're particularly sensitive to these smells you may opt for the larger, more mature asparagus plants. Asparagus stores nicely when kept dry in the refrigerator for 1-2 weeks. However, the antioxidant potential does decline once asparagus are harvested, so from a health perspective fresh asparagus are preferable.
At home Cooking asparagus can be tricky due to the rapid transition between the woody asparagus stem and the tender stalk. For ideal asparagus tenderness, grip a fresh asparagus spear with two hands--one in the middle and one closer to the bottom end--with thumbs pointing toward each other. Quickly snap the asparagus in two; this should break the stalk at a point that removes the most tough and stringy part of the vegetable. Alternatively the asparagus stem can be peeled to remove the thick outer layer. Asparagus can be eaten either cooked or raw, which surprises many people. Raw asparagus is quite sweet and tender, and makes a lovely addition to salads or served alone as an appetizer or as part of a raw vegetable platter. Some of the nutrients are better preserved in raw asparagus, though others are more available after cooking. Asparagus are delicious gently steamed or blanched, and really shine when grilled (use foil to prevent the spears from falling through the grate) or baked at high temperatures. Because of its slight bitter taste, asparagus dishes benefit greatly when paired with a splash of acid. Both balsamic vinegar and Meyer lemon juice work wonders with asparagus, as do salty cheeses such as parmesan or asiago.
Eating out To experience one of the more charming asparagus traditions in San Francisco, head to the Ferry Plaza Farmers' Market on Saturday mornings and visit the booth for Zuckerman's Farm. Zuckerman's sells more asparagus at the farmers' market than any other vendor and offers fresh deep-fried asparagus for seasonal shoppers.
This content was published in the Spring 2011 issue of Edible San Francisco Magazine. © 2011-2012 Edible San Francisco.