Brussels sprout

The Brussels sprout is a cultivar of wild cabbage grown for its edible buds. The leafy green vegetables are typically 2.5–4 cm (0.98–1.6 in) in diameter and look like miniature cabbages. The sprout is Brassica oleracea, in the "gemmifera" group of the family Brassicaceae. Although named after the city in Belgium, few historians believe the plant originated there.

Cultivation
Forerunners to modern Brussels sprouts were likely cultivated in ancient Rome. Brussels sprouts as we now know them were grown possibly as early as the 13th century in what is now Belgium. The first written reference dates to 1587. During the 16th century, they enjoyed a popularity in the southern Netherlands that eventually spread throughout the cooler parts of Northern Europe.

Brussels sprouts grow in heat ranges of 7–24 °C (45–75 °F), with highest yields at 15–18 °C (59–64 °F). Fields are ready for harvest 90 to 180 days after planting. The edible sprouts grow like buds in a spiral along the side of long thick stalks of approximately 60 to 120 cm in height, maturing over several weeks from the lower to the upper part of the stalk. Sprouts may be picked by hand into baskets, in which case several harvests are made of 5 to 15 sprouts at a time or by cutting the entire stalk at once for processing, or by mechanical harvester, depending on variety. Each stalk can produce 1.1 to 1.4 kg, although the commercial yield is approximately 900 g per stalk. In the home garden, "sprouts are sweetest after a good, stiff frost."

Brussels sprouts are a cultivar of the same species that includes cabbage, collard greens, broccoli, kale, and kohlrabi; they are cruciferous. They contain good amounts of vitamin A, vitamin C, folic acid and dietary fibre. Moreover, they are believed to protect against colon cancer, because they contain sinigrin. Although they contain compounds such as goitrin that can act as goitrogens and interfere with thyroid hormone production, realistic amounts in the diet do not seem to have any effect on the function of the thyroid gland in humans.

Europe
In Continental Europe, the largest producers are the Netherlands, at 82,000 metric tons, and Germany, at 10,000 tons. The United Kingdom has production comparable to that of the Netherlands, but it is not generally exported.

North America
Production of Brussels sprouts in the United States began in the 18th century, when French settlers brought them to Louisiana. Thomas Jefferson grew them at Monticello. The first plantings in California's Central Coast began in the 1920s, with significant production beginning in the 1940s. Currently there are several thousand acres planted in coastal areas of San Mateo, Santa Cruz, and Monterey Counties of California, which offer an ideal combination of coastal fog and cool temperatures year-round. The harvest season lasts from June through January. They are also grown in Baja California, Mexico, where the harvest season is from December through June.

Most of the United States production is in California, with a smaller percentage of the crop grown in Skagit Valley, Washington, where cool springs, mild summers and rich soil abounds and to a lesser degree on Long Island, New York. Total United States production is approximately 32,000 tons, with a value of $27 million. Ontario, Canada produces approximately 1,000 tons per year.

80% to 85% of US production is for the frozen food market, with the remainder for fresh consumption. Once harvested, sprouts last 3 to 5 weeks under ideal near-freezing conditions before wilting and discolouring, and about half as long at refrigerator temperature. American varieties are generally 2.5 - 5 cm in diameter.

Nutritional and medicinal value
Brussels sprouts, as with broccoli and other brassicas, contains sulforaphane, a chemical believed to have potent anticancer properties. Although boiling reduces the level of the anticancer compounds, steaming, microwaving, and stir frying does not result in significant loss.

Brussels sprouts and other brassicas are also a source of indole-3-carbinol, a chemical which boosts DNA repair in cells and appears to block the growth of cancer cells.

Cooking and preparation
The most common method of preparing Brussels sprouts for cooking begins with removal of the buds from the stalk. Any surplus stem is cut away and the surface leaves that are loosened by this cutting are peeled and discarded. Cooking methods include boiling, steaming and roasting; however, boiling results in significant loss of anticancer compounds. To ensure even cooking throughout, buds of a similar size are usually chosen. Some cooks will make a single cut or a cross in the centre of the stem to aid the penetration of heat.

Whatever cooking method is employed, it is important not to overcook them, which will render them gray and soft. Overcooking releases the glucosinolate sinigrin, which has a sulphurous odour. The odour is the reason many people profess to dislike Brussels sprouts, having only ever tried them overcooked. Generally, six to seven minutes boiled or steamed is enough to cook them sufficiently.