Getting Back to Ginger’s Roots

As one of the world’s most-popular spices, ginger’s usage is wide and varied, from the characteristic flavors in ginger ale to the essential sushi condiment. Ginger can not only be used as a culinary flavoring for foods and beverages, but it has also historically served as a medicinal agent for numerous ailments, particularly those associated with nausea and inflammation. Traditional Chinese medicine uses fresh ginger to alleviate fevers, headaches and muscle aches.

So it grows

Although it originated in Asia, ginger (Zingiber officinale) has spread throughout tropical and subtropical regions, including India, the Middle East, Africa and the Caribbean. China is a key growing region for ginger. Not long ago, Jiangsu was an important province for ginger-oil production. However, production has shifted to the Shandong and Anhui provinces, which are now responsible for 90% of China’s ginger manufacture, because the land and climate there are more suitable.

Although often called a root, ginger is a rhizome, a thick, fibrous, horizontal underground stem covered by a thin, brown-colored skin when mature. It is propagated from roots, not seeds. In the spring, farmers plant a small piece of root with a growth spur, which sends up green, leafy stalks that reach between 12 and 40 in. These end in a spike covered with small, aromatic yellow-green flowers. But the rhizome is the part of the plant used for the spice we know as ginger.

To harvest, farmers lift the entire root. Harvest occurs in fall, so cold weather means the root cannot be dried immediately. Some of the root is sold immediately to spice dealers, and the rest is stored in underground pits and covered with soil. Growers in Shandong, the biggest ginger-producing province in China, store ginger root in 32-ft.-deep pits supported by concrete cylinders. The root is retrieved from this underground storage and graded in the spring of the following year. Good-quality roots are used for the fresh-spice market or for replanting. If the root is unsuitable for selling dried, it is processed into oil.

The essentials of ginger

Ginger’s flavor is characterized by warm, spicy and woody notes, with slight citrusy notes. The key to ginger’s refreshing, pungent—yet warm—taste is its oleoresin, gingerin. Depending on the age of the harvested rhizome, ginger contains between 1% and 3% essential oil, which has a sweet, citrus aroma. The more-mature rhizomes produce a fuller aroma, flavor and pungency than their younger counterparts.

Ginger essential oil is derived from the powder of crude ginger flakes made from roots dried in the sun for one week. The powder is placed in large stills that hold 1,322 lbs. of powder. The yield from these stills is approximately 1.6%, so one charge produces about 22 lbs. of oil. The distillation uses steam generated by a coal-fired boiler for up to 24 hours to ensure key high-boiling components are extracted.

Ginger essential oil consists mostly of mono- and sesquiterpene hydrocarbons. Some of the compounds present include a-pinene, camphene, B-pinene, 1,8-cineole, linalool, borneol, y-terpineol, nerol, neral, geraniol, geranial, geranyl acetate, B-bisabolene and zingiberene. Gas-liquid chromatography has been used to measure the varying levels of the main compounds in ginger essential oils from India and China. Ginger oils from these two sources are close in composition; however, Indian oils generally contain slightly higher levels of linalool and beta sesquiphellandrene than Chinese varieties. This might be a result of differences in the freshness or dryness of the root from which the essential oils were derived. The exact composition of ginger may also vary depending on geographic origin, maturity at harvest and climate.

One spice, many guises

In addition to essential oil, ginger can take many other forms. Over the years, ginger has shown itself to be a highly versatile spice and is used in different ways across the world.

Fresh ginger is an essential flavoring ingredient for many Asian dishes, where it confers a fresh, peppery flavor and spicy aroma. It can be minced, crushed, grated, sliced or chopped. Once cooked, however, fresh ginger is milder in flavor and less pungent. Fried ginger is often used in Chinese and Indian cuisines, in dishes such as stir-fries and curries.

More aromatic and less pungent than fresh, dried ginger is a spice commonly found in the West. It is often used in baked goods, most notably gingersnaps and gingerbread, as well as in puddings, preserves and soft drinks, including ginger ale and ginger beer.

Pickled ginger is a popular accompaniment in Asian cuisine. In Japan, ginger is pickled with vinegar (and known as gari and beni shoga), often dyed red or pink, and served with sushi.

Preserved ginger, or “stem ginger," is another form of ginger that is preserved in syrup and is most often added to cakes and puddings. However, it can be eaten on its own as a spicy treat, as can crystallized ginger (ginger cooked in syrup and rolled in coarse sugar).

Natural flavors can also be derived from ginger as distillates. This type of ingredient can impart the distinctive aroma of freshly grated ginger, but without the tingling heat associated with ginger oil.

The world over, ginger is considered a valuable spice for many purposes. Its characteristic aroma adds distinctive notes to a multitude of food and beverage systems.