Ginger - production & trade

India is one of the prime producers of ginger. From pots in gardens to large-scale, mechanised operations, it is cultivated on a local and commercial scale. In 2003, India grew over a quarter of a million tonnes of rhizomes - almost three quarters more than thirty years ago. It is grown on a smaller extent in Bangladesh and Pakistan. In India there are at least 400 different cultivars, each with varying properties such as the level of potent ginger oil.

Cultivation

Ginger is usually cultivated vegetatively, which means pieces of rhizome are planted in the soil and each sprouts to form a new plant. Modern micropropagation is also being used where new plants are cloned from cells taken from a plant. The cloned offspring are then planted out in fields.

Harvesting

Rhizomes are harvested at different times, depending on their intended use. Fresh ginger might be harvested about 5 months after planting. For preserved ginger, they are usually dug up 5 to 7 months after planting, before they are fully mature but while they are still tender and mild. For dried ginger, mature rhizomes with a full aroma, flavour and pungency are harvested 8 to 9 months after planting. The essential oil content within rhizomes increases with age, so plants used for this might be harvested even later. They are harvested either by hand or by mechanical diggers and are graded according to local preference or end-use. They are sold fresh, dried or ground, or are processed into oil and oleoresin.

Processing

Photograph of ginger rhizomes from Kews Economic Botany Collection.
Image: Ginger rhizomes before peeling or processing.

The most familiar form in Europe is dried ginger. Its preparation involves killing the rhizomes in boiling water, or by peeling, scraping or slicing, and drying. Rhizomes that have been peeled are known as 'uncoated' or 'white' ginger. Those with the peel still on are known as or 'black' or 'coated' ginger. Both are usually sun dried for several days. Dried rhizomes can be pulverised to produce ground ginger.

Ginger oil and oleoresin can be obtained from fresh or dried rhizomes. Ginger oil is obtained by steam distillation, and oleoresin is extracted with organic solvents. Black ginger is preferred for these extractions. India is one of the top producers of ginger oil, and exports mainly to America and Europe.