Ginger processing
Practical Action
best grown in partial shade and can be incorporated as an intercrop in coconut, coffee and
orange plantations. Planting is done in April/May during the monsoon rains. Ginger is harvested
by digging out the rhizomes when the tops have died down. The harvesting and processing of
dried ginger varies in different countries.
Processing dried ginger
There are two important factors to consider when selecting ginger rhizomes for processing:
a) Stage of maturity at harvest. Ginger rhizomes can be harvested from about 5 months
after planting. At this stage they are immature. The roots are tender with a mild flavour
and are suitable for fresh consumption or for processing into preserved ginger. After 7
months the rhizomes will become less tender and the flavour will be too strong to use
them fresh. They are then only useful for drying. Mature rhizomes for drying are
harvested between 8 and 9 months of age when they have a high aroma and flavour. If
they are harvested later than this the fibre content will be too high.
b) Native properties of the type grown. Gingers grown in different parts of the world can
differ in their native properties such as flavour, aroma and colour and this affects their
suitability for processing. This is most important when preparing dried ginger, which
needs rhizomes with a strong flavour and aroma. Himachel, Maran, Mananthody and
Kuruppampady are good varieties for the preparation of dried ginger. Size of rhizome is
an important factor to consider when drying ginger – medium sized rhizomes are the
most suitable for drying. Large rhizomes often have a high moisture content which
causes problems with drying.
Making dried ginger
Dried ginger is available in a number of different forms – the rhizomes can be left whole or they
may be split or sliced into smaller pieces to accelerate drying. Sometimes the rhizomes are
killed by peeling or boiling them for 10 to 15 minutes, which causes the rhizomes to become
blackened. They have to be whitened (bleached) by treating with lime or sulphurous acid. The
only product which is acceptable for the UK market is cleanly peeled dried ginger.
The process for dried ginger:
The fresh rhizome is harvested at between 8 to 9 months of age.
The roots and leaves are removed and the rhizomes are washed.
The rhizomes have to be ‘killed’ or inactivated. This is done by peeling, rough scraping or
chopping the rhizome into slices (either lengthwise or across the rhizome). The skin
should be peeled off using a wooden scraper made from bamboo to prevent staining the
rhizome. Whole unpeeled rhizomes can be killed by boiling in water for 10 minutes.
After peeling and washing, the rhizomes are soaked for 2-3 hours in clean water then
soaked in a solution of 1.5-2.0% lime (calcium oxide) for 6 hours. This produces a
lighter coloured (bleached) rhizome. After soaking, the rhizomes are drained.
The rhizomes are dried. The traditional method is to lay the pieces on clean bamboo
mats or on a concrete floor and sun-dry until a final moisture content of 10%. Drying
may take anything from 7 to 14 days depending upon the weather conditions. During
drying, the rhizomes lose between 60 and 70% in weight.
In rainy conditions, a mechanical drier such as a tray drier should be used to accelerate
the drying process. Sliced ginger pieces take only 5-6 hours to dry when a hot air drier
is used. Whole peeled ginger rhizomes take about 16-18 hours to dry in a mechanical
drier. It is important to monitor the air flow and temperature during drying. The drying
temperature should not exceed 60°C as this causes the rhizome flesh to darken. See the
Practical Action Technical Brief on drying for further information on the different types
of drier available.
After drying, the rhizomes are cleaned to remove any dirt, pieces of dried peel and
insects. An air separator can be used for large quantities, but at the small scale it is
probably not cost effective.
The dried rhizomes should be packaged into air-tight, moisture proof packaging for
storage or export.
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