Processing of nutmeg & mace
Practical Action
Large number of fruits per tree ~ over 10 000 per year
Wet weight of fruits ~ over 30g per fruit
Wet weight of mace ~ over 1g per fruit
Wet weight of nuts ~ over 10g per nut.
Marcotting (splitting young trees) and grafting are also possible forms of propagation for nutmeg,
but are more difficult and less successful.
The established seedlings should be planted in a shaded area at the beginning of the rainy
season. They should be kept watered throughout the first year until they are well established.
Weeds should be kept in check by occasional slashing and the cut material can be applied to the
base of the trees in the form of mulch. Additional fertiliser is not generally applied. The
shading can be gradually removed after two to three years. Seedlings can be planted close
together so that later on when the male trees have been identified (after the first flowering) most
of them can be removed, as they do not bear fruit. Some male trees must remain for pollination.
A ratio of 1:10 is common.
Pruning helps to maintain flower, fruit and seed production. Water shoots, upright branches,
dead wood, and some lower branches can be removed.
The most threatening disease is Nutmeg Wilt in which the plant will gradually wilt and drop
leaves and fruit. There is no definitive treatment. Fruit rot has been recorded in India and a
thread blight in Grenada and Trinidad. Soil fungi will attack nutmeg trees. The main pests are
borers, or bark beetles, which are small dark brown weevils about 3mm long.
Yield depends on the size and the age of the tree. Trees will start to bear fruit from around five
to seven years old. The yield will increase considerably until the tree is about twenty-five and
then more slowly until it reaches its maximum capacity at around thirty-five to forty years of age.
Yields can be above ten thousand nuts per tree.
Harvesting
The tree starts to bear fruit when it is five to eight years old. When it is ripe, the fruit turns
yellow and the pulpy outer husk (pericarp) splits into two halves to reveal a purplish-brown shiny
seed surrounded by a red aril. Usually the fruits are allowed to split and fall to the ground before
harvesting. They should be collected as soon as possible or the underside of the fruit will
become discoloured and may become mouldy. In some areas, a long pole is used to take opened
pods directly from the tree. This ensures a better quality harvest but can also result in damage
to flowers and younger fruit.
In Grenada, there are two peak periods of production – January to March and June to August.
During these times, fruits are harvested on a daily basis. Throughout the rest of the year, fallen
fruits are collected every two to three days.
Processing
The harvested fruits are transported to a processing place. The first thing to do is separate the
mace (aril) from the rest of the seed. The fruits are opened by hand and the scarlet aril (mace)
surrounding the nut is removed by cutting with a small pointed knife the attachment of the mace
to the base of the nut (nutmeg). Care needs to be taken to avoid damage to the nut. An
alternative method of shelling the nuts is to tip them onto a sloping cement floor from a height
of three to four metres. Another option is to soak the nuts in water for four to twelve hours and
then squeeze between the thumb and forefinger until the nut pops out.
Mace
Mace is the thin lacy material covering the kernel and represents only a small fraction of the
weight of the kernel. For each 100kg of nutmeg, there is only 3-3.5kg of mace. The quality of
mace depends on the amount of volatile oil. Mace is available in the market as whole, broken or
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