Processing of nutmeg & mace
Practical Action
ground types.
The separated mace is flattened by hand and dried on mats in the sun. This takes between two
and four hours. Grenadian mace is cured by storage in the dark for four months. This produces
a brittle, pale yellow mace that attracts a premium price and is graded according to size, the
bigger the mace, the better the premium. After grading, the mace can be classified and bagged.
Commercial mace consists of flattened lobed pieces, 2.5cm long and about 1mm thick. It has a
similar taste and aroma to nutmeg, but is more delicate. There are four different types of
nutmeg:
Banda mace – considered to be the finest. It has a bright orange colour and fine aroma
Java Estate mace – this mace is golden yellow interspersed with bright red streaks
Siauw mace – this mace has a lighter colour than Banda mace and less volatile oil
Papua mace – contains very little volatile oil (the oil that it contains has a pungent
aroma). It is not suitable for distillation.
Nutmeg
Green nutmegs are sorted to remove any broken, discoloured, rotten, water logged or mouldy
seeds. The nutmegs are spread out to dry in the sun in their shells. They are turned each day to
prevent fermentation. The nutmegs are sufficiently dry when they rattle inside the shell. The
drying time depends on the external temperature, humidity and air flow across the nutmegs, but
generally takes about one week. Sometimes artificial dryers are used to speed up the process.
To produce shelled nutmegs, the dried seeds are cracked by tapping the end of the nuts with a
small wooden mallet. If the nuts are tapped on the side there is a possibility that the kernel may
be bruised. Cracking the shell is often done by a centrifugal type of machine. The nuts are
forced against the inside of the drum which causes the shell to crack.
After cracking the shells, the nuts are sorted. Whole kernels are separated from the broken
pieces of kernel.
Quality control and grading of nutmeg
The dried seeds are sorted using the flotation method. Lighter kernels (which are generally
unsound) float to the surface of a tank and can be removed. The sound kernels are sorted based
on their quality and size. Good quality whole kernels are separated from the lower quality and
broken kernels.
For export, the bagged nutmeg is fumigated with methyl bromide.
Grading
Nutmegs are graded according to their size. Sizing can be carried out using different mesh sized
sieves. Larger nutmegs (weighing about 8g) are considered superior and are traded at a higher
price. In Grenada it is usual to specify the size of nutmegs according to the number of dried
nutmegs per British pound. The best nuts are referred to as ‘55’ nuts (8.2g) to ‘65’ nuts (7.0g).
The smallest grades traded are ‘160’ nuts which weigh only 2.8g. Smaller nutmegs and
nutmeg fragments are included in the BWP grade (broken, wormy and punky), which is the
lowest quality.
Packaging and storage
Sorted kernels are bagged and labelled appropriately. They are usually packed into Hessian
sacks or gunny bags. Nutmegs are usually sold whole, either with or without the shell. Ground
nutmeg is also available, but this is generally of inferior quality and can easily be adulterated.
The taste and aroma of ground nutmeg deteriorate very rapidly. Dried whole nutmegs have a long
shelf life if they are stored in a dry place away from sunlight and insect infestation.
Adulterants
There are two nutmeg species that are found as adulterants of true nutmeg or mace: M. argentea
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