The trees begin to yield from 7-8 years after planting.
The stage of harvest of flower buds determine the quality of the final dried product.
Buds are harvested when the base of calyx has turned from green to pink in colour.
If allowed to develop beyond this stage, the buds open, petals drop and an inferior quality spice is obtained on drying.
Prior to drying, buds are removed from the stem by holding the cluster in one hand and pressing it against the palm of the other with a slight twisting movement.
Curing
The clove buds and stems are piled separately or drying.
Buds may be sorted to remove over ripe cloves and fallen flowers.
Drying should be done immediately after the buds are separated from the clusters.
If left too long in heaps, they ferment and the dried spice has a whitish shriveled appearance
(khoker clove).
The traditional method of drying is by exposing them to sun in mats.
The green buds are spread out in a thin layer on the drying floor and are raked from time to time to ensure the development of a uniform colour and to prevent mould formation.
In sunny weather, drying is completed in 4-5 days giving a bright coloured dried spice of
attractive appearance.
During drying, clove loses about two-third of its original fresh green weight.
When properly dried, it will turn bright brown and does not bend when pressed.
The dried cloves are sorted to remove mother of cloves and khoker cloves, bagged and stored
in a dry place.
The stem after separation of buds is dried in a similar manner as the spice, without allowing mould formation and fermentation.
Clove bud oil
The essential oil is obtained by steam distillation of comminuted buds or whole cloves.
On distillation, about 17 per cent essential oil is obtained which is a colourless or yellow liquid possessing odour and flavour characteristic of the spice.
Finest oil contains 85-89 per cent eugenol.
Clove bud oil is used for flavouring food and in perfumery.
Clove stem oil
Clove stem oil is obtained from dried peduncles and stem of clove buds (5-7 per cent)
on steam distillation.
The eugenol content of the oil ranges from 90-95 per cent. This oil possesses a coarser and woodier odour than bud oil.
Clove leaf oil
Clove leaves on distillation yield 2-3 per cent oil as a dark brown liquid with a harsh woody
odour.
When rectified, it turns pale yellow and smells sweeter with a eugenol content of 80 to
85 per cent.
Oleoresin
Clove oleoresin may be prepared by cold or hot extraction of crushed spices using organic solvents like acetone giving a recovery of 18-22 per cent.
The oleoresin is chiefly used in perfumery and for flavouring.
