The quills, which may be incompletely dried, may be recleaned, washed in fresh water, thoroughly dried and packed. Good Chinese cassia bark is sweet and aromatic, resembling Ceylon cinnamon in flavour, but is rather less delicate and sometimes slightly astringent; it is less uniformly thin and darker in colour; the outer bark is often less carefully removed, leaving patches of rough, greyish bark.
Cinnamon bark oil is mainly produced by distillation of imported material in Western Europe and North America. A little cinnamon bark oil is distilled in Sri Lanka but this is considered to be a lower-quality product. Cinnamon bark oil is used in both flavouring and perfumery; in the former application, it is incorporated into baked goods, sauces and pickles, confectionery, beverages of the Coca Cola type, and in some dental and pharmaceutical preparations.
The harvested bark is thus of two kinds – rectangular slabs and quills, the latter being obtained mainly from the smaller branches. The unrolled slabs, which are more valuable, undergo complicated traditional methods of curing in different parts of Vietnam. Most of these method involve alternate washing and drying, with minor fermentation in heaps. Finally, the slabs are tied around thick bamboo for drying and so assume a broadly curved appearance. The thinner bark from the smaller branches is prepared as quills by scraping and drying in the usually way.
Cinnamon leaf oil (from C. verwn) is distilled in Sri Lanka, the Seychelles and the Malagasy Republic. The oil is used per se in flavouring and perfumery and, also, as a source of its major constituent, eugenol.
The second class of products are the essential oils obtained by distillation of the leaves of C. verum (cinnamon leaf oil) and from the co-distillation of leaves and twigs of C. cassia (the cassia oil of commerce). A small volume trade also exists in ‘cassia buds’, the dried immature fruits of C. cassia, which are also used as a spice.
The tree can be propagated by cuttings or layers, but these methods are seldom used, although suckers are sometimes transplanted. The tree is usually raised from seed, which should be obtained from selected trees. The fruits are soaked in water, after which the pericarp is rubbed off and the seeds are dried in the shade. They should be planted within a few days, as the seeds quickly lose their viability. The seeds are planted in prepared nurseries, preferably of fine sandy soil, and are shaded and watered. The shade is gradually reduced until the seedlings are about 1 m high at 1 year old, when they are ready for transplanting into their permanent positions. The seedlings should be lifted carefully to avoid damage to the roots and the planting distance varies from 0.9 to 4.5 m, depending upon the soil and other crops. The trees are given an occasional ring-weeding and the lower branches are cut off close to the trunk.