Tobacco is a blooming plant that belongs to the nightshade family. It is the most largely harvested non-food crop and is preferred by farmers from more than 120 countries all over the world as it grows under extensively different climatic and soil factors in order to match the requirements of numerous diverse markets.
Generally the tobacco plant grows from 1 to 3 meters in height and delivers 10 to 20 leaves from its stalk. 90% of the world’s tobacco crop grows between 40º north and 40º south, even though} it can be cultivated at up to 60º north.
A native crop of the Americas, tobacco is grown especially for its leaves. Nevertheless, for industrial increase the flowers are chopped off in order to help the leaves to grow further to the stem. Distinctions in soil and climate provide leaves that have particular features and need diverse techniques of fertilization, disease control, harvesting and curing. All of the tobacco types belong to the Nicotiana genus, even though the main base of industrial tobacco is Nicotiana Tabacum. Nicotiana Rustica is also cultivated, although to a reduced extent, and widely used in Oriental tobaccos.
Farmers have elaborated an extensive variety of morphologically diverse types, including the small-leaved aromatic tobaccos, the large and even the broad-leaved cigar tobaccos. Nevertheless, each sort of tobacco is usually described by the treating approach applied to it.
Curing is the ultimate stage in the tobacco manufacturing. Afterwards, the leaves are sold to be converted into the ultimate tobacco product, namely cigarettes, cigars, small cigars or chewing tobacco. By means of curing, the moisture in the tobacco leaf is decreased from 80% to around 20%, thus guaranteeing the tobacco’s preservability. In addition, the diverse techniques of curing also boost the leaf’s pure aroma. As diverse smoking products need leaves with distinct features, the unique flavor of each sort of tobacco is what establishes its appropriateness for use in distinct smoking products.
In curing barns leaves are dried out for a significant period of time. Right after the curing process is finished and the leaf has dried out completely, fresh air is introduced into the curing barn, considerably moistening the leaves as to permit them to be moved for sale without falling apart.
At present there are four curing techniques used for curing tobacco cultivated for commercial reasons: Flue-curing, fire-curing, air-curing and sun-curing