Tobacco treatment. Part 3
Air-curing process is usually lasts from 5 to 10 weeks, depending on climatic conditions.
Another method of air-curing, is so called, Flure-curing was invented in USA. It is used mainly for pipe and cigar tobacco drying that must be especially bright, for example, Virginia tobaccos. Here the matter consists in the pipe that is lying across entire drying chamber and through which heat is blowing. The advantage of this method consists in that except getting specially light tobaccos, it also takes much less time. Entire process takes 4-5 days.
From other drying methods it worth to name sun-curing, sun drying. But on the Earth there are no so many places where climate allows to dry tobacco on open air. That is why prefer to use combined method from sun-curing and air-curing.
Chemical processes that take place in tobacco during drying process, continue during fermentation. As result of fermentation starch turns into sugar, content of nicotine lowers, proteins disintegrate as well for more small substances. Namely on this stage raw materials transform in tobacco that we know.
Dried tobacco is bind in small wisps which then are laid in big sheaves - per 4-5 tones. Shortly tobacco starts to accumulate temperature. To control it, during the laying in sheaves, from the middle and till the edge are inserted hollow bamboo sticks, in which, in turn, are inserted thermometers. Non-compliance with temperature conditions can lead to situation when aromatic oils that influence tobacco taste can burn out. When, in 4-5 days, temperature in the middle of the sheaf reaches 55-60 centigrade degree, sheaf is separated and tobacco is quickly cooled down after what it is again laid in the sheaves but in such way that tobacco that was previously in the middle would be closer to the margins and vice-versa. Temperature in sheaves starts to grow again but a little slower. When it reaches 60 centigrade degree, tobacco is again moved and it is continued till the temperature doesn't stop to grow. Usually, for this are enough 5-6 laying.
After this tobacco is ready for packing in so called Serones, briquettes that weigh 60 kg that are transported to plants.