Smoking a cigar, twisted from green leaves, is only harm and no pleasure: first of all tobacco must be freed from various substances that become toxic when burned to make it suitable, or "friendly" for the smoker. In Spanish the process of drying tobacco leaves is called curado, and in English - curing, i.e., "treatment". Very serious chemical changes occur in the composition of the tobacco leaf during the time of this process.
The leaves after collection from the plantation are tied into bunches and hung from the posts in special drying houses. Due to the absence of direct sunlight the process of photosynthesis stops and nutrients are no longer produced. Furthermore, the leaves are deprived of a source of moisture. Under such conditions the tobacco leaf begins to destroy its own reserves of nutrients, including the complex chemical compounds: proteins, starch, carbohydrates, and chlorophyll.
In the process of hydrolysis and oxidation (the reaction of oxygen with the chemical substances in the formation of oxides) the complex chemical compounds are split into simpler components that are less irritating to the smoker. Carbohydrates become polysaccharides, then monosaccharides. Proteins are split into amino acids, ammonia, water, and so on. Carotene appears in proportion to the destruction of chlorophyll in tobacco leaves, which is more pleasant to the taste, and also changes their color from green to brown.
There are four types of drying: sun drying, air-drying, above a fire, and kiln drying at a high temperature. The last method is the most quick: it takes only two - four days. Though, in this case the tobacco loses practically all its aroma, and it is thus necessary to artificially aromatize it. This method is only used with mass-produced cigarettes. Pipe tobaccos are dried by more merciful methods: under the sun or above a fire. In the second case the tobacco acquires a specific "smoky" aroma from the smoke.
The most favorable method of drying for retaining the gustatory and aromatic characteristics of tobacco - and by far the longest - is air-drying in special drying houses. It takes from 40 - 60 days.
A drying house - la casa del tabaco [tobacco house] - is a long building, stretching from east to west where specific climatic conditions are sustained. The optimum temperature is 28-29 degrees Celsius, and relative humidity - 75-85 percent (absolute humidity of 16-26 percent). Enormous doors and a large number of windows make it possible to correct airflow through the structure. The fact is that northern winds, dry and cold, decrease humidity, and southern winds, warm and damp, blowing from the sea, increase humidity. With too low humidity the leaves become fragile, and with too high humidity they begin to spoil.
The main thing is to observe the balance of temperature, humidity, and drying time. For example, too long a drying time can lead to a loss of taste. Much depends also on the conditions the plants grew in. In dry weather the leaves become oily and they have to dry longer. The most reliable index of complete drying is when the central vein of the tobacco leaf begins to burst.