Tobacco leaves, an annual or Limited perennial herb, Solanaceae. This plant is covered with glandular hairs and the stem is 0.7-2meters high. Petiole inconspicuous or winged. Panicles terminal. Calyx tubular or tubular campanulate, corolla funnel-shaped, end partis pink.

Capsule, seed orbicular or broadly oblong, yellowish brown. It is native to South America and cultivated all over the world. Tobacco leaf is the raw material of tobacco industry.

Phnix Tobacco leaf drying process

Tobacco leaf drying is a constant process, to make the process more convenient, and tobacco drying process can be devided into 3 steps or periods among the whole drying process, accroding to the tobacco leaf change differences during the drying process, and different drying requirements during tobacco changes.

1. Yellowing period

Lower temperature, higher humidity, less ventilation and longer time should be adopted. The main yellowing temperature of tobacco leaves should be controlled at 35-38℃, and the temperature difference between dry and wet bulb should be kept at 2-3 ℃, so that the leaves can reach 70%-80% yellow and become soft. The yellowing temperature should be controlled below 40-42℃, the wet bulb temperature should be kept at 35-37℃, to make the tobacco leaves almost become yellow, fully withered and collapsed, and the main vein should be soft, so as to ensure the full transformation of tobacco leaves and form more basic aroma substances. Therefore, at 41 ~ 42 ℃, the time should be extended properly to make the tobacco leaf reach yellow leaf, green stripe, full wither and collapse, and the main vein become soft.

2. Fixation period

Remove water from leaves and accelerate drying process. Through a large amount of water to remove constraints and ultimately stop the changes in the material in the leaves, the quality has been fixed. In the process of dehydration, the part that hasn't turned yellow has turned yellow, so we should pay special attention to the formation of aroma substances, browning reaction and other important effects on the quality. In order to ensure the drying, full yellowing and the formation of aroma substances, higher temperature, lower humidity, larger ventilation and sufficient time should be taken. In the stage of color fixing, the temperature should be raised at a proper speed according to the quality of tobacco leaves, and the humidity should be controlled to ensure that the tobacco leaves turn to yellow color completely and color fixing smoothly. When the dry bulb temperature is around 46℃-48℃ and the wet bulb temperature is 37℃-38℃, the tobacco gluten turns yellow, when tobacco leaf become small and appears yellow with gluten drum, keeps the wet bulb temperature at 38℃-39℃, the dry bulb temperature at 54℃, and when the tobacco leaf appears big drum, then can be reached by properly stretching for a long time, so as to promote the formation of more aromatic substances.

3、Dry gluten stage

It is mainly the period of removing water from the main vein. The main vein structure is close, the volume is large, the water transfer distance of cells is long, and the vaporization and elimination is slow. However, the temperature should not be too high during the dry gluten period, otherwise, it will cause the volatilization loss or further transformation of the aroma causing substances and reduce the quality. In order to improve the color and chroma of tobacco leaves, and reduce the volatilization of aroma substances, the maximum temperature of dry bulb should be controlled at 65-68°C and wet bulb temperature should be controlled at 40-43°C.