Curing of Tobacco
Meaning of Curing:
1. Removal of moisture from tobacco leaves without affecting its aroma, colour and texture is called curing in tobacco.
2. There are four methods of tobacco curing.
a) Sun Curing:
1. Sun curing the most common method of tobacco curing followed in India.
2. This method is followed for curing bidi, chewing, hookah, snuff and low grade cigarette tobacco.
3. In this method first lower leaves are picked and dried in sun.
4. Later on whole plants are cut and left upside down to dry in field for 3 to 7 days.
5. The leaf portion is stripped off from the midrib known as ‘motiphul’ in Nipani area.
6. The midribs, veins and lamina are collected separately.
b) Rack Curing:
1. Rack curing is followed in cigar, bidi, chutta, chewing and snuff tobacco.
2. The plant are harvested close to ground and kept in the field for initial drying.
3. The plants are brought to yard and hanged on bamboo racks to dry for 4 to 6 weeks.
4. Then they are taken out from racks and piled one over the other on the ground.
5. After two days the plants are rearranged so that those are the top go to bottom and lower plants go to top.
6. This process pilling is done for four times.
7. If heat is generated in the heap during the process of curing some water is sprinkling over it.
8. Then leafy portions is separated from the stem and tied in bunches.
9. The bunches are heaped in a corner of room.
10. The heap is turned over every two days till leaves dried completely and no heat is generated.
c) Flue Curing:
1. Flue curing is followed in the production of high grade cigarette type tobacco.
2. Tobacco is cured under artificial heat in flue curing barns.
3. The leaves are tied in a log of three by their stalks and hanged on the bamboos in the barn.
4. When the barn is loaded, it is closed and fire is set in the oven.
5. The curing process is completed in three stages –
a) Yellowing of Leaves:
i) The temperature of the barn raised upto 310C for three hours.
ii) Then temperature is quickly raised to 520C and held for 30 min.
iii) Then temperature is again reduced to 310C by drawing of the fire and opening the ventilators.
iv) During this stage leaves give off moisture and becomes yellow in colour.
b) Fixing of Colour:
i) The temperature of barn is raised slowly to 490C and air is allowed freely.
ii) The leaves are kept at this temperature for 30 hours.
iii) The colour of leaves get fixed and they cured.
c) Drying of Leaves:
i) The temperature of barn is raised again to 600C to 770C for 20 hours
ii) The midribs and leaf stalks get dry and curing is completed
iii) The moisture content of cured leaves should be between 8 to 18%.
Pit Curing:
1. Pit curing is old and crude method of tobacco curing and is followed only for chewing and hookah tobacco.
2. The farmer is interested in taste and aroma of tobacco and not in burning quality.
3. The curing is done in pits of 90 x 90 x 90 cm sizes.
4. The pits are tied all around with jawar kadbi or straw.
5. The tobacco plants are kept in layers in the pit and top layer is covered by straw and gunny cloth.
6. The top is covered by soil well above ground level so, water will not seep into it.
7. The leaves are kept for one to two weeks.
8. If pit is over heated some water is sprinkled over it to cool down the temperature of pit.
9. The leaves are then taken out and twisted into ropes or made into bundles.