poles are called tiers. Barns are built 3 to 4 tiers 

 high. The first tier of poles is at least 9 feet (2.7 

 meters) from the ground, so that the tobacco on 

 the bottom tier clears the ground by at least 3 feet 

 (0.9 meters). The other tiers are 4 or 5 feet apart 

 (1.2 to 1.5 meters). The tier poles are usually 

 about 16 feet (5 meters) long, and strong enough 

 to carry 800 pounds (362.68 kilograms). 



Air-curing operation— Most air-cured tobaccos 

 are harvested by stalk-cutting. Shade-grown 

 wrapper and Puerto Rican filler are harvested by 

 priming. The nutrients that the plant accumulates 

 before harvesting help it to live several days after 

 being cut. When they are exhausted, the leaf dies 

 and is then nearly cured. Air-curing tobacco forc- 

 es the leaves to go through a process of gradual 

 starvation under proper conditions. 



The time required for completely curing stalk- 

 cut tobacco varies, depending on weather 

 conditions, from 5 to 8 weeks for the cigar types, 

 and from 4 to 6 weeks for burley, Maryland, and 

 the dark air-cured types. 



Although the stalks may still be quite green, the 

 cure is finished when the midrib (central vein of 

 the leaf) is dried out and free of sap. The amount 

 of supplementary heat required during the curing 

 period varies considerably with the weather, and 

 is particularly important under cold or exces- 

 sively wet conditions. 



Supplementary heat is almost always used in 

 curing shade tobacco, essentially to protect the 

 product, and to maintain the temperature at a 

 favorable level rather than to elevate it. A small 

 amount of cigar wrapper is cured under high heat 

 to produce a leaf of greenish color. This is known 

 as fire-cured or candela-cured leaf. 



Flue-curing (flue-cured types) 



Type of barn— Two types of barns are used for 

 curing flue-cured tobacco, the conventional 

 barns and the more recently developed bulk 

 curers. The conventional barns are usually 

 square with inside measurements 16, 20, or 24 

 feet (4.8, 6.1 , or 7.2 meters), and contain tier poles 

 spaced about 4 feet (1 .2 meters) horizontally and 

 26 inches (660.4 millimeters) vertically. The barns 

 have solid walls with ventilation provided at the 

 top and bottom. 



Originally, flue-curing barns were heated with 

 wood-fired furnaces of stone or brick built partly 

 outside the barn at ground level. Metal flues from 

 the furnace extended around the floor of the barn 

 radiating heat for curing the tobacco and to carry 

 the smoke and combustion odors outside the 

 barn. The next development was oil-fired furnaces 

 to replace wood. Most conventional barns now 

 use oil-burning heaters or open-flame gas heaters 

 located inside the barn. 



Stalk-cut tobacco hangs in a curing barn. 



Sides of a typical air-curing barn can be opened at various points to adjust air circulation. 

 10 



