Tob. Sci., 1960, 4-12, p. 49-55, ISSN.0082-4523

Bulk curing of bright leaf tobacco

Agricultural Engineering Department, North Carolina State College, Raleigh, North Carolina USA; Farm Electrification Research Branch, AERD, ARS, United States Department of Agriculture, Agricultural Engineering Department, North Carolina State College USA

This paper describes the research and development of a curing operation which is more compatible with mechanization of bright-leaf tobacco than conventional curing. The feasibility of bulk curing was well established by laboratory studies during 1955-1957. During 1958 an applied study in bulk curing of intact leaf was conducted in which laboratory techniques and findings were extended to encompass a pilot operation, intermediate between laboratory and field operations. The curing system was designed for simplicity of loading and unloading racks of bulked tobacco, regulation of air flow and temperature schedules which enhance the quality of the cured product, and maximum operational efficiency. Results of curing in the pilot operation show a possibility for acceptance of bulk-cured tobacco by the tobacco industry. Chemical results showed no significant differences between bulk (intact) and conventionally cured tobacco. Smoking tests rated bulk-cured tobacco as suitable for cigarettes. Representative samples of the bulk-cured leaf averaged $62 per cwt on the open market, with a high of $70 per cwt. Possibilities for achieving advantages over the conventional curing method are discussed. The described engineering advancements in bulk curing are presently well adapted for conventional harvesting, but there is also the important possibility of integrating mechanical harvesting with bulk curing. Since many requirements for leaf selectivity and orientation in the barning operations are eliminated by bulk curing, this method offers simplifications in the total mechanization of the harvesting and curing operations.