October, 1912.] 



295 



FLUE CURING TOBACCO. 



In the Flue Curiug-Prccess the open fires are replaced by flues con- 

 veying hot fire. 



This American system has been successfully adopted by Mr, H. W. 

 Taylor, who has installed at the Rustenburg Station in the Transvaal a 

 model curing-house based on this principle and which proves particularly 

 useful in the preparation of the light yellow leaved tobacco. The yellow, 

 ing of the leaves is an improved method which should only be applied 

 where it can be carried out in its entirety with all the care necessary to 

 ensure the production of a tobacco (hat will fetch the high prices in 

 view of which the method has been devised. Thus for its complete success 

 all the special instructions, of which the chief deal with the choice of 

 the variety of tobacco, topping, and the gathering of leaves, must be 

 followed. 



The varieties which in the Transvaal have given the best yellow 

 leaves by the flue curing-process are : Yellow Pryor, Bullion, Hester, 

 Blue Pryor, and Boyd 1269. The tobacco intended to be flue-cured must 

 be cut low, leaving only 12 to 16 leaves having about the same degree of 

 maturity. The harvest is carried out in three times, beginning with the 

 lowest leaves which are the first to ripen. They must be separated from 

 the stem in the field and conveyed to the curing house in large flat 

 baskets. 



The > lue House. 



The curing house must be small, and divided into four chambers able 

 to contain 480 laths bearing the tobacco of 3.360 plants. Each curing 

 house may be refilled three times per month, so that 10,080 plants may be 

 cured in the course of a month. Each chamber in its turn is sub-divided 

 into five floors, of which the lowest is the loftiest to prevent the tobacco 

 in it being injured by too high temperatures. A flue in which hot air 

 circulates runs all round inside the house at about 2 feet from the walls 

 and issues at a level about 3 feet higher than its starting-point at the 

 fire-place situated about 2 feet above the earth. 



The Process. 



In flue-curing there are four stages through which the tobacco passes : 

 the yellowing, fixing the colour, drying the leaf and drying the central 

 rib and stalk. A moderate fire is kept up at first, and gradually increased 

 up to about 89*6° F. ; after 10 hours the temperature is raised to 100 4°F., 

 when the tobacco begins to turn yellow ; the temperature is still further 

 raised toll9'3°F. and kept up till the leaf is completely yellow. The 

 colour is then fixed by heating gradually up to 131° F. and then sinking 

 tol25 , 6°F.. at which temperature the tobacco is kept until the leaf is 

 practically dry. In order to cure completely the leaf and the central rib 

 the temperature is raised in two hours to 131°F. and kept at this for six 

 hours ; by successive btages of six hours each the temperature is raised 

 to 135-5° F., to 143-6° F. and at last to 159-8° F. at which it is kept during 

 8 or 10 hours until the stalk is completely dry. Mr. H. W. Taylor re- 

 commends that fire be extinguished as soon as the operation is ended 

 and the curing house allowed to cool down ; after which the ventilators 



