PEPPERMINT. 



25 



from drying, his experiments along this line showing that the dry 

 plants can be distilled three times as rapidly as the green plants, and 

 that a larger quantity of oil may be obtained. He states that — 



To obtain the best results, both as to quality of essential oil and economy of 

 transportation and distillation, the plants should be dried as thoroughly as pos- 

 sible without endangering the loss of the leaves in handling. Distillation 

 should then take place as soon as convenient to prevent the oxidation of the oil 

 in the leaf by atmospheric action. 



The smaller producers, who have no stills of their own, have their 

 mint crop hauled to the nearest peppermint distillery, where it is 

 distilled for them at a cost of 25 cents per pound of oil. 



DESCRIPTION OF STILL. 



The apparatus used in peppermint distillation in the early years 

 of the industry in this country consisted of a copper kettle, from 

 the top of which a pipe connected with a condensing "worm." 

 Water was placed in the kettle and the plants were immersed in it, 

 and direct heat was applied to the bottom from a furnace. With 

 such a still only about 15 pounds of oil could be obtained from a 

 charge. In 18-16, large wooden vats were substituted for the copper 

 kettles, and the plants were distilled by steam passing through them. 

 The kettle formerly used as the still was now employed to generate 

 steam, a long pipe conveying the steam to the bottom of the vats. 

 With this method of distillation from 75 to 100 pounds of oil could 

 be obtained from a charge without much additional .expense. 



A modern peppermint still (fig. 3) may be briefly described as fol- 

 lows: The apparatus required consists of a boiler, a pair of large 

 circular Avooden vats, a condenser, and a receiver. The boiler, of 

 course, is used for the generation of steam. 



Two wooden vats are used in order that they may be filled and 

 emptied alternately. These vats are about G feet high and about 

 5 feet in diameter, with tight -fitting removable covers and perfo- 

 rated false bottoms. Steam pipes are led from the boiler into the 

 bottom of the vats. 



The condenser consists of a series of pipes of block tin, either 

 immersed in tanks of cold water or over which cold water is kept 

 running, the condenser being connected with the top of the dis- 

 tilling vats. The condensed steam, together with the oil, flows into 

 a metallic receiver, in which the oil, being lighter than the water, 

 rises to the top and can be drawn ofl". 



The perforated false bottoms with which the vats are supplied 

 permit the passage of steam. A strong iron hoop is placed about 

 this false bottom, and two pairs of stout chains, which meet at the top 



