For the past eighty years the oil has been distilled as it is to-day. Concerning the oil distilleries in the Amraoti district, J. H. Burkill1) has issued an interesting report based on his own observations. The oil distilling industry about Ellichpur is worked in the following way. The forest lands where Cymbopogon Martini var. motia grows are leased out to men of substance-generally Mohammedans, who for the most part sub-lease them again piece-meal to men who go out to selected valleys in the Melghat with stills and engaging villagers send some out to cut the grass tops at so much per hundred bundles brought in, and with others set up open-air distilleries on the banks of the streams. There is built first a row of stone fire-places and the cauldrons are set up on them, generally 3 or 4 in a row. The cauldrons are sometimes of iron and sometimes of copper. If they are of copper they are generally somewhat smaller than those of iron and depressed globose; the iron cauldrons are cylindrical and rivetted; they are about 21/2 feet in diameter. The top of the iron cauldrons is slightly conical with a central lid. Out of the lid emerges the bamboo elbowed tube by which the distillate passes off.
The cauldron once set in place ready for the fire, is never moved.
The elbowed tube has a bamboo peg run through it at the angle and is wrapped from end to end in string. From the elbow the longer part is about six feet.
The receivers are generally long necked, more than a foot in diameter below, not so deep as broad (neck excluded). But sometimes they are without a neck, in which case a pad of cloth on the bamboo closes the mouth. They are generally made of copper. They are placed in the water quite up to the neck. A framework of wood lies in the stream which is generally dammed to deepen the water. Into the interspaces of this frame-work the receivers fit, being held in place by means of two sticks of wood which are tied on either side of the neck and are placed under the cross bars of the framework. Further, stones are heaped round each receiver to help to keep them under water.
1) Report of Schimmel & Co., October 1909, 87.
Fig. 19. Copper (above) and iron (below) still for palmarosa oil.
The method of work is as follows. We will suppose that the cauldron has just been emptied of a charge and lies with the lid off and with the fire drawn from below it. A workman standing on the stone walls round the cauldron, with a rod measures the depth of the water in it. This water is brown and holds a considerable amount of tannin derived from previous charges of grass. Next he pours enough clean water into the cauldron to bring the depth up to about (for a large cauldron) 10 - 12 inches and next packs in the grass often trampling it down in order to get as much as possible in.
The stills are of different sizes. The larger one takes a charge of about 200 bundles of grass (each bundle containing about 300 stems) and the smaller takes about half the quantity. Next the lid is replaced and the joint luted up with a paste of flour of udid (Phaseolus) and a muddy bandage. The bamboo tube is inserted into the hole in the lid where it fits and is similarly luted in. Next, fire is put under the cauldron and boiling recommences.
The boiling lasts two or three hours; and according to the arrangements which the masters make with the men, five or six boilings are done in the twenty-four hours.
The bamboo passes into the receiver for a distance of about six inches. After a while the bubbling of the steam through the increasing distillate begins to give what the workmen describe as the sound "tit-tit". The sound deepens and when it becomes what they call "bul-bul" they know to stop the boiling. In doing this the fire is removed, cold water is thrown over the lid of the cauldron, the bamboo tube removed, the lid lifted, and the receiver taken out of the stream. The pressure of the steam in the cauldron is at the time not inconsiderable.
While some men with a hay-fork are removing the exhausted grass from the cauldron, the master takes with a spoon the oil from off the top of the water in the receiver and using a funnel of tin he separates it from any water which the spoon brings up with the oil.
In some stills lime juice is used now to help to clarify the oil.
Three large cauldrons give about a pint and a half of oil, which on standing deposits a sediment of a copper salt.
All the oil of each small distillery is mixed together and carried to the nearest trade centre - Ellichpur, for most of the stills examined.
Table salt to the extent of half a pound is thrown into each cauldron every few days.
Figures 21 and 22 illustrate the distilleries found in the Khandesh1) circuit to the west of Amraoti. It is customary to build a roof over the stills. A large piece of wood is used as top or cover of the still. The method of procedure is the same as that described above. Whereas in Amraoti salt is frequently added to the still, this is done but rarely in Khandesh. In the latter place the period of each distillation is also extended. In Khandesh both palmarosa and gingergrass oils are distilled, the former in the lower regions, the latter on the Akrani plateau. At medium altitudes the available palmarosa grass is distilled first, then the gingergrass.
1) A description of the oil distillation in Khandesh can be found in the book Pharmacographia indica by Dymock, Warden and Hooper, part VI, p. 558; comp. Arch, der Pharm. 234 (1896), 321.
Fig. 22. Palmarosa distillation in Khandesh (Nearer India).