Aromatic Plants> Citronella

Distillation :

The grass is steam-distilled for better recovery of oil and economical purposes. The distillation equipment consists of a boiler in which steam is produced, a distillation tub for distilling the grass, a condensor and 2-3 receivers /separators. The distillation tub is made steel with a perforated bottom, which of mint called false bottom, on which the grass rests. It has two opening: one at the bottom for steam entry and the other at the top through which the oil vapour and steam escape. The top of the still is fitted with a lid, which is removable. Charging and discharging of the grass is done in perforated cages with chains. These cages may be lowered in the tub with the help of chain-pulley system. Tubular condensers oil vapours, coming out from the distillation tub, enter from the top of the condenser and cool down while passing through the tubular tubes. Oil and water vapour after condensation are led to a receiver where the oil separates out from the water and floats on the top and is drawn off.

The harvested grass sometimes contains dead leaves. These should be removed. The remaining leaves are cut into shorter lengths. This reduces the volume of the grass and facilities firm and even packing within the still. Further, chopping the grass gives a higher yield of oil compared to uncut grass. Generally, distillation is complete within 21/2 to 3 hours under normal pressure starting from the initial condensation of the oil. About 80% of the total oil yield is recovered in the first hour, 19% in the second hour and about 1% in the 3 hour, of distillation. Larger percentages of the major components in the total oil, such as citronellal, geraniol, citronellal and geranyl acetate are recovered on the first hour of distillation.

Growers cultivating smaller areas can make use of properly designed direct-fired stills, in case they are not able to invest in the purchase of a boiler. In such cases, the lower portion of the distillation tub is filled with water and this function as a boiler. The water in the boiler is separated from the remaining part of the still by means of a false perforated bottom on which the grass rests. In the still, the water does not come in contact with the grass. The tub is heated from below either by wood or coal and the steam thus produced passes through grass place above in the tub carrying oil vapours with it. However, distillation in such direct-fire still takes a little more time and the quality of the oil is also inferior.

Java citronella oil should preferably be stored in glass /aluminum containers.