Cutch and Katha are obtained by boiling in water, chips of heartwood of Acacia catechu (khair) as the chief constituent of heartwood are Catechin (katha) and catechu-tannic acid (cutch). The manufacturing process is essentially extraction rather than distillation as the chips are boiled in water and not treated with stream.
The manufacture of Cutch and Katha is done by Country method as well as by Factory method. But the country method is wasteful. In Factory Method, wood is chipped by disintegrators and boiled chipped in copper vessels with hot water under slight pressure. The extract is concentrated in vacuum and cooled in a refrigerator tank for about a week, when Katha crystallizes out. It is separated by filter presses cut into slabs and further sliced into square tablets which are then dried. The yield of Katha by this method is about 4 to 5 % by weight of the wood. To obtain Cutch, the liquor is further concentrated in evaporators to a consistency at which it is solidified on cooling. The Cutch yield is about 10 to 12% by weight of the wood.
Katha is mainly used in Pan but sometimes also used in medicine. Cutch is an important commercial product which is used as dyeing and preservative agent. It is used in dyeing cotton and silk and in calico-printing.
