Description / Application
Catechu or cutch, extract from the heartwood of Acacia catechu, a leguminous tree of the pulse family, native to India and Myanmar. Catechu is a fast brown dye used for various shades of brown and olive, including the familiar khaki, and also in tanning. White cutch is a synonym for gambier, a leaf extract of a shrub (Uncaria gambir) of the madder family, which is similarly used. Catechu is an extract of any of several species of Acacia—but especially Acacia catechu—produced by boiling the wood in water and evaporating the resulting brew.
Catechu extract is an astringent and has been used since ancient times in Ayurvedic medicine as well as in breath-freshening spice mixtures, for example in France and Italy it is used in some licorice pastilles. It is also an important ingredient in South Asian Paan mixtures, as well as ready-made Paan Masala and Gutka.
The mixture is high in natural vegetable tannins (which accounts for its astringent effect), and may be used for the tanning of animal hides.
Under the name cutch, catechu is a brown dye used for tanning and dyeing and for preserving fishing nets and sails. Cutch will dye wool, silk, and cotton a yellowish-brown. Cutch gives gray-browns with an iron mordant and olive-browns with a copper mordant.
White cutch, also known as gambier, gambeer, or gambir, has the same uses.
Black Catechu has recently also been utilized by Blavod Drinks Ltd. to dye their vodka black.
Shipment / Storage / Risk factors
Catechi is an extract from the plant Acacia Catechu used medically, in textile dyeing and the tanning industry. Usually packed in wooden cases or bags. Will melt at temperatures of approx. 32°C and harden in cooler temperatures. Liable to absorb moisture, also to lose weight and suffer loss through drainage. There may be loss in weight of cases, due to the use of damp timber. If the liquor of extraction is allowed to cool before concentration, crystallization will occur and the crystallized solid can be separated from the liquor by filtration. This solid is known as ‘Catechin’ or ‘Katha’ and the filtrate which is then usually concentrated to a solid is known as ‘Cutch’.
A tannin having a blackish-brown crystalline appearance. Is brittle and susceptible to heat and moisture, heat causing the clutch to soften. Dissolves in water and moisture will cause staining of boxes or bags. Should not be stacked more than ten bags high or over-stowed by heavy goods. Bags of cutch unevenly stacked are liable to break. Melts easily, in which condition it becomes blocked. This may be regarded as a natural incident of transit.
Usually marketed in tablet form. The outside of a cake varies in colour from light grey to a very dark brown and the appearance of the fracture is that of coloured chalk or clay. Damage to the case should not cause damage to the products inside except through loss, and provided the gunny remains intact there should be little loss. These products should not be exposed to wet as they are hygroscopic substances and, in the case of Katha particularly, if allowed to become damp, will get mouldy.