Wet-white provides new market for veg

One of the spin-offs of the growth of wet-white tanning has been the renewed demand for vegetable extracts. Because current technology leaves wet-white hides with an 'empty' feel, they then need to be veg retanned to plump them out. 'Of the veg extracts available, tara is the most suitable for upholstery leather because of its light colouring and because of its greater lightfastness', said Mimosa Central Co-operative Ltd director Dr Neville Slabbert. 'That makes it ideal for all the white, cream, beige and grey upholstery going into the automotive industry.' Tara's downfall is limited supply - in this case, the tannin is concentrated in the fruit pods, which are harvested by small-scale collectors from wild populations in its home range in the Peruvian Andes. The other extracts, quebracho, chestnut and 'mimosa' - the international trading name for what is known locally as wattle - all have their respective strengths and weaknesses. Mimosa's greatest strength is that it is cultivated and supply is not a concern because it is a renewable resource. Its greatest weakness, in this application, is that the extract is relatively dark and lacks lightfastness, making it suitable only for darker colours, especially in the extreme conditions to which automotive leather is subjected. 'Retanning wet-whites with veg isn't a huge market', Slabbert said. 'It doesn't compare with the off-take of a sole leather tannery, for example. How we miss them! 'But, hide for hide, retanning wet-whites with veg requires more extract than retanning wet-blues for, say, shoe uppers. 'Talking of hankering after the past, Silverton Tannery took tons of extract to produce veg tanned upholstery leather for the South African Railways, which was the last railway in the world to have leather upholstery. Perhaps, as with the car industry, leather will make a comeback in railways, too!' Slabbert said Mimosa Central sold more than 20,000 tons of extract into the leather industry annually, but less than 500 tons of that went into upholstery leathers. By comparison, one large sole leather tannery consumes around 1,000 tons annually.