Coir is a short, coarse fibre extracted from the shell of coconuts. Copra, milk and desiccated coconut are food products made from coconut, and coir fibre is a byproduct of this. 60% of coir comes from India, in particular Kerala, and one third from Sri Lanka.

The two types of fibre are white, extracted from unripe coconuts with thick walls made of cellulose, and brown from mature and ripe coconuts that are more lignin. While the white fibre is soft and fine, the brown mature fibre is very tough and salt water-resistant, with relatively high lignin content (>40%).

It makes up a large proportion of the seed, from the white edible flesh to the hard woody husk. The tradition process of extraction is labour intensive and time consuming – the husks are soaked in water for 12 months (retted), during which time anaerobic fermentation takes place, softening the fibres and allowing them to be separated. The fibres are hammered with mallets to release the individual strands, and then dried in the sun. Industrial manufacturing is much faster, using decorticating machines to extract the fibres after soaking for only 5 days or so.