Coconut Fiber (Coir) – an abundant, renewable natural resource
Coir is processed from the husk of the fruit from the coconut tree (Cocos nucifera), which is a tall palm tree native to East India. The coconut fruit is a large oval shaped fruit with a fiber husk and a hard shell that encloses the edible meat and milky fluid. The milky fluid in young coconut fruits is a great tasting and healthy drink. The white edible meat of coconut fruit is a popular ingredient in many dessert and curry recipes. In addition to the edible meat, the entire tree is very famous for multiple uses. Coconut leaves are used as a roofing material in temporary sheds, while the leaf stems are used for fire wood. The trunk of the coconut tree is an elegant interior decorating wood as well as excellent roofing lumber. The hard shell is burned, and the charcoal is used for activated carbon products.
Coir fiber has the highest strength and durability of any readily-available natural fiber and use for making a variety of products including products for protecting and improving natural resources. Coir is the fiber processed from coconut husks that have been cured in water. This abundant natural resource is a by-product of the coconut industry. It is a plantation crop growing mainly in the tropics. Each coconut tree harvested once in every 7 weeks and year-round production of coconuts assures the availability of coconut husks. Traditional coir processing begins with curing (retting) the coconut husks in freshwater for at least three months. This curing the coconut husks in fresh water turns the coir fibers to dark brown in color. It also increases the durability, strength and flexibility of the coir. With skilled processing, coir fiber can be separated into different grades, depending on the length of the fiber. This fiber separation process is done only in Sri Lanka, and the Sri Lanka coir products are superior to coir products made in other countries.
During processing, the initially separated fiber is called mattress coir fiber. These are short and flimsy. The next fiber separated is called omat coir fiber. They are medium in length and thicker than mattress coir fiber. The longer and thicker fiber left after separating the mattress and omat coir fibers are called bristle coir fiber. Bristle coir fiber is the best quality coir fiber in the market and has very slow biodegradability. The left over particles once all the fibers are separated is called the coir pith (dust). Although it has very little nutritive value, the porous coir pith is an excellent soil-less plant growing medium. Coir pith also use in worm and reptile bedding, as well in environmental cleanups.
Coir – fiber obtained from coconut husks
Coir pith/dust – the soil-less potting medium
Recently for convenience, some millers are processing fiber with quick defibering machines. The fiber process from this method is not as flexible or durable as the fiber process from traditional method. India, Philippines and a few other countries cure their coconut husks in lagoons. These fibers are generally white in color due the bleaching effect from salt in lagoon water and they tend to contain excess salts too.
Coir fiber and Jute fiber are completely different fiber types. Coir fiber products are stronger and more durable than Jute fiber products. JuteMats have very low strength and durability and it is in the lower end spectrum of erosion control blankets and the woven bristle coir blankets in the high end.