Fibre production includes unique challenges and processes. Some of these include:
Retting is the process of separating hemp’s outer bast and core fibres. As a form of controlled biological decomposition, retting is a hands-on process that involves leaving swathed fibre in the field, which is then turned to advance the even decomposition of fibre. Retting weakens the chemical bonds of the fibre allowing decortication. Enzyme based and water retting are two others methods that have been used. Poor retting can impact fibre quality and fibre yield and is a challenge for new growers.
Good quality decortication is a challenging process and research is ongoing into machinery and other methods to reduce the cost of this traditionally mechanical process. Steam explosion, detergents, force methods and ultrasound are other possible methods for decortication. The quality of fibre separation determines what markets can be entered. The principle manufacturers of decortication lines are located in Europe.
Not all fibre is created equal. End users require fibre to meet specific parameters in order to be usable. Examples include fibre length, cleanliness and modulus. There are currently no uniform sector standards, so in practice, fibre standards are developed between processor and end user.
Hemp bales are bulky in volume. As a result of their bulk, transportation distance from field to processor are limited by economics and economically, can only be transported a limited distance from field and factory.
Collection, transport and storage of fibre can greatly affect fibre quality and final yield at plant. Hemp processing plants must also evaluate the land base they are drawing their fibre from.