Retting
Dew retting, (a microbial decay of pectin, the substance that glues the outer fibre to the inner woody core) in the field is possibly the most commonly used traditional method of separating the outer stalk fibres from the inner woody core (hurd). This is weather dependant and should be completed with several machine turnings of the stalks (similar to hay) within 12 to 18 days.
Other methods used in the past, such as pond retting or stream retting, which use moisture and bacteria to complete the process are less practical or not possible in modern times. There are many other methods of decorticating now being developed, such as steam explosion and ultrasound, so this is an area of the industry still open for more research and development and hopefully some good Kiwi ingenuity.
Possibly, machines such as the transportable Hill Agriculture decorticator are more attractive, as the other methods require transport of the crop as it is cut and are therefore very bulky.
Hemp needs to be processed close to the growing area
Due to the bulky nature of the raw material & its number of components with quite different applications, this is an indisputable fact. In the view of the NZHIA it is a positive aspect however, as it will by necessity, reverse corporate centralisation of production which could easily revitalise ailing rural communities.
The needed Research & Development dollars are only just starting to be spent in this area with some promising results, portable decorticators which are able to separate out the various components that make up the useful parts of Industrial Hemp. Whole Hemp pulping technology has been developed, and plants are being setup in Canada & Victoria, Australia with the assistance of the Ukrainians, who developed the process.
Primary processing
This form of processing close to the growing area, would, in the case of a fibre crop – involve splitting the dried (and retted) hemp stalks into their 3 main parts which include 2 types (lengths) of Bast fibres from the inner and outer layers of the stalk, plus the hurd from the woody inner portion of the stem. Crops allowed to fully develop would also under the right circumstances yield another marketable commodity, the seed.
As Hemp has not been cultivated by western cultures on any real scale for the last 80 years, there are many areas of its production which need to be developed. There is a demand for suitable machinery to harvest fibre and seed crops, to ret and decorticate the stalks and to process them into higher value added products.
Local output from the processing phase will range from providing marketable commodities suitable as raw materials for other industries, through to maximum added value, when hemp based, finished goods are produced and sold.
With minor changes to existing production technology, some products can already be produced; others will require research and development to provide the expertise and knowledge needed to satisfy their production cycles at a cost effective scale.