A Maritime Industrial Hemp Product Marketing Study
Farming and Processing Technology
by Gero Leson and Petra Pless
Environmental Consulting, Berkeley, CA
(in Commercial Hemp, Summer 1998, Vol. 2, Issue 6)
The 1998 hemp crop will depend on the selected varieties and whether or not the weather gods will smile sunnily, but not too dryly, upon the crop. Come mid August for stalks and late September for grain, there will be about 1,000-1,500 tonnes of grain and 12,000-16,000 tonnes of dry stalks waiting to be harvested. How will they get off the field? For grain, most groups will harvest with combines, modified to avoid tangling up moving parts by the easy-wrap bast fiber surrounding the stalks. For fibre only harvests, the HempFlax type harvester with row independent teeth and a subsequent chopper will chew its way through many a field; other options include mower/conditioners and swathers. All of these systems have been shown to work on hemp crops, however, not always without problems. Still lacking is an efficient single-pass harvester, removing and threshing the seeds while also grabbing and cutting the stalks, preferably chopping and dropping them off in windrows in the field. Various concepts are considered in Europe and Canada. Since it will be indispensable for saving on time and labour while preserving stalks, particularly on larger plots, its development in the near future is crucial.
Equipment for turning the stalks during field retting and for baling is available. Again, the wrap-risk will require modification and heightened operator attention. Large bales, square or round, are the way to go for storage and transportation. Manufacturers such as Case IH have had their customers complain about problems, e.g., with the pick-up on square balers and are working on modifications.
The relevant processing routes for Canada and Western Europe, both in existence and conceivable are shown in the Figure E.1. Let’s start with the easier route.
The art of cleaning, drying and storing of seeds-sorry, grain-isn’t exactly new to Canadian farmers. The biggest challenges in grain handling may actually be brought about by Health Canada’s regulations, intended to keep “grain” from becoming “seed”. Yet, there are also technical reasons for caution when handling hemp grain: Not properly cleaned and dried grain attracts mold. f pumped through ducts too fast, the delicate hulls may crack open and expose the meat with its high content of polyunsaturated fatty acids to oxygen and subsequent rancidification. If dried at too high temperatures for too long, oil will ooze out, again contributing to rancidity. Especially groups that grow crops for grain only need to pay special attention to these quality control challenges since they will affect the marketability of their sole product.
Extraction of oil and dehulling are the two relevant processing options for hemp grain. Both of them are available in Canada and have potential for further development. Cold pressing with expeller presses has, in recent years, “become hot” for other oil crops: safflower, canola, flax. A number of pressing facilities are at hand in Canada. Their generally smaller sizes are more suited to the crushing of low-volume crops, such as hemp. Because of the sensitivity of hemp seeds and oil, the main growers in Canada will crush under a nitrogen atmosphere. Such protection from oxygen, and from light and heat is crucial for producing a tasty oil with an acceptable shelf-life.
In addition to completely mechanical cold pressing, several innovative solvent based extraction alternatives are emerging. Solvent extraction achieves considerably higher yields than cold pressing, thus reducing the cost of the oil. While commodity oils are extracted with hexane, a petroleum constituent, innovative extraction processes using “supercritical” liquid carbon dioxide or ethanol provide several advantages. The solvents are less environmentally critical and may enrich the oil with desirable components, such as fragrances or Vitamin E. Potential solvent residues in the oil pose no risks to the consumer. As demand for hemp oil increases, the growing “natural oil” industry will increasingly use these solvent extraction technologies. In addition to the pressing step, there are also capacities for refining and deodorizing smaller quantities of hemp oil to meet the demand by cosmetics manufacturers.
The basic scenarios for grain processing in Canada are exemplified by Kenex Ltd. and R&D Hemp. Jean Laprise of Kenex expects to have their own oil press operational by late summer, while R&D Hemp has contracted for the crushing of their seeds in the prairies.
Dehulling, the removal of the crunchy skin from hemp grain, is also rapidly becoming a hit with hemp seed lovers. The hemp “nuts” are small compared to the established TV-varieties, such as cashew, peanuts and hazelnuts. Yet people begin to discover that they can add a delicate flavor, texture, and even health benefits to baked food and snacks. As with crushing, the hulling of seeds isn’t new in Canada. Yet, modifications to existing equipment may be required to get the tiny nuts sufficiently clean of hull residues without crushing them too much. That this problem can be solved is demonstrated by the nuts produced by R&D Hemp.
Thus technologies for the processing of grain are established in Canada and available in time to process this year’s crop. Higher costs of seeds and low economics of scale still render hemp grain products a great deal more expensive than those from commodity grain. Yet they fit right into the growing higher-price market for other, more wholesome, healthy, and “sustainable” foods and cosmetics.
This is a somewhat trickier story. The decades long absence of a significant fibre crop industry in Canada has left growers and processors with little processing equipment to experiment with. Yet the need to develop modern equipment for fibre hemp has stimulated creativity in both Western Europe and Canada. The purpose of the “mechanical” or “primary’ processing of hemp stalks is the separation of hurds (woody core) from the object of desire, the bast fibre. This is usually done by a sequence of rollers/breakers. Alternatively, the French firm La Chanvrière de l’Aube uses a hammermill. The bast fibre is then cleaned and carded to the desired hurd content and fineness, possibly cut to size and baled. In Europe, where hurds have turned out to no longer be a waste but rather a needed “profit center” their collection, removal of dust, baling and packaging has also become an essential part of modern hemp fibre processing.
Complete processing lines for fibre hemp are available from two European flax equipment manufacturers, the Belgian-German group Charle-Temafa and the French firm Laroche. Since their throughput of dry stalks is generally limited to 2-3 tonnes/hour, the Dutch firm HempFlax has developed and built its own fibre processing line with a throughput of about 8 tonnes/hour. Individual components of flax fibre lines which can be modified to process hemp are also offered by several European equipment manufacturers. Some European processors, such as the German firm BaFa, have developed components, e.g., a bale opener, in-house.
All relevant Canadian fibre-hemp growers have installed fibre processing lines or plan to do so. They will use both imported equipment as well as in-house designs. Kenex Ltd. will employ primarily European equipment. The capacity of their line, which will start-up in August, “exceeds” this year’s crop. Hempline Inc. have developed their own proprietary “hempline”, intended to produce fine, spinnable fiber for furnishing and carpets. The unit, in operation since early June, can process 2-3 tonnes/hour. CGP recently announced the installation of a processing line in Manitoba for fall, likely to involve mostly European equipment.
Usually, the clean and carded bast fibre requires “advanced” or “secondary” processing. Options, which are in various stages of implementation in Canada include:
- Matting, the production of non-woven mats and fleeces for composites, geotextiles, and insulation mats. The requisite technology is established and has, particularly in Europe, been adapted to bast fibres.
- Pulping, the breakdown of the fibre bundles by chemical and physical means to produce elementary fibres for paper making.
- Steam explosion (STEX) or other forms of “chemical retting” which produce a spinnable fiber by carefully removing some of the “natural binders’ present in bast fibre.
Kenex Ltd. is now completing the installation of a matting facility and evaluates the feasibility of a pulping project. Other small-scale pulping plants are operative in North America, including Crane & Co. in Dalton, MA. Still missing, however, is the full-scale implementation of a modern “cottonization” process for the controlled production of finer fibre which can be spun on cotton equipment, thus considerably expanding the use of hemp for apparel. Several European groups are considering a STEX project as the preferred option while CGP is considering such a project for Canada.
Canada is prepared for the processing of the grain and much of the stalks from its first commercial hemp crop. A more decentralized fibre production will require future installation of additional mechanical processing plants and advanced chemical/physical technologies for spinnable fibre. More cost-effective pulping will also be needed.