One of the most commonly known attributes about hemp fiber is its exceptional tensile strength which is 3X that of cotton. In addition, the fiber is naturally antimicrobial and resistant to ultraviolet light as well as mold, mildew, heat and insects which makes it excellent for outdoor wear. The fiber is not only many times more durable than cotton but warmer, softer and more water absorbent. This also makes hemp more absorbent to dyes and thus less prone to fading. Because of hemp's superior insulating properties, it keeps you warm in the winter and cool in the summer. Hemp fibers actually soften with each washing without fiber degradation. Hemp production uses significantly less chemicals than cotton which makes it more sustainable and naturally more suitable for people with chemical sensitivities. The fiber is completely biodegradable, holds its shape as good as polyester but also has breathability. The fibers, which are naturally light in color, require little or no bleach.
Fiber to fabric:
While it is legal in the US to own hemp products such as clothing and foods derived from the plant, it is illegal to cultivate it here. This makes the US the only industrialized nation on earth that does not allow its production based on a law that does not make the distinction between industrial hemp from marijuana. All hemp fabric is therefore imported. The primary countries supplying hemp to the US include China, Hungary, Thailand, Romania and Chile with production coming from other nations including Australia, England, Canada and New Zealand as well.
The basic process of creating hemp fabric for garments is four fold:
Centuries old traditional eco-friendly methods of mechanical hemp processing are still used in countries such as Romania and Hungary. Modern methods include chemical rather than mechanical processes which are faster, less labor intensive and ultimately less expensive. Unfortunately, there are manufacturers out there who are more interested in profits and as a result opt for the chemical methods as opposed to protecting the health of the consumer and our environment.
The process of separating the bast fibers from the stalk is called "retting". The organic methods of separation are both natural and mechanical. The retting process breaks down pectin and lignin, the substances that glue the fibers to the stem core. Two natural retting techniques are dew and water retting. Both methods use a bacterial action to break down the glue, the former aided by dew or rain where as the later takes the bundled hemp and floats it in water to loosen the fiber from the stem.In dew retting, stalks are first cut in to 12-18" lengths and are then left in the moist fields. In order for the stalks to dry, they are then racked together every few days followed by bailing when drying and retting is complete. The dew retting process takes approx. 2-3 weeks to finish based on weather conditions. In water retting, the stalks are soaked for approx. 20 days to loosen the fiber. This method produces a higher quality fiber but is costly and if the water is not disposed of properly can pollute the body of water used in the process. In both methods, the stems must also be monitored to avoid excessive degradation.
A seemingly primitive labor intensive mechanical process is called scutching Once the stems are removed and washed, they are beaten to remove the soft tissue. This is followed by drying so that only the fibers remain. More modern mechanical methods use steam and specially designed machinery on site to separate the fiber from the hurd (the pulp by-product after fiber is removed). In eastern Europe the primary means of processing rely on traditional organic methods including new cleaner biologically-based enzyme technology. In contrast, China, the worlds leading producer of hemp fabric uses chemical methods of processing.
Spinning hemp fiber in to yarn which is then weaved or knitted into garments is essentially the same for hemp processed by chemical or organic means. The only real difference between the two is the fiber length. Organic fibers are generally longer whereas chemically processed hemp becomes "cottonized" and tends to have short fiber. The spinning equipment may vary as a result but the process remains same.
Organic cleaning and softening methods and machinery are currently being researched and developed by ecologically-minded hemp textile manufacturers. This enables the fabric to remain organic and chemical free as well as retain its softness and durability, a characteristic that is often diminished using chemical means. The natural light color of hemp fiber prevents the need to use toxic chlorine bleach. If lightening is absolutely necessary, an eco-friendly non-toxic alternative is hydrogen peroxide.