Uses of Hemp
Hemp is used for a wide variety of purposes, including the manufacture of cordage of varying tensile strength, clothing, and nutritional products. The bast fibers can be used in 100% hemp products, but are commonly blended with fabrics such as linen, cotton or silk, for apparel and furnishings, most commonly a 55/45 Hemp/Cotton blend. The inner two fibers of hemp are more woody, and are more often used in non-woven items and other industrial applications, such as mulch, animal bedding and litter. The oil from the fruits (”seeds”) dries on exposure to air (similar to linseed oil) and is sometimes used in the manufacture of oil-based paints, in creams as a moisturising agent, for cooking, and in plastics. Hemp seeds are often added to wild bird seed mix.
Material
In Europe and China, hemp fibers are increasingly used to strengthen cement, and in other composite materials for many construction and manufacturing applications. Hempcrete is used as a construction material containing hemp hurds, especially in France. Mercedes-Benz uses a “biocomposite” composed principally of hemp fiber for the manufacture of interior panels in some of its automobiles.
Food
Hemp seeds are highly nutritious, and contain beneficial omega fatty acids, amino acids, and minerals. The seeds can be eaten raw, ground into a meal, sprouted, made into “milk” (akin to soy milk), prepared as tea, and used in baking. The fresh leaves can also be eaten in salads. Products range from cereals to frozen waffles, hemp tofu to nut butters. A few companies produce value added hemp seed items that include the seed oils, whole hemp grain (which is sterilized as per international law), hulled hemp seed (the whole seed without the mineral rich outer shell), hemp flour, hemp cake (a by-product of pressing the seed for oil) and hemp protein powder. Hemp is also used in some organic cereals, for non-dairy “milk” somewhat similar to soy and nut milks, and for non-dairy hemp “ice cream.” Given that seeds account for 50% of the weight of a female plant grown for seed, these products can be made cheaper than with soy, almonds, or flax.
Within the UK, the Department for Environment, Food and Rural Affairs (Defra) treats hemp as purely a non-food crop. Seed can and does appear on the UK market as a legal food product although cultivation licenses are not available for this purpose. In North America, hemp seed food products are sold in small volume, typically in health food stores or by mail order.
Nutrition
| Calories/100 g | 503 |
| Protein | 23 |
| Carbohydrate | 35 |
| dietary fiber | 35 |
| Fat | 30 |
| Saturated fat | 700 |
| Palmitic 16:0 | 2 |
| Stearic 18:0 | 1 |
| Monounsaturated fat | 4 |
| Oleic 18:1 (Omega-9) | 4 |
| Polyunsaturated fat | 23 |
| Linoleic 18:2 (Omega-6) | 17 |
| Linolenic 18:3 (Omega-3) | 5 |
| Linolenic 18:3 (Omega-6) | 1 |
| Moisture | 6 |
| Ash | 6 |
| Vitamin A (B-Carotene) | 37 IU |
| Thiamine (Vit B1) | 1 mg |
| Riboflavin (Vit B2) | 1 mg |
| Vitamin B6 | 0 mg |
| Niacin (Vit B3) | 1 mg |
| Vitamin C | 1.0 mg |
| Vitamin D | 10 IU |
| Vitamin E | 3 IU |
| Sodium | 0 mg |
| Calcium | 2 mg |
| Iron | 0 mg |
| Source: [3] |
30–35% of the weight of hempseed is oil containing 80% essential fatty acids (EFAs), linoleic acid (LA, 50-70%), alpha-linolenic acid (ALA, 15–25%) and Gamma-Linolenic acid (GLA, 1–6%). The proportions of linoleic acid and alpha-linolenic acid in hempseed oil meet human requirements for EFAs. Unlike flax oil and others, hempseed oil can be used continuously without developing a deficiency or other imbalance of EFAs. Unfortunately the unsaturated fat makes the oil rancid quickly, unless it is stored in dark coloured bottles or mixed with chemical preservatives. This makes hemp oil difficult to transport or store. The high unsaturated fat content also makes the oil unsuitable for frying. This severely limits hemp oil’s potential on the food market, although some marketing potential exists as a nutritional supplement. Cold-pressed hempseed oil is nutritionally superior to olive or flax oil, and so, makes a great alternative in salads, smoothies, and other non-frying uses. Cooking of any oil reduces its nutritional value, and may convert beneficial fatty acids to less benign substances.
Hemp seed also contains 20% complete and highly-digestible protein, 1/3 as edestin protein and 2/3 as albumins. Its high quality amino acid composition is closer to “complete” sources of proteins (meat, milk, eggs) than all other oil seeds except quinoa and soy.
Medicine
Fiber
The fiber is one of the most valuable parts of the hemp plant. It is commonly called bast, which refers to the fibers that grow on the outside of the woody interior of the plants stalk, and under the most outer part (the bark). Bast fibers give the plants more strength, which is especially true with the hemp plant. Hemp fibers can be 3 feet (0.91 m) to 15 feet (4.6 m) long, running the length of the plant. Depending on the processing used to remove the fiber from the stem, the hemp naturally may be creamy white, brown, gray, black or green.
The use of hemp for fiber production has declined sharply over the last two centuries, but before the industrial revolution, hemp was a popular fiber because it is strong and grows quickly; it produces 250% more fiber than cotton and 600% more fiber than flax when grown on the same land.[citation needed] Hemp has been used to make paper. The Declaration of Independence was drafted by Jefferson on hemp paper.[10] It was used to make canvas, and the word canvas itself derives from cannabis.[11][12] Hemp was very popular as it had many uses. However, as other coarse-fiber plants were more widely grown and lobbying by various industries increased, hemp fiber was replaced in most roles.[citation needed] Manila replaced its use for rope. Burlap, made from jute, took over the sacking market. The paper industry began using wood pulp. The carpet industry switched over to wool, sisal, and jute, then nylon. Netting and webbing applications were taken over by cotton and synthetics. The world hemp paper pulp production was believed to be around 120,000 tons per year in 1991 which was about 0.05 % of the world’s annual pulp production volume.[13]
In 1916, US Department of Agriculture chief scientists Lyster H. Dewe, and Jason L. Merrill created paper made from hemp pulp, which they concluded was “favorable in comparison with those used with pulp wood.”[14] Jack Herer, in the book “The Emperor Wears No Clothes” summarized the findings of Bulletin No. 404.[15]
| “ | In 1916, USDA Bulletin No. 404, reported that one acre of cannabis hemp, in annual rotation over a 20-year period, would produce as much pulp for paper as 4.1 acres of trees being cut down over the same 20-year period. This process would use only 1/4 to 1/7 as much polluting sulfur-based acid chemicals to break down the glue-like lignin that binds the fibers of the pulp, or even none at all using soda ash. The problem of dioxin contamination of rivers is avoided in the hemp paper making process, which does not need to use chlorine bleach (as the wood pulp paper making process requires) but instead safely substitutes hydrogen peroxide in the bleaching process. … If the new (1916) hemp pulp paper process were legal today, it would soon replace about 70% of all wood pulp paper, including computer printout paper, corrugated boxes and paper bags. | ” |
New technology has allowed for more environmentally-friendly paper production from wood pulp The recovery boiler was invented in the early 1930s. The first recovery boilers were commissioned to wood-pulp mills during the mid-1930s[16]. ECF (Elemental Chlorine Free),[17] or TCF (Total chlorine Free) bleaching, better fiber filters etc. has created less of a demand for alternative raw materials. Hemp is currently of little significance as raw material for paper, however it is still scarcely grown in the developed world. The long-term price for pulpwood has been low compared with any alternative except recycled paper. More about wood pulp technology in Bleaching of wood pulp.
The decision of the United States Congress to pass the 1937 Marijuana Tax Act was based in part on testimony derived from articles in newspapers owned by William Randolph Hearst, who had significant financial interests in the timber industry, which manufactured his newsprint. The background material also included that from 1880 to 1933 the hemp grown in the United States had declined from 15,000 to 1,200 acres (4.9 km²), and that the price of line hemp had dropped from $12.50 per pound in 1914 to $9.00 per pound in 1933.[18][19] In 1935, however, hemp would also make a significant rebound.[19] In the wake of this rebound, Hearst began a campaign against hemp, and published stories in his newspapers associating hemp with marijuana.[20] and attacking marijuana usage.[21] As a result of the act, the production and use of hemp was discontinued.
Characteristics of hemp fibre are its superior strength and durability, resistance to ultraviolet light and mold, comfort and good absorbency (8%).[citation needed] Hemp rope is notorious for breaking due to rot as the capillary effect of the rope-woven fibres tended to hold liquid at the interior, while seeming dry from the outside.[22] Hemp rope used in the age of sailing-ships was protected by tarring, a labor-intensive process and also the reason for the Jack Tar nickname for sailors. Hemp rope was phased out when Manila, which does not require tarring, became available.
There is a niche market for hemp paper, but the cost of hemp pulp is approximately six times that of wood pulp,[13] mostly due to the small size and outdated equipment of the few hemp processing plants in the Western world. Hemp pulp is bleached with hydrogen peroxide. Hydrogen peroxide can also be used for wood pulp. Kenaf is another fast-growing plant which can be used as a replacement for wood pulp. Kenaf paper has been produced in commercial quantities.[23]
A modest hemp industry exists. Recent developments in processing have made it possible to soften up coarse fibres to a wearable level.[24]
Harvesting
Hemp stem.
Smallholder plots are usually harvested by hand. The plants are cut at 2 to 3 cm above the soil and left on the ground to dry. Mechanical harvesting is now common, using specially adapted cutter-binders or simpler cutters.
The cut hemp is laid in swathes to dry for up to four days. This was traditionally followed by retting, either water retting (the bundled hemp floats in water) or dew retting (the hemp remains on the ground and is affected by the moisture in dew moisture, and by molds and bacterial action). Modern processes use steam and machinery to separate the fibre, a process known as thermo-mechanical pulping.
Fuel
Biofuels such as biodiesel and alcohol fuel can be made from the oils in hemp seeds and stalks, and the fermentation of the plant as a whole, respectively, but the energy from hemp is low compared with the volume of the harvested hemp. It does, however, produce more energy per acre per year than corn, sugar, flax, or any other crop currently grown for ethanol or biodiesel[citation needed].
Henry Ford grew industrial hemp on his estate after 1937[citation needed], possibly to prove the cheapness of methanol production at Iron Mountain. He made plastic cars with wheat straw, hemp and sisal. (Popular Mechanics, Dec. 1941, “Pinch Hitters for Defense.”) In 1892, Rudolph Diesel invented the diesel engine, which he intended to fuel “by a variety of fuels, especially vegetable and seed oils.