From hemp milk to hempcrete, hemp fiber, and biofuel, there are thousands of uses of the Cannabis Sativa plant. With the passing of the 2018 Farm Bill into law, which legalized hemp on a federal level, the hemp market is poised to become a multi-billion dollar industry.
The reason why there is such a wide variety of industrial hemp products is that each component of the hemp plant can be used from the roots and leaves to the flowers and stalks. Because of the various applications of the industrial hemp crop, harvesting methods and processing will depend on the final product. In this guide, we will talk about the different parts of hemp crops, how they are used to make various types of hemp products, and how they are processed.
The Different Uses of Industrial Hemp
As the hemp plant’s most versatile part, the stalk can be used to make everything from paper and clothing to rope and building materials. The hemp stalk can be broken down into different components that can be used differently. For example, its bast fibers can be removed to make textiles, which are often blended into other fibers.
The stalks and stems can also be processed for CBD extraction for low THC CBD production. One of the reasons why hemp was legalized with the passing of the Farm Bill is because hemp, unlike marijuana, has very low THC levels. It’s the high THC content in marijuana that makes it psychoactive. For CBD hemp to be legal, it should not contain more than 0.3% tetrahydrocannabinol (THC). To ensure this, the processing plant may also conduct THC testing.
The hemp leaves and flowers can be used for food products like teas. They can also be pressed for their rich seed oil. Hemp oil is extracted directly from hemp flower seeds. These seeds also have a variety of uses and are often sold in health stores as a superfood. They can take the form of supplement powders or be used in bread, beer, cooking oils, milk, and flour.
The roots of the plant are often overlooked. However, the roots have been used for thousands of years for their medicinal properties. The roots typically go through juicing and boiling processes. They often also end up as biomass. Hemp biomass is leftover raw materials that can be used in a variety of ways. Many hemp farmers sell wholesale biomass to concentrate processors who make specialized products like hemp oils, CBD oils, CBD isolate, and CBD distillate. The biomass can also undergo a fermentation process that turns it into hemp ethanol or energy fuel.
Regardless of the intended use of the hemp harvest, the plant will go through cleaning and drying to prepare it for the processing plant. The hemp stalks will go to a decortication plant or retting facility while hemp flowers, buds, and seeds will go through bucking or de-budding and de-hulling.
Hemp Flower and Seed Processing
Timing is everything when it comes to growing hemp for seed or grain production. What makes harvesting hemp for its seeds difficult is the different maturation rates of the different parts of the same plant. It is not uncommon for seeds at the top of the plant to already be split open, signifying maturity, while the seeds lower down will not be ready for harvesting. Therefore, the goal is to harvest when the risk of seed loss is lowest. Harvesting hemp prematurely can result in non-viable seeds and loss of product.
When hemp farmers determine it’s the optimal time to harvest the plant, bucking machines or destemmers/debudders are used to cut the flowering head from the plant. The plant is sorted, separating the parts – flowers will go to seed production processing, while stalks will go to fiber processing.
Matured seeds will be split open, making careful handling of the hemp seeds vital to maintaining the integrity of the seeds. They need to be removed from the flower head gently. Whole hemp seed will have a crunchy, outer shell that will need to be removed through a de-hulling process. In the past, de-hulling was done by hand, making the manual process of de-hulling tedious and prone to product loss. Today, modern de-hulling machines use gentle vibration to remove the seed’s hard outer shell. The machine also cleans hull residues and collects kernels for disposal.
The seeds may either go to storage or move to another phase in the facility, depending on the hemp processing plant. Before storage or packing, the hemp seeds will go to cleaning and hemp drying facilities. Low impact conveyors are crucial at this point to prevent damage. For this reason, the industry is increasingly eliminating the use of traditional conveyance methods that have proven to lead to product loss and wastage, such as augers and bucket elevators. For example, vacuums may run too fast with little control, bucket elevators require excessive maintenance, screw augers ruin the seed’s integrity by grinding action, and pneumatics cause inefficient usage of available energy.
Hemp Stalk Processing
Hemp farms begin harvesting for fiber production when the plants are in early bloom. For generations, hemp harvesting was performed manually. They would separate the bast fiber from the hurd by hand. Bast fiber is strong, which explains why it is the part of the plant used to make rope and canvas like that of boat sails. Because the fiber is incredibly strong, the process was painstaking and required a lot of strength. Thanks to technology, manually separating the raw fiber from the hemp stalk is no longer necessary.
Today, separating the bast fiber from the hemp plant’s woody core, or the hurd, can be approached in two ways. The first is through a mechanical process called decortication. Decortication equipment removes the woody interior from the stalk’s fibrous exterior. After hemp decortication, the fiber is scutched using a scutcher in preparation for spinning. The process also removes any impurities or residue, such as seed or hurd particles. The result is long lines of fiber that will be hackled or combed to remove broken fibers and align the fibers.
The other way to process the hemp stalk for fiber production is through retting, which breaks down the bark tissue that binds the natural fiber to the stalk. There are various retting methods, including dew retting, water retting, warm water retting, green retting, and chemical retting. Of the retting methods, dew retting takes the longest as it takes up to five weeks. Water retting takes 7-10 days, while chemical retting takes as little as 48 hours.
How hemp manufacturers process hemp depends entirely on the final product. Different uses of the hemp plant mean different equipment and methods to process industrial hemp. What they all have in common is the need for advanced technology and equipment to minimize wastage, eliminate contamination from pests and diseases, meet legal hemp regulations, and maintain product quality.