Methods and Machines to Assist a Crucial Component of Processing
The ability to properly dry hemp is one of the most important steps in hemp processing and production
operations. Even if high quality hemp is grown, failure to thoroughly dry the harvested plant material can
turn a profitable harvest into a lost crop overnight. Improper drying practices can result in crop damage
due to dust, dirt and pathogens, and total crop loss may occur as a result of mold from incorrect drying.
Proper drying is critical when storing material for processing for any downstream product from isolate to
distillate or smokable flower. As in most agricultural processes, the ability to quickly and cost effectively
dry the harvested material is a critical step in insuring farmers are able to recognize profit from months
worth of costly labor and inputs.
The rapid growth in the hemp industry in recent years has led to new developments in the tools and
techniques integral to productive and profitable hemp farming and processing operations. Outdated
practices are giving way to innovative systems designed to expand production capabilities and increase
quality control and repeatability. While more traditional ‘in the barn’ drying styles may still work in
smaller operations, large scale operation must consider advances in the methods and machines that can
help them reach and sustain success in an ever-competitive market.
Traditional Hemp Drying
The hemp drying process, regardless of method, begins immediately post-harvest to allow for the highest
potential of quality product. Traditional methods involve hanging whole plants and stems in a barn, shed,
or warehouse out of direct sunlight. The plants should be spread out and upside down while encouraging
equal airflow and ventilation throughout the drying facility. Fans and other climate controlling equipment
are often set up to allow for proper ventilation while maintaining ideal drying conditions. 60 to 70 degrees
F with a relative humidity of around 60% are desirable for encouraging adequate drying while optimizing
cannabinoid and terpene profiles. Plants should be hung individually or broken apart stem by stem to limit
the possibility for mold and mildew. While this drying method has been practiced for years, it is limited
in scope by a longer speed to market than current techniques and has an inherent risk for mold and other
crop destroying pathogens.
Modern Hemp Drying
Modern methods of hemp drying have led things out of the barn and into the future. New machines are
available to automate the process with greater control and higher throughput. Additionally, advances in
sensors and controls allow for a better visibility of the drying cycle, which can be used create ideal drying
conditions. Current machines vary in style and construction for desired needs and outcomes, but are
typically defined as either continuous or batch processes:
Continuous Dryers – high throughput systems that use a conveyor belt or drum to constantly dry
material. Often used for Biomass due to their output capability and input size requirements.
Batch Dryers – systems that hold one batch of material at a time to be replaced with new material when
dry. Often used for flower or higher yielding products due to their highly controllable environments.
These two styles of modern drying machines are being created with slightly different operating methods,
each slightly different from one another in capability and design.
Belt Dryers – High output and production units capable of drying large amounts of biomass quickly and
efficiently. Typical designs feature in-feed and out-feed conveyors leading into and out of a main drying
chamber where plant mater is dried as it moves through a series of mesh belt layers. These units offer
high volume production with precise electronic controls to create ideal hemp drying conditions. Fueled
by natural gas/propane these units fit well in most industrial or farm environments and offer a farm ready
drying solution relatively quickly.
Rotary Dryers – Drum style dryers that come in a variety of sizes from small and compact to large and
industrial. Plant material is placed in a rotating cylinder, which is heated to encourage drying. The inside
of the drum is lined with shoveling plates to pick up and move biomass. These units have been used with
other agricultural products for decades and the technology also works for hemp. Controls on these
systems are vary from basic to advanced and are typically fueled by natural gas. These units are often
very large and may require longer lead times for construction.
Drying Chambers – Typically designed as part of modern hang dry or rack drying operations. Drying
chambers typically include a combination of heat, airflow and dehumidifiers. This combination pulls the
moisture out of a closed space such as a drying room or container. The units can be set to desired
humidity and temperature levels but without proper controls can also draw moisture out to quickly
leading to over drying that can be detrimental to end product. These systems can be stand alone
structures or built into a building as part of the facility build out.
Current Offerings from Triminator
There are many options when it comes to choosing the best hemp dryer for a processing operation but
Triminator is leading the way with new technology and innovations designed to increase output for large
scale production facilities.
The Triminator Belt CBD Hemp Dryer is a continuous, high throughput machine designed to utilize low
heat and smart airflow to rapidly dry hemp leaves and flowers while preserving biomass CBD and terpene
profiles for maximum crop returns. The unit can dry up to 1,100lb/hour while using a proprietary heat
recapture system to retain up to 80% of the heat and cut operating costs up to 30%.
The Triminator CBD Box Hemp Drying System is an innovative batch dryer designed with low
operating costs and maximum efficiency. This box dryer uses an advanced control system to regulate the
drying chamber, creating a highly efficient drying curve for maximum control and optimal terpene
retention. Capable of processing up to 1,500lb/24hrs the unit is ideal for smaller operations or those
focusing on smokable flower.
When to Get a Hemp Dryer to Support Your Operation
Commercial hemp processors will see immediate benefit by adding an industrial hemp dryer to their farm
or facility. The efficiency and control of these machines allow processors to increase their speed to
market, eliminate the risk of crop loss and maximize their ROI and are an essential addition to a profitable
processing operation. Want to know more? Contact us today talk to one of our harvest solution experts.
Equipment Used in High Production Hemp Drying
Hemp is now benefiting from a resurgence in popularity thanks to high demand for CBD oil, and commercial items including paper, textiles, clothing, biodegradable plastics, paint, insulation, biofuel, food, and animal feed. It’s interesting to note that hemp oil is selling for approximately $1000 per liter. Expectations of the global industrial hemp market is projected to balloon to over $10 billion dollars by 2025.
Legalized as part of the 2018 Farm Bill, the Bill changed hemp from a controlled substance to an agricultural commodity. Hemp cultivation is attractive to farmers who have been impacted by the increases in tariffs on certain crops. Consumer demand, along with higher profits for farmers, are causing explosive growth. Hemp can be grown for its seed, fiber, or floral biomass.
Harvesting and drying of hemp is critical for CBD production. The presence of molds and mildews will lower the value of hemp floral biomass, so the harvest needs to be stabilized before mold, mildew, or decomposing can occur. Once hemp is harvested, it should be immediately moved to the drying facility to eliminate the moisture content in the harvested hemp.
On a small scale, historically hemp has hung in a barn to air dry, an inefficient process – and a slow one. To keep up with consumer demand, a more modern and systematic approach for efficient harvest and drying is necessary, relying on industrial hemp dryers.
Optimally, drying should begin within hours of the harvest. The wetter the hemp, the more urgent the drying process should be. The hemp industry has accepted 10% moisture as dry. For higher product quality, and safety for long term storage, a preferred level is 8-9%. Most of the moisture in hemp comes from broken plant material, immature seeds, and seeds encased in bracts.
New industrial dryers, some capable of processing 1000-4000 pounds of biomass an hour, and total drying control are being introduced to keep up with the consumer demand.
Batch dryers include drying chambers that usually are made up of a dehumidifier, an aerator, and a heat source. This product removes moisture out of a drying facility or a container. The energy efficient dehydration systems, designed to dry hemp, is a closed system that operates independently from ambient conditions. The combination of the heat driven dehumidification unit with a programmable controller that can be accessed remotely, plus airflow equipment creates consistent drying conditions inside the chamber.
The belt dryer has a conveyor into a large drying chamber. As dehydration is necessary to preserve the hemp biomass, mesh-belt hemp dryers continuously dry large quantities of plan materials in a short period of time, and without requiring much production footprint. These technologies allow the operator to adjust the thermal energy in the hemp dryer to evenly evaporate water without over drying or over heating the hemp. The fuel for belt dryers is via propane or natural gas. Designed for high output, the hemp dries as it advances through a collection of mesh layers. The use of electronic controls sets the stage for precise and optimum biomass drying conditions.
Rotary Dryers, the workhorse of industrial dryers, have been in use for many years. They also work well for drying hemp, typically via natural gas. Here’s how they work: the biomass is situated in a heated cylinder which rotates and tumbles the material, in the presence of drying air. The inside of the cylinder, or drum, includes plates to move the hemp. The electronic controls can be quite advanced, and these dryers can be very large. Again, they are designed to move large amounts of production throughput.
The Importance of Temperature Control
Irrespective of dryer type, temperature control is critical for maximum yield. Too much heat bakes the oil out of the hemp, wasting fuel and losing yield in the process. It is a delicate balance of maintaining temperature within a couple of degrees of setpoint, while moving green hemp through the dryer at the fastest rate possible. Goal is two fold – reduce moisture to 8-10% by weight without driving off the oil.
Keys to Precise Temperature Control
- Wide turndown burners with precise temperature control.
- Modulating gas control valves with .1 of a degree positioning accuracy.
- Process controllers and indicators accurate to .25% of span.
- 508A listed electrical panels, NFPA 86 compliant
- Secure digital recording of temperature and other key variables for contract drying.
- Access Combustion
- Air Monitor Corporation
- Eclipse Thermal Solutions
- Honeywell Kromschröder
- Honeywell Maxon
- Dungs Combustion Controls
- Siemens Combustion Control
- Fox Thermal Instruments
- Selas Heat Technology
- Itron Metering Systems
- Pyromation, Inc.
- Azbil North America
- Earthquake Safety Systems
- Lenox Instrument Company
- UL 508 Control Panels and Control Systems
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