Cannabis Grinding for High Process Efficiency
Milling the cannabis plant is the preliminary stage to extracting the cannabis oils. By grinding and milling the plant down to a fine and consistent particle size, the packing density is increased and a greater extraction efficiency can be achieved.
A grinder allows you to quickly and continuously feed large quantities of plant material through the machine. Its sanitary design allows for easy cleaning and helps to future-proof against more stringent industry regulation and standards.
> Increased output of downstream processes
> Improved quality of final product
> Precise particle size distribution
> Increased efficiencies
> High throughput
How to Grind Your Cannabis and Hemp for Extraction
As the old saying goes, size matters. And when you’re grinding cannabis or hemp for an extractor, size matters a lot. Grinding the plant material too small can create low-quality oil; grinding too large can leave valuable cannabinoids in the waste material.
Whether you’re extracting with supercritical CO2, hydrocarbons, or ethanol, finding the right particle size for your solvent and extractor will increase your returns and may even speed up your production.
Read on to learn how you can optimize your grind for your extractor, your strain, and your post-processing equipment.
Why Size Matters When Grinding Cannabis and Hemp
When you grind cannabis or hemp with an industrial mill, you’re increasing the surface area and making the cannabinoids and terpenes easier for the solvent to access. However, the milling also exposes the stuff you don’t want: chlorophylls and plant waxes. Those elements make the oil less desirable and increase the post-processing necessary for most final products.
A finer grind effectively lowers the selectivity of the solvent while increasing its power. The solvent grabs everything it can out of the plant material, and it does so very quickly. Depending on the solvent type, this can be a good thing. A smaller grind size speeds up the action of CO2. But for a powerful solvent like ethanol, grinding too fine can be a mistake.
A coarse grind — or no grind at all — will require more time to achieve the same extraction completion. Depending on the solvent, this can be a good thing. But for most production objectives, ethanol and hydrocarbons are plenty powerful. Running a small particle size may pull out too much wax and chlorophyll.
How Fine Should You Grind Cannabis and Hemp for a CO2 Extractor?
Cannabis and hemp should be milled to a particle size of 1/16” – 3/16” for CO2 extractors.
In general, CO2 could use a little extra kick for dissolving cannabinoids and terpenes. Grinding to a smaller size helps it pull out the good stuff at lower pressures (without the terpene-compromising high temperatures). And it helps in other ways too.
Because CO2 extractors run at super-high pressures (like 2,000 psi), the movement of the solvent through the material column can create “channeling.” When the particle size is too large or the grind is inconsistent, the solvent channels rivers in the material where it can flow through more easily. This leaves other areas of the plant material untouched and under-extracted.
The solution is a smaller particle size and a consistent grind. When all the plant material is evenly packed and homogeneously sized, the supercritical CO2 reaches all areas of the extraction column and retrieves all the oil possible.
So why the range of particle sizes for CO2? After all, there’s a big difference between 1/16” and 3/16”.
Production objectives vary from producer to producer, and so does the plant material. Some strains may require a smaller particle size and longer runs. Other high-potency strains may do better with a larger size and shorter runs because they extract more easily. The desired oil purity may play a role too. Shorter runs with a larger particle size yield a better oil — but less of it.
How Fine Should You Grind Cannabis and Hemp for an Ethanol Extractor?
Cannabis and hemp should be milled to a particle size of 5/64” – 1/4” for ethanol extractors.
Ethanol is a very powerful solvent. Extraction is quick and best performed at lower temperatures so that less chlorophyll and wax co-extracts from the material. A coarse grind is best, and some producers choose not to mill the material whatsoever. For most strains, the optimal grind size for ethanol is on the high end of the 5/64” – 5/16” range.
Another benefit of grinding for ethanol extraction is an increase in production capacity. Grinding also decreases the solvent necessary per pound. When plant material is ground, more material can fit in the extraction vessel per run, thus increasing production speed and reducing the ethanol that needs to be distilled in post-processing.
How Fine Should You Grind Cannabis and Hemp for a Hydrocarbon Extractor?
Cannabis and hemp should be milled to a particle size of 5/64” – 1/8” for hydrocarbon extractors.
Though the perfect grind for a hydrocarbon extractor can be a little larger or smaller depending on the strain, 5/64” – 1/8” is the sweet spot. Hydrocarbons like butane and propane are powerful solvents. Yet, because the solvent flows through the material under pressure, channeling can occur like it does with a CO2 extractor. The channeling problem is less severe, but it’s still best to avoid large particle sizes and unmilled material.
How a Cannabis Mill Works on Hemp and Cannabis
An industrial cannabis and hemp grinder can process hundreds of pounds of material an hour while maintaining a precise particle size for consistent results and optimal extraction completion.
A mill, such as the Mobius MBX Mill , typically uses a rotary mechanism and a screen or rasp. A rotor pushes the material across the screen or rasp, and the coarseness of the screen or rasp determines the particle size. Screens are best for coarse material; rasps, which are similar to a file, are ideal for smaller particles.
A good alternative for a coarse grind is a shredder — such as the Triminator ShredMaster , rotating blades tear apart the material. The resulting particle size — 5/16” — works well for ethanol extractors.
The days of FDA-mandated Good Manufacturing Practices (GMP) are quickly approaching, so it’s best if your mill is ready for GMP compliance. It should be stainless steel and easily cleanable. Cannabis and hemp are resinous materials — as you know — and processing equipment must be frequently cleaned.
If you’re ready for a precision cannabis mill that can handle your increasing production volumes, make sure to check out the Mobius MBX Mill .
And if you want to stay current on all the industry’s latest processing tricks, make sure to subscribe to the Mobius blog for frequent updates.
Grinding for CBD Hemp Oil Extraction
The extraction of cannabidiol (CBD) from hemp can be achieved through a wide variety of methods. It has been common within large-scale systems, capable of extracting CBD oil from thousands of pounds of hemp a day, to use liquid solvent systems with butane, alcohol, hexane, or ethanol. Liquid solvent hemp oil extraction systems often have lower capital costs but also have drawbacks which can include working with flammable materials and purity considerations with the finished oils. The use of carbon dioxide or CO2 extraction for hemp oil has more recently gained acceptance as a safer and potentially higher-yielding extraction method. CO2 extraction for CBD oil is not without its challenges which can include significant upfront costs and more sophisticated process control methods requiring much higher levels of operator knowledge.
Regardless of the CBD oil extraction method, the first critical step will be the sourcing and preparation of the hemp from which the CBD oils will be extracted. Depending on the desired end extracts, the source hemp may just be flowers and trim or it could be complete stalk material. JWC’s Monster Industrial shredders can play an integral role in getting the source hemp ready for CBD oil extraction.
Hemp Shredding for Preconditioning
Variations in the hemp feed material can present unique challenges during preconditioning prior to CBD oil extraction. The hemp source materials can have unexpected debris from harvest like wood, roots, rocks or other foreign matter. Different hemp strains and packing methods will drive variations in density and moisture content. Finally, the type of materials being used, like flowers and trim versus the full plant, can potentially disrupt the preconditioning prior to oil extraction.
JWC’s Monster Industrial shredders work with two rows of sharp steel cutters that rotate slowly and with incredibly high torque to break down even the toughest solids. They are powered with a quiet and efficient electric motor to grind full hemp plants or flowers and trim to the exact needs of any CBD oil extraction process. Our industrial shredders are designed to grind down wet or dry materials. They also include scrapers for self-cleaning the cutters, preventing unnecessary cleaning and maintenance.
Low Speed = Low Noise and Dust
Alternate technologies for breaking down plant materials like hammer mills work at high speed to pulverize the hemp by beating it with internal hammers. This type of equipment typically creates significant dust, especially with dried hemp, which equals lost feedstock materials within the operation. The high-speed operation can lead to more frequent maintenance. This equipment can also have an issue handling wet material as well as hard material. Finally, hammer mills are extremely noisy during operation. This creates an unpleasant work environment for the technicians that need to work around them.
JWC’s shredders work at low speeds – typically around 60 rpm. This means that there will not be excessive dust produced while the grinder is in operation. Additionally, the shredding of the hemp occurs by the steel cutters moving past each other which results in a much quieter operation during processing.
Customized to Extraction Process Requirements
The hemp preconditioning needs of a CO2 extraction process versus an ethanol extraction process can vary greatly. Our Monster Industrial shredders can be customized to the exacting needs of whatever extraction process you use. JWC has the flexibility to offer unique cutter size combinations that can get you the optimum particle size. We will also work with you on the perfect set-up of speed reducers and controls to make sure the feed rates and shredding power meet your expectations. Finally, JWC can offer feed hoppers and stands if required to better integrate the shredder into your oil extraction setup. We realize that the needs of every hemp processing operation are not the same.