With Solvents like Ethanol
Method for Small Scale
The “Soak and Agitate” Method
The “soak and agitate” method is one of the most simple ways to start extracting cannabinoids from biomass! Though it has many trade-offs, which we’ll get into, it is a common method that many processors choose to start with.
The idea behind this method is again, simple. A stainless steel vessel, appropriately sized for your operation, can be used to mix solvent with biomass to perform the extraction process. Some may even have a mechanism for agitating the biomass while soaking in the vessel. Agitation can increase extraction efficiency, just like dipping a tea bag in hot water! Most will use micron bags for their biomass (just like tea bags) and this makes it much easier to drain the cannabinoid saturated solvent, remove the biomass, and start again.
This is where we have some of the biggest issues with this method. It’s not efficient to make a sustainable business out of it. Once your miscella is drained or strained out of the vessel, there is no mechanism to remove the solvent and cannabinoids that are still left in the biomass. That could be anywhere from 20% or more of your solvent and 20% or more of the cannabinoids left behind! This means extraction efficiency can be 80% or lower. This is a lot of wasted solvent and extract that can end up costing more in the long-term than what was saved in upfront capital. This all compounds to cause high production costs, profitability suffering, and an inability to compete at scale. We should also mention that we typically see this method being used for small scale biomass processing; i.e., 500 lbs/week or less, and is not recommended for larger scale operations due to safety hazards and the amount of solvent in process.
In summary, this method has the lowest upfront equipment costs to start extracting with ethanol and is probably the fastest to producing because it is simple; however, there are many downsides, such as, low extraction efficiency, extremely high solvent loss, high consumable costs, low volume processing capability, just to name a few. If you’re looking to extract for personal use, we’d recommend something like this in a tabletop size. If you’re new getting into the processing industry, TruSteel can help you maximize your equipment purchases, so that you can continue to use the very same starting equipment as you scale up!
Method for Mid Scale
This method is essentially the same as the “soak and agitate” method, but includes a twist. Or a spin! After soaking and agitating biomass in solvent, recovering the majority of the solvent can be done a number of ways. Most common is centrifugal seperation with a basket centrifuge. Think of your washing machine’s spin cycle. This action of using centrifugal force to “spin out” the water from washed clothes is the same process used to recover solvent and extract more cannabinoids from soaked biomass than the previous method discussed. This method is so efficient that most clients we work with see a 95-98% extraction efficiency and solvent recovery rate.
These basket centrifuges are great for medium sized processing facilities or commercial facilities processing 500-2500 lbs of biomass every day. Many of these systems incorporate a PLC and user interface for setting extraction parameters, monitoring the system, and increasing the level of safety to the processor.
Of course you pay upfront for that control and efficiency! Upfront investment can be 10-20x what is spent on some simple vessels, mainly because the centrifuge system must be designed for a hazardous location, due its electrical components and solvent handling. And just like the first method, you’re still limited to extracting in batches, each requiring a period of time to complete before manually unloading and loading a new bag of biomass.
In summary, this is the most widely used extraction method due to its high efficiency, level of control, and ease of use. Although the upfront cost is higher, it will allow for higher profit margins in your operation and typically much more processing capability.
Method for Industrial Scale
Inverting Basket Centrifuge
The cannabis industry is very much in its teenage years and much of the groundwork still needs to be laid for the industrial scale facilities to make sense in most markets. However, there is a big difference between the methods we’ve been discussing so far and the type of extraction method that’s going to be best suited for industrial scale cannabinoid extraction with ethanol. That difference is turning this batch process into a continuous one. Removing the manual processes and doing away with batch loading and unloading, because you know no one wants to operate 10 of those at once!
So, how do you process biomass continuously?
We have researched several continuous style extraction systems, including decanter centrifuges, screw presses, and even inverting basket centrifuges, such as Heinkel (technically not continuous but automated loading and unloading of the centrifuge).
Of all of these options, we recommend sticking to the centrifuge concept and going with a specialized decanter centrifuges or inverting basket centrifuge. The screw presses tend to damage biomass to the extent of over extracting impurities, such as chlorophyll, fats, etc.. causing more post processing after extraction.
When looking to build a facility that can process over 5,000 lbs of biomass day is the point when we would recommend looking at a continuous process. This method allows processors to further reduce processing costs by another magnitude, through lower consumable, labor, and energy costs all while increasing processing capability in a given day to hundreds of lbs per hour. And just like jumping from method one to method two, there is a large up front investment here. This investment gives processors the advantage of 95%+ profit margins at extremely high volumes, while having the ability to truly automate their process entirely and set the bar high for the industry.
Whether you’re considering dabbling in this industry and need guidance, future proofing your plans, or leading this industry, we can help you.
|Craft Scale (soak and agitate)||Commercial Scale (basket centrifuge)||Industrial Scale (inverting basket centrifuge)|
|Type of Process||Batch||Semi-Continuous||Continuous|
|Avg. Lbs/day Capability||100-200||150-3,000||3,000+|