The Definitive Guide to Cannabis Distillation
Distillation in General
Distillation is a refinement process that utilize the thermodynamic properties of the feed materials and further purify them. In the case of cannabis distillation process, highly purified cannabinoids such as THC/CBD distillate can be obtained.
Depends on the operational parameters, quality of feed material and the equipment used to perform distillation, potency of cannabis distillate can range anywhere from 75% to 99% purity in general. Below is a thorough breakdown of cannabis distillation process and general types of distillation.
Cannabis Distillation Category
Distillation Scienceshow me
Short Path Distillationshow me
Fractional Distillationshow me
Distillation Science Explianed
Distillation is the last process before remediation in cannabis processing flow. Distillation is proven to show that it can generate the higher purity of product with decent yielding.
The basic principle behind distillation is separation of components by different boiling points. It starts with the conversion of the feed material into a vapor and then condense it into liquid form under controlled temperature and pressure when it passes through the condenser column. Vapor will condense back into liquid form in the condenser column and be guided to a collector flask and therefore finishes a simple distillation process. Check the video below from Professor Dave for animated demonstration of distillation process.
SHort Path distillation
What is Short Path Distillation?
Short path distillation is a distillation technique that utilizes reduced pressure to have component with lower boiling point to travel a short distance and condense onto the condenser column and therefore achieving distillation purpose. Since the distance traveled by the evaporated component is very short, normal a few centimeters, it is called short path distillation.
Advanced Short Path Distillation:
Wiped Film Distillation
Wiped film distillation is also known as wiped film short path distillation. Another nomenclature commonly used for wiped film is wiped film molecular distillation since the separation happens at molecular level and precision where distance traveled for the vapor between evaporator and condenser is within the order of average free path length of the molecules. Wiped film distillation is so far the most effective molecular distillation technique.
Wiped film distillation is a generally compact. Such distillation process starts with the feed material within a flask being pumped into a heated evaporation column. There are evenly distributed wiper blades, mostly made of high quality PTFE material, create turbulent thin film onto the wall of the evaporation column. The feed material stays only a short period of time contacting with the wall to allow heat transfer take place before separation. The short exposure duration to heat is ideal for heat sensitive components such as cannabinoids, and avoids thermal degradation. When evaporation starts, the lighter boiling point material becomes vapor and it will travel a short distance before it gets in contact with the condenser column located inside the evaporation column. Vapor quickly cooled down and back into a liquid state. Concentrated components follows the condensation pathway to a collector. Other higher boiling point materials moves downwards under the force of gravity and turbulence caused by the wiper blades. Thus, the distillation is completed and crude materials gets separated.
One of the biggest advantages of wiped film distillation is the reduced exposure duration to heat. As a short path distillation, wiped film distillation process can also obtain reduce boiling point of targeted substance by reducing the operating pressure. Such reduced boiling point allows thermal separation of products without thermal degradation and long residence time. The wiped film generates a turbulence to evenly distribute the thin film to optimize evaporation surface area and downward force to push higher boiling point substance to move down, and therefore increase the overall separation efficiency.
What is fractional distillation?
Fractional distillation is another type of distillation technique that widely used for botanical extraction refinement, specifically for cannabis. The feed material is going to be separated into different component parts. The general principle for fractional distillation is very similar to that of short path distillation which is to utilize the differences of boiling points of components to evaporate and condense them separately.
The whole working process of fractional distillation starts with heating the feed material so that the material evaporates. On top of the feed material flask it is connected with a fractionating column, which cooling agent will around the column and provides the cooling effect at the internal column surface. As the vapor gets in touch with the column, the higher boiling point materials condense back into liquid form where the low boiling point materials are going to keep evaporating upwards. As the vapor travels along the column, it the high boiling point substances will be condensed and falling downward, back into the originate. The low boiling point substance will evaporate and flow into the condenser that branched out at the top for collection purpose. All substances will be separated to different ratio along the pipe, and such phenomenon is called theoretical plates. The more plates with finer control of temperature will allow finer separation. Therefore, a pure fraction of the substances is achieved through such distillation process.
Types of Fractional Distillation Equipment
Spinning Band Fractional Distillation
Spinning band is built upon the base of simple fractional distillation with further improved processing efficiency. Instead of empty fractional column or the packed column, spinning band distillation equipment has a helix type rotating instrument in the center of the fractional column. The band is normally made of Teflon or metal. Teflon spinning band normally operates under 225 °C. Temperature above that would cause deformation of the Teflon band and therefore metal band is required. During operation, the spinning band can create a turbulence and force the rising vapor to get close contact with the condensate. Such contact would increase the separation efficiency.
Distillation process has huge commercial potentials when it comes to the cannabis market. Below is a short list of cannabis derivatives thanks to the distillation technology.
Cannabis Distillates can be directly used as smokables. With the booming of the electronic smoking device market, cannabis distillates are working its way out to catch out with the consumption of flowers. Lots of great brands in the recreational markets are utilizing distillation technology to fulfill their orders in house.
Edibles is another great market that should not be underestimated. High purity distillate contains no odor nor flavour, which is ideal to serve as an ingredient for cooking. This opens up the opportunity for consumers who have a bad impression towards smokables but want to get a taste of the medicinal effects of cannabis.
Cosmetics & Topicals
Cosmetics market is giant and lucrative, and this is the main reason that many people are rushing into the cosmetics industry with cannabis infused products. With no direct consumption behavior and dissolved through subcutaneous infiltration, cosmetics are considered safer than smokeables and edibles. Cannabis distillate contains high purity cannabinoids which chemical structure wise can dissolve in lots of cosmetic formulation, and this enables the huge advantages and drive force for more and more business and consumers to come into the market and experience the magics of cannabis plants.
Pharmaceutical industry has been aware of the beauty of cannabis plants and the medicinal benefits it could bring. In order to R&D for better formulation, distillation process to obtain the highly purified ingredient is a key.
Feed Material Constituent
Understanding the constituent of feed material is important for operational planning and anticipation towards final products. The constituent of feed material varies depending on the extraction method and refinement process. Below is a chart that categorize general constituents result from different extraction method and refinement process.
Tips for Distillation Operation
Now you understand the basics of distillation process. Below are some tips and tricks that might help you improve overall distillation efficiency during operation and increase yielding, which eventually bump up your revenue.
Improve the Quality of Feed Materials
First of all, as stated before, the quality of feed material is one of the most important factor that will affect distillation efficiency and the quality of distillate at the end. Rule of thumb here is to limit the number of substances in the feed materials. More substances means more interaction between molecules during distillation process, which would either downgrade processing efficiency, cost much longer process time and potentially clog the column(s), or contaminate the end products. For instance, some terpene and fatty acids would have similar boiling point to cannabinoids. These substances would bring an awful burning taste and weird smell to the final distillate, which is highly undesirable. Refinement processes such as decarboxylation and filtration will greatly improve the quality of feed material, therefore is highly recommended.
Reduce Heat Exposure
Heat plays a big role during distillation process. It can evaporates the material, but so will it cause thermal degradation. Select the heating surface materials with greater heat conduction property can help with heat transfer efficiency and reduce heat exposure time to materials.
Cannabis Components Boiling POint Reference
At the end of the day, the operational procedure and quality of equipment determines the final result, emphasis on which distillation method to use plays little impact.