Two of the most popular distillation methods whose product offers both a better flavor and experience is the short path distillation process and its cousin, the short path wiped film distillation process. Both achieve very similar results in different ways.
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The Short Path Wiped Film Process
Let’s take a look at how the short path wiped film distillation process works.
Where other methods employ solvents to help the extract material move or flow through the process, these systems take advantage of the melting points of cannabinoids instead.
These compact systems are set up with a feed vessel sending extract material into a heated evaporation vessel. Inside this evaporation vessel is a rotating wiper blade that evenly distributes the extracted material onto the vessel walls. The extract material only spends a short amount of time on the wall to limit heat exposure and any degradation of the material.
Image courtesy of Root Sciences
Inside the evaporation vessel at the center is an internal condenser. This is where the various parts of the extract material are split up and concentrated.
The close proximity of the condenser to the heated vessel wall provides a short path for the extract to travel to. Hence the name, short path distillation process. As the wiper system moves the extraction material down through the vessel, it evaporates to the condenser which converts it back to a liquid. This liquid is then collected at the bottom and is now a distillate.
Heavier materials like chlorophyll, sugars, salts, and wax fractions are unable to evaporate off the surface of the evaporation vessel wall, and so they travel, via the wiper blades, into a separate container which is also at the bottom. A separate and chilled evaporator captures the terpenes in their own flask.
The Short Path Distillation Process
The short path distillation process employs a setup that uses the same principles, just without the wiper system to distribute the extraction material.
Instead, a heated flask is where the extraction material is fed. Gradually, increased heat is applied to the extract material in the feed flask. A vacuum is also applied to assist in drawing the vapors up into the fractionating tubing. From the fractionating tubing, the contents then hit the condensing tube, where the fractions take separate paths.
As with the wiped film process, the weight of each fraction determines the collection flask.
Image courtesy of Buchi.
To further improve product refinement, each process can have the extract material run through them multiple times. Similar to the wiped film process, this setup is also relatively compact and lends well to multiple devices working simultaneously in a smaller space.
Benefits of Short Path Distillation
Flavor and “experience” are obviously more consumer-centered advantages, but for producers, there are many more that come with employing either a short path distillation process or short path wiped film distillation process.
One such production advantage is something called “continuous feed,” which is great for making large quantities of product for longer periods of time with greater consistency.
Where other extraction processes use heated beakers, continuous feed also allows for a greater degree of scalability to your production, which just isn’t much of an option with batch mode stills.
High evaporation rates allow for more distillates to be captured, while the relatively low processing temperatures (130-180°C) contribute to the fact that there aren’t any solvents needed to move the extract material through the process.
Most importantly, this system will separate cannabis into high concentrations of THC and CBD distillates. In fact, short path distillation can result in cannabis distillates that are 99% pure. So if you are trying to make a pure CBD product, for example, going with the short path distillation process is one of the best methods you can use.
The compact design of short path distillation systems makes them an ideal choice to use in operations where large quantities of multiple strains need to be extracted.
Lastly, these machines are easy to use and are largely automated in their function.
Now you know how these very similar distillation processes work and how they can benefit your production.
But how much does a short path distillation system cost?
There are several places to purchase short path distillation equipment from which, along with the kind of capacity they are capable of, can vary in price.
What you can expect is that basic turnkey short path systems start just under $3,000 and can move well past the $10,000 mark, depending on capacity and features.
Wiped film evaporators run between $5,000 to 40,000, also depending on capacity and features. If you have a large operation or are looking to scale up your production considerably, investing in a wiped film evaporator is the right choice, as it can handle larger volumes of product.
Isolate versus Full-Spectrum
Using the short path distillation or wiped film distillation process results in pure isolates — whether that be THC, CBD, or any other cannabinoid or terpene you may be choosing to distill.
Isolates are the purest and most potent form of the compound, and they have some benefits, like being completely odorless and tasteless. This is great if you are using these compounds in foods or beverages, for example, as it will not alter the taste in any way.
However, a growing body of scientific research has found that full-spectrum extracts have many benefits over isolates. The myriad of compounds found in cannabis work together to form what’s known as the entourage effect, which enhances the effectiveness of the medicinal properties.
As a result, you may want to take the pure isolates produced from the short path distillation process and use reverse chromatography methods that will result in a full-spectrum extract. This can be especially useful for creating highly effective CBD products, for example, as the end product can still have no traces of THC, but will still have many of the other beneficial compounds found in cannabis.
The beauty with using short path distillation is that you can isolate each specific compound, then combine them together in unique blends that will yield highly specific results. The possibilities are endless when you use technology as precise as short path distillation.