What Is Closed-Loop Ethanol Extraction in the Cannabis Space?

Despite so many states giving the green light to both medical cannabis and recreational marijuana, not every bit of cannabis and marijuana is sold as flower. In fact, tons of cannabis plant material is processed every year to make things like medical cannabis vapes, CBD tinctures and oils, etc. Making all these non-plant products requires extracting the desired compounds from plant material.

Closed-loop ethanol extraction is one means of getting cannabinoids, terpenes, and other substances out of cannabis plants. The process requires specialized ethanol extraction equipment produced by companies like Texas-based CedarStoneIndustry. Indeed, many states require that ethanol extraction be handled in a closed loop system.

Open vs. Closed Loop

It is easy to understand closed-loop ethanol extraction in the cannabis space if you understand the basic differences between closed and open systems. So let us step away from cannabis momentarily and talk about something else. Keeping food cold on a hot, summer day makes for a particularly good example.

An open system is one in which input and output don’t affect one another. An open system is linear. In terms of keeping food cold, a plastic cooler filled with ice is an open system. Input is provided by the ice or ice packs. Output is the work the ice packs actually do. Neither one affects the other.

On the other hand, an electric refrigerator is a closed loop system. Here, keeping food cold is not linear. A refrigerator is designed to both cool air and monitor internal temperatures. When those temperatures get too warm, the refrigeration system automatically kicks in. In a closed loop system, input and output are intrinsically affected by one another.

Closed-Loop Ethanol Extraction

With the understanding of open- and closed-loop systems, we can talk about closed-loop ethanol extraction in the cannabis industry. Ethanol is used as a solvent to separate cannabinoids and other desired compounds from raw plant material. The ethanol slowly degrades plant material to release the desired compounds.

In an open system, raw plant material is soaked in ethanol. The liquid solution is then evaporated and condensed to separate out CBD, THC, and so forth. This effective but highly inefficient means of extraction is practiced by DIY enthusiasts and small producers in states that do not require closed-loop extraction.

A closed loop system utilizes an extraction tank into which both plant material and ethanol are introduced. The tank is airtight and pressurized in order to control temperature, pressure, and moisture levels. And like an electric refrigerator, a closed-loop extraction tank is fitted with gauges that constantly measure what is going on inside. The tank can self-adjust to make sure everything stays on target.

Protected Against Contamination

In addition to efficiency, there is another reason for choosing closed-loop ethanol extraction: a closed-loop system protects against contamination. With plant material and solvent sealed in a pressurized tank, the likelihood of external contamination goes down significantly. Of course, operators still have to make the effort to clean and sanitize their systems on a regular basis.

A closed-loop system also makes for more consistent results. This is ideal for processes looking to extract and separate more than a hundred cannabinoids and terpenes. Closed-loop extraction allows for very specific extraction formulations that naturally lead to more exacting retail products.

As medical cannabis and recreational marijuana continue to spread across the U.S., they are opening doors to all sorts of tertiary industries supporting everything from growing to processing to packaging and shipping. Manufacturing closed-loop ethanol extraction equipment is just the tip of the iceberg for companies looking to cash in on the growing cannabis industry.

Colton Eva
the authorColton Eva