The Difference Between Open-Loop and Closed-Loop Systems

When it comes to extracting from cannabis, ethanol extraction systems become the logical choice for those who want consistent results and large amounts of material. While more complex than rosin extraction, ethanol extracts eliminate the risk of things like burning the material or the need to apply significant pressure.

If you are considering the ethanol route for making extracts, there are a few things you need to know before proceeding.

Open-loop and closed-loop extraction are two popular methods for extracting desired substances from materials. Open-loop extraction is the process of removing a substance from a material in an unsealed system with an open tube.

Closed-loop extraction, on the other hand, describes a process that involves the extraction of material using a system that is completely closed to the external environment. To determine which method is best for your application, you should understand the key differences between open-loop and closed-loop extraction.

Closed Loop Extractor

Open Loop Systems

The open-loop system used for cannabis ethanol extraction is the most straightforward way to obtain an extract. The plant material to be used is placed in a tube with an open end, butane is poured over your material, and it is then steeped for extraction.

This process will take a few days and will not yield the best results because you need to allow the ethanol to evaporate naturally. It is possible to speed things up by heating the steeped cannabis, but this poses the risk of a possible explosion due to the ethanol and open flame. Likewise, heat will burn any flavor or aromatics.

Most importantly, it doesn't help when the solvent evaporates, but there will still be traces of ethanol or other solvents in the final product. Although usually in small amounts, these levels are not safe for medical purposes, although small tolerable amounts can still be used for culinary or recreational purposes.

The open-loop system also has the advantage of handling large quantities, provided you have a large vat to hold the cannabis and ethanol. You could argue that this system is moderately efficient in that it can handle larger amounts, but uses more ethanol.

Closed Loop Extractor

Closed-loop systems

Closed-loop systems are much safer than open-loop systems because they eliminate potential gas leaks by enclosing the solvent in the extraction system. These devices are required to pass safety standards set by the government before they can be sold to consumers. But in exchange, your oils contain no solvents of any kind, which makes them safer for use with medical-grade ingredients.

Closed Loop Extraction (CLE) symbolizes a dramatic shift in the way oil producers and consumers approach cannabis concentrates. The negative concerns about concentrates were mainly due to the lack of experience with extractors performing open-loop extraction; the extraction of butane was not in a sealed system and if exposed to an open flame, the gas could escape and cause an explosion.

For butane extraction, CLE is currently the safest method for extracting cannabis oil. It is a method where the extraction system is completely sealed and no gas is allowed to escape.CLE is also a more efficient extraction method.CLE systems are typically subjected to higher pressures than open-loop systems, which increases the time at the interface between butane and raw cannabis, resulting in a more complete extraction process. Part of the reason for this efficiency is that CLE systems allow the extractor to better control the temperature, which directly affects the solubility of THC in butane.

Open-loop extraction vs closed-loop extraction

Operational safety

One of the most significant differences between open-loop and closed-loop extraction is the safety of each process. In short, open-loop extraction poses more safety risks than closed-loop extraction. The increased risk of open-loop extraction is related to the fact that the process takes place in an unsealed system.

Since the extraction equipment has an open tube at the end, gases may escape during the process and increase the risk of harmful exposure or even explosion. However, closed-loop extraction occurs in a sealed-air system, eliminating the possibility of hazardous gases and flammable solvents escaping.

Quality of the end product

Another key difference between open-loop and closed-loop extraction is the quality of the final product. In an open-loop extraction process, the final concentrate is exposed to the solvent. As a result of this exposure, the purity of the extracted material is reduced. In a closed-loop extraction process, the solvent and the final product are never in contact, which means that the resulting extract becomes cleaner and of higher quality.

Efficiency

The efficiency of each process further separates them from each other. Ultimately, closed-loop extraction is more efficient than open-loop extraction from a time and cost perspective.

In terms of time, closed-loop extraction occurs at higher pressures and allows for higher temperatures, which means you can complete the process faster. In addition, because closed-loop extraction is performed in a closed system, you can reuse the chemical solvents involved in the process, ultimately saving you resources and money.

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