The Science Behind Cannabis Extraction Methods: CO2, Butane, and More

Cannabis, once a taboo subject, is now at the forefront of scientific research and innovation. With its growing acceptance for both medical and recreational use in various parts of the world, there's a growing demand for high-quality cannabis extracts. These extracts are the building blocks for numerous cannabis products, from oils and tinctures to edibles and topicals. Behind the scenes, a fascinating world of chemistry and technology is at work, determining the quality and safety of these extracts. In this blog, we delve into the science behind cannabis extraction methods, focusing on CO2 and butane extraction, among others.

The Importance of Cannabis Extraction

Cannabis contains hundreds of chemical compounds, including cannabinoids like THC (tetrahydrocannabinol) and CBD (cannabidiol), as well as terpenes and flavonoids. These compounds hold immense therapeutic potential, but they are not readily accessible in their natural plant form. Extraction is the key process that isolates and concentrates these valuable compounds, making them suitable for various medicinal and recreational applications.

Several extraction methods are used to achieve this goal, each with its own set of advantages and disadvantages. Here, we explore two common methods: CO2 extraction and butane extraction, to understand the science behind them and their implications.

CO2 Extraction: Supercritical Fluid Extraction

Supercritical CO2 extraction, often hailed as one of the most efficient and safest methods, is rooted in the principles of using carbon dioxide (CO2) as a solvent. In its supercritical state, CO2 behaves as both a gas and a liquid simultaneously, offering the best of both worlds for extracting cannabinoids and other compounds.

The Supercritical State

To understand supercritical CO2 extraction, it's essential to grasp the concept of a supercritical state. When CO2 is exposed to specific temperature and pressure conditions, it transforms into a supercritical fluid. In this state, it has the density of a liquid and the diffusivity of a gas, allowing it to penetrate plant material like a gas but dissolve compounds like a liquid.

The Process

 During supercritical CO2 extraction, ground cannabis plant material is placed in an extraction vessel, and supercritical CO2 is pumped into the chamber. Under controlled conditions, CO2 dissolves and carries away the desired cannabinoids and other compounds, leaving unwanted materials behind.

Selectivity

One of the advantages of CO2 extraction is its tunable selectivity. By adjusting temperature and pressure, it's possible to target specific compounds for extraction while leaving others untouched. This precision is crucial for producing extracts with desired cannabinoid and terpene profiles.

Safety

CO2 is considered safe for extraction, as it is non-toxic and non-flammable. Furthermore, the final product typically contains little to no residual solvent, ensuring a clean and pure extract.

Butane Extraction: Hydrocarbon Extraction

Butane extraction, also known as hydrocarbon extraction, is another widely used method for isolating cannabinoids and terpenes from cannabis plant material. Unlike CO2 extraction, butane extraction utilizes hydrocarbon solvents like butane or propane.

Solvent-based Extraction

Butane extraction is a solvent-based method, meaning that it uses butane as the primary solvent to dissolve and extract desired compounds from the plant material.

The Process

In a typical butane extraction process, cannabis material is placed in a vessel, and liquid butane is passed through it. As the butane flows over the plant material, it dissolves and carries away cannabinoids and terpenes.

Purging and Safety

After extraction, the butane must be removed from the final product to ensure safety and compliance. This involves a process called purging, where the extract is heated to evaporate the residual solvent. Proper purging is critical to avoid any traces of butane in the final product, which could be harmful if consumed.

Comparison of CO2 and Butane Extraction

Both CO2 and butane extraction have their strengths and weaknesses, making them suitable for different applications and preferences. Here's a comparative overview of these two methods:

CO2 Extraction

• Pros: CO2 extraction offers several advantages. It is considered safe and non-toxic, making it a preferred choice for producing cannabis extracts. Additionally, it provides high selectivity for specific compounds, allowing producers to target desired cannabinoids and terpenes effectively. CO2 extraction results in minimal residual solvent in the final product, ensuring a clean and pure extract that is safe for consumption. Moreover, this method allows for precise control over extraction conditions, enabling the fine-tuning of parameters to achieve the desired product profile.

• Cons: However, there are some drawbacks to CO2 extraction. The equipment required for this method can be expensive, which may pose a barrier to entry for smaller producers. Additionally, the overall extraction process tends to be slower when compared to certain other methods. Despite these challenges, many consider the benefits of CO2 extraction, including its safety and precision, to outweigh the associated costs and time investment, making it a favored choice for high-quality cannabis extracts.

Butane Extraction

• Pros: Butane extraction is prized for its speed, cost-efficiency, and potential for high yields, making it an appealing choice for many cannabis producers. However, it demands strict adherence to safety protocols due to the flammable nature of butane. Despite its advantages, butane extraction's safety concerns and limited selectivity compared to some other methods should be carefully considered when choosing an extraction technique for cannabis processing.

• Cons: Butane extraction comes with safety concerns due to the flammability and toxicity of butane, necessitating meticulous handling and well-ventilated environments to mitigate risks. Furthermore, the limited selectivity of butane extraction means it is less precise when it comes to targeting specific compounds, potentially resulting in a less refined final product compared to methods like supercritical CO2 extraction.

Other Cannabis Extraction Methods

While CO2 and butane extraction are among the most common methods, the world of cannabis extraction is diverse, and various other techniques are employed to create unique products:

Ethanol Extraction

Ethanol, a safe and food-grade solvent, is used to create full-spectrum cannabis extracts. It is particularly popular for producing tinctures and oils.

Rosin Pressing

Rosin pressing involves applying heat and pressure to cannabis flower or hash to squeeze out valuable compounds without the need for solvents. It's a solventless extraction method known for its simplicity and purity.

Olive Oil Extraction

This simple at-home method involves infusing olive oil with decarboxylated cannabis flower to create edible or topical products.

Steam Distillation

Steam distillation is used primarily for extracting terpenes from cannabis. It is a gentle method that preserves the delicate aroma compounds found in the plant.

Hydrodynamic Cavitation

A relatively new and innovative technique, hydrodynamic cavitation uses the physical forces generated by ultrasonic waves to break down plant material and extract compounds efficiently.

Learn More About the Benefits of Cannabis Extraction 

Cannabis extraction is a dynamic field where researchers and industry professionals continuously push the boundaries. Methods like CO2 and butane extraction are just a glimpse of the techniques transforming cannabis into valuable extracts for various products. As advancements continue, we can anticipate safer, more efficient, and eco-conscious methods shaping the future of cannabis extraction, catering to both medicinal and recreational needs, and delivering a diverse range of products to consumers.

Check out our Canna Club of Nichols Hills blog for more information about our exceptional cannabis products in Oklahoma City, OK.