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What is CO2 Extraction and how is CBD extracted?

Date 26th May 2021

What is CO2 Extraction and how is CBD extracted?

If you've shopped around for CBD products in the past, you've likely encountered the term "supercritical CO2 extraction."

This refers to how CBD and other cannabinoids are harvested from cannabis crops. There's more than one way to do this, and CO2 extraction is considered the gold-star method for yielding high-quality, cannabinoid, and terpene-rich extracts without using harmful solvents that could remain in the final product.

We'll take you through a closer look at the extraction process right here and spend a bit of time comparing this process from other popular extraction methods. 

What Is Supercritical CO2 Extraction?

Let's break down the terms.

CO2 is the chemical formula for carbon dioxide. You're likely familiar with this chemical formula because it's a byproduct of cellular respiration and photosynthesis. It's what we breathe out and what plants convert into fresh oxygen.

Under high pressure and a certain temperature (1071 PSI and 87.98°F (31.1°C), CO2 enters a supercritical state where it's no longer a gas and not quite a liquid [1]. Supercritical carbon dioxide behaves as a solvent, without the inherent dangers of using a solvent like toxicity, risk of explosion during the processing, and negative environmental impacts.

Neurogan CBD Oil and Gummy Squares

What Are The Benefits Of Supercritical Carbon Dioxide For CBD?

Humans have been using cannabis for thousands of years. 

One of the oldest methods of separating the active compounds from the large plant matter (as an alternative to smoking the plant) is to heat it with cooking oil at a low temperature. While it's an effective method for small batches or for at-home use — like for making cannabutter — it's not the most efficient way to extract all the compounds from hemp for mass production.

Solvents are another popular method employed but they can be dangerous to work with. Let's get into some of the reasons why supercritical CO2 is the gold standard for the hemp extraction process. 

CO2 Is Non-Toxic

Carbon dioxide (CO2) is a non-poisonous gas, which means working with it for cannabis extraction is a lot safer than petroleum-based solvents like butane or propane.

A lot of these solvent methods require post-processing to strip away any remnants of these solvents because they are toxic. The problem is not all manufacturers take the extra precaution to ensure their hemp extractions are clean and safe.

The CO2 extraction process leaves zero traces of residual solvent, which means you're left with a clean hemp-derived extract to use for making CBD oil, capsules, gummies, skincare products, and vape juices.

Ground Hemp Flower For CBD CO2 Extraction

CO2 Extraction Allows For Precision

Working with supercritical CO2 requires specialized extraction equipment, so it's not a project you can do at home.

CO2 extraction equipment is expensive, but it allows precision adjustments for temperature and pressure to manipulate the state of CO2 into subcritical and supercritical.

At lower temperatures, the state of CO2 gas changes into a liquid. These microfine adjustments in pressurized carbon dioxide can significantly impact the final outcome of the extract. For example, some cannabinoids and terpenes are heat sensitive, so working at a high temperature can result in losing some of these beneficial compounds.

What you'll also notice in CBD oils using this CO2 extraction method, is the flavor profile. The aroma and flavor are in the terpenes of the cannabis plant and can lend their own set of effects. These compounds are highly sensitive, but by using precise CO2 extraction, you can preserve more of these terpenes for flavor and health benefits. 

CO2 Is Non-Flammable

Traditional solvent extraction methods are vulnerable to leaks, making them prone to ignite when exposed to a spark or flame. In 2014, there were a reported number of 32 explosions from butane extraction facilities in Colorado [1].

This lead lawmakers to impose stricter guidelines for workers' and environmental protection to reduce the chances of solvent explosions.

We won't dive into a chemistry lesson here, but to put it simply, carbon dioxide doesn't burn. For some visualization, it's like trying to burn log ashes. Its potential energy for combustion is used up, so it's not capable of burning again. 

The Process Eliminates Other Contaminants In CBD Extract

The other benefit of using the CO2 extraction process is that the pressure and temperature eliminate microbial bacteria, insects, mold, and mildew that may have been present on the plant. This helps to make sure that what you're consuming is cleaner and healthier for you. 

The Process Eliminates Other Contaminants

How Does Supercritical CO2 Extraction Work?

CO2 extraction requires specialized machinery to transform CO2 gas into a supercritical state under high pressure and temperature. CO2 as a supercritical fluid behaves like a solvent without the dangers of working with butane or methanol.

You can essentially, "wash" the harvested plant material with the supercritical fluid where it strips away the large plant matter from the tiny resin-like compounds that are rich with cannabinoids and terpenes in a large sealed chamber where temperature and pressure are fine-tuned.

CO2 extraction yields a thick, resinous extract similar to that of thick peanut butter.

The next step involves winterization or cold treatment to refine the cannabis extract. This helps to remove plant waxes, esters, and chlorophyll for a more pure resin.

The product from CO2 extraction is a raw full spectrum cannabis oil that's extremely potent. To make the full spectrum CBD extract easier to consume, it's formulated into CBD oils, capsules, gummies, or any other CBD product you can find on the market. 

Is Ethanol Extraction Better Than CO2?

Ethanol extraction is another way to produce safe and clean CBD extracts from raw plant material, and it's used in the medical and cosmetic industry. Ethanol is a simple alcohol made as a byproduct of plant fermentation. As a polar solvent, ethanol is useful for dissolving fat-soluble compounds (like cannabinoids and terpenes).

Ethanol is considered an efficient method for extracting a wide range of cannabinoids and other beneficial compounds from hemp, while still being relatively safe to work with.

Some manufacturers argue that ethanol extraction is much more effective than CO2 extraction methods, but it's not entirely without its flaws. Ethanol is more likely to retain chlorophyll from the hemp plant due to its polarized nature, which means it can taste much more earthy or grassy if it doesn't undergo multiple processing steps for refinement and filtration.

Additionally, ethanol is an alcohol-based solvent, which poses a fire risk. Ethanol extraction requires hazardous waste material, which needs to be properly disposed of and transportation of this solvent is highly regulated.

Is Ethanol Extraction Better Than CO2?

How To Buy High-Quality CBD Oil?

It's no secret that the cannabis industry is a bit of a Wild West.

It lacks consistent regulation, and you rely on manufacturers putting consumer's best interests before their own, but that's not always the case.

While independent lab testing isn't a requirement for CBD products, it's becoming more of an industry standard for brands that take their products seriously.

Independent labs have no affiliation with CBD companies, so the results of their findings are unbiased.

Independent or third-party lab tests provide a Certificate of Analysis for extracts that show:

  • Cannabinoid profile and potency
  • Terpene profile
  • Solvent residue
  • Pesticide residue
  • Mycotoxins
  • Mold
  • Other potential contaminants

Solvents, pesticides, and other contaminants can lead to irritation and other bad reactions, so it's extremely important that you reference a product's Certificate of Analysis before making a purchase. Most online CBD brands have this posted somewhere on their website, which is why we recommend shopping online, where you have access to this over walking to your nearest head-shop or grocery store.

What Is Supercritical CO2 Extraction?

Final Thoughts: CO2 Extraction For CBD

Cannabis consumers can enjoy many different products from edibles, sublingual oils, smokables, and topicals, on the market thanks to these technological advancements in extraction that allows manufacturers to yield higher amounts of hemp extracts from crops with more control over the final outcome's effect profile.

CO2 extraction has become the gold standard for cannabis extraction because of its overall safety for workers, the consumers, and the environment. It uses pressurized CO2 gas at certain temperatures and pressures to separate cannabinoids and terpenes from the large, organic plant matter, leaving behind a rich, cannabis concentrate with a diverse range of beneficial compounds

Unlike other extraction processes that involve solvents such as butane, CO2 doesn't leave behind any dangerous residue that may result in irritation or adverse reactions—all you get is high-grade CBD extract, the way it should be consumed, with a balance of other phytochemicals.

When shopping for CBD products, it's good practice to reference a company's independent lab tests to ensure what you're getting reflects the marketing on the bottle. A brand that hides their extracts' lab reports, or forgoes this step altogether is a red flag.

While testing isn't a requirement, it demonstrates a company's overall business integrity and commitment to their consumers in a space that's notoriously overrun with people who want to make a quick buck at the expense of your well-being.

If you're interested to learn more about the CBD industry, the benefits of CBD, and other relevant industry news, you can check out more articles like this on our blog or sign up for our Inside Scoop to get insights sent straight to your inbox.

Resources:

  1. https://www.coleparmer.com/tech-article/supercriti...
Katrina Lubiano
Katrina Lubiano

Katrina Lubiano is a content writer in the health and wellness space based in Vancouver, Canada — Canada's epicenter for cannabis culture. When she's not working, she enjoys sailing, watercolor painting, and cooking.