Complete Guide to CO2 Hemp Extraction

hemp extraction services

Most recreational and medical users of cannabis prefer to inhale the cool and instantly rejuvenating vapor that’s infused with cannabinoids instead of harsh smoke.

If you’re someone who prefers a purer, cleaner, tastier, healthier, safer, and a truly high-quality hemp or cbd concentrate, read on. We have a treat for you, and that’s the Supercritical Carbon Dioxide (CO2) extraction.

But that’s not really the treat, actually. Instead, it’s an awesome way of removing all those toxins that make the hemp great coming from the plant matter where it resides. In doing so, there’s no longer a need for you to burn your marijuana to reap the benefits.

Best of all, those health-conscious cannabis users out there would be pleased to know that the process of cannabis extraction will not leave any trace amounts of toxins on the finished product. That is something worth taking notice of.

In this article, we’re going to break down information regarding the basics behind the supercritical method of extracting fluid, including the biochemical benefits that come with carbon dioxide extracted CBD concentrate. This article will also include instructions on the simple process of extracting your own Kief crystals at home with the use of dry Carbon Dioxide ice.

The Added Value of Carbon Dioxide (CO2) Extraction

The supercritical extraction of CO2 is used increasingly as a recyclable, cheap, and environmentally safe way of producing high quality:

  • Hemp distillate oil
  • Coffee
  • Fragrances
  • Fruit and nut aromas
  • Fruit and nut extracts
  • Hop-oil extraction for beer
  • Oil extractions from algae for use as an alternative energy source
  • Omega-3 oils
  • Perfumes
  • Tea
  • Tobacco extractions used for e-cigarettes
  • Vanilla
  • Essential oils

When you look at the list above, you might find yourself pleased at the fact that CO2 extraction can be used for various products. But do you know exactly why it’s deemed so popular? Read on to find out.

  1. Our bodies produce carbon dioxide (CO2) naturally. When we breathe, the CO2 will be considered a natural product in comparison with chemicals like the CFCs or chlorofluorocarbons.
  2. The Food and Drug Authority or the FDA, believe it to be safe and this is why CO2 is being used for various things and that even includes keeping our soda fresh.
  3. The CO2 is not a toxic substance, and the process of CO2 extraction won’t contribute towards the increase of carbon emission in the atmosphere.
  4. CO2 extraction will not trigger any flammable petroleum-based solvents such as butane to get into contact with your medications. As such, any danger of explosion resulting from the extraction of CO2 will be prevented.

Now that it’s clear why the carbon dioxide extraction is a great process let’s dig deeper into the science behind how it works.

What You Need to Know About Supercritical CO2 Extraction

The following explanation might seem a bit complicated if you’re not an industrial chemist, but here it goes.

The carbon dioxide extraction machines work by essentially freezing and compressing the CO2 into a state where it becomes supercritically cold.

What does this really mean?

In a standard pressure and temperature, the carbon dioxide usually works as a gas. This gas will be changed to solid without exerting too much effort. The solid state is what they call the dry ice, and these are the two most common phases of the Carbon Dioxide that appears out of a lab.

Using a special type of equipment, you should be able to transform the CO2 gas to liquid by increasing the pressure up to 75 pounds for every square inch and by maintaining the temperature to less than -69 ℉. This is the starting point for the CO2 extraction process.

From the liquid state, the temperature and pressure will have to be increased past a certain point. We don’t need to dig deeper on the numbers here as it will turn out to be very complicated to understand but you need to know that if you’re going to increase the pressure and the temperature of the liquid Carbon Dioxide, the fluid will end up being in a supercritical state.

What this means is that it could adapt to properties midway in between liquid and gas at the same time. It sounds mind-blowing, right? The supercritical fluid is well capable of filling a container such as gas and still maintains its density similar to the liquid.

The supercritical property of the Carbon Dioxide is ideal for the process of chemical extraction since it’s gentler when compared to the other compounds. Thus, it will not cause any damage during the process. And since the solubility of the carbon dioxide varies according to low or high pressure, the supercritical CO2 can be used in extracting a selection of compounds instead of a combination of all compounds with just minor adjustments.So now that you have a bit of an understanding regarding supercritical fluid extraction (SFE), let’s now talk about how it can be used to produce hemp extracts.

Is the Supercritical CO2 Extraction System Better Than Others?

The CO2 extraction method is considered the superior extraction technique because it doesn’t require solvents. Conscious hemp consumers have concerns about residual solvents in their hemp products, which is valid. Who would want residual solvent in a wellness product? 

Some solvents can also damage sensitive compounds, like terpenes, within the hemp flower. This means that solvent extraction may work against the entourage effect by losing aromatic compounds. Cannabinoid-rich trichomes may also break off throughout the process, accidentally getting whisked away with residual solvent or excess plant material. 

Ethanol Extraction

Ethanol extraction is the process of using food-grade alcohol to absorb the cannabinoids from hemp. It also works to make extracts for cooking or baking. You may be familiar with ethanol extraction if you’ve used vodka or Everclear to make cannabinoid tinctures. 

Hemp plant material, including the leaves and stalks, is placed into a solvent bath within an extraction vessel. The solvent extracts the fatty acids and waxes from the plant, leaving the plant material behind. The plant material is removed from the mixture, the solvent evaporates, and the hemp extract is left behind.

If this method leaves residual solvent behind, the solvent is technically safe. Food-grade ethanol can’t hurt you if you ingest it in very small amounts. The biggest drawback to ethanol extraction is the evaporation process used to remove the solvent. 

This process will inevitably take away some of the terpenes from hemp. The end product will still be a full-spectrum hemp product but won’t be as complete as a solventless extract.

Butane or Propane Extraction

We won’t get into the specifics of butane or propane extraction techniques because they’re super dangerous. Although many people attempt to make butane hash oil or similar extracts at home, it’s not safe to attempt. 

These are flammable gasses, after all. People have severely hurt themselves and even blown their homes up, attempting to make DIY gas solvent hemp products. 

There’s a high potential for accidents even when professionals with industrial extraction equipment perform the process. Any residual solvent in the finished product would be a flammable gas that could contribute to health concerns if ingested or inhaled. Be wary of products created this way.

Using Supercritical CO2 to Produce Hemp Extracts

The process will start with the liquid CO2, which is at the top left corner. You will then increase the pressure of the liquid carbon dioxide using a compressor, which is located at the top middle and then uses the heater at the top right to increase the temperature.

The supercritical carbon dioxide will then be passed into some high-grade industrial hemp that’s contained in the extractor located at the bottom right corner. During this stage, the CO2 will pull out all of the essential terpenes and trichomes oils and waxes from the plant material.

The solution, which consists of the supercritical CO2 that contains all the ganja good stuff, will then be passed into a separator, which is located at the bottom middle and is then broken down into constituent parts.

The terpenes, trichomes, and some other goodies will then be sent into a collection receptacle while the supercritical CO2 will pass into a condenser before it’s turned back to a liquid. Such liquid will then be sent towards the storage tank where it will be used to start the process over again.

If you’re wondering about the residual CO2 that’s left over in the extract, then there’s really no need to worry. Lowering the pressure of the CO2 after the process of extraction is completed should be enough to allow for the liquid molecules to turn back to a gas and eventually evaporate to the atmosphere.

Perhaps, this is the simplest part of the entire process – leaving the extracts in room temperature.

This is pretty much the same reaction that triggers the soda to go flat right after you open it and once it starts to warm up. There are supercritical machines that can help simplify the process by recycling, recapturing and reusing the carbon dioxide gases that are produced after the process of extraction is completed.

Dry Ice Carbon Dioxide Extraction

The price of custom-made carbon dioxide weed oil will vary greatly. As we delve deeper on the above, the price of an industrial and state of the art supercritical carbon dioxide extraction system could run up to $39,000.

Sure, you may not have this much money to spend, and your local bank will most likely not loan you that amount of money without a business plan. Nevertheless, it’s still possible for you to make your own potent, environmentally safe, solvent-free, and concentrated CBD at the comfort of your own home even if you would rather choose not to spend a small fortune in an industrialized supercritical carbon dioxide extraction machine. However, without proper training, you could risk blowing your entire home up when you experiment with the butane methods.

Fortunately, it’s fairly common, easy, and safe to use the CO2’s solid form or the one that they call dry ice when it comes to producing your own high-grade kief hash.

This is what you will need to get started:

  • 3 lbs. dry ice
  • 3 Mason jars made of glass to be used in storing kief hash.
  • 6 oz. industrial hemp flower
  • Bubble hash mesh bags, size 220, 160, and 73.
  • Clean food grade bucket, 5-gallon capacity.
  • Heat-resistant thick gloves
  • Large mirror or Plexiglass.
  • Paint scraper, putty knife, or any laminated card used for gathering kief hash

It’s important that you follow the dry ice precautions when making your own CO2 hash:

  • Always wear your gloves when handling dry ice. Dry ice is often colder compared to regular ice and has the tendency to burn the skin similar to frostbite. You don’t want to suffer from freezer burn, right?
  • Never eat the dry ice. Having frostbite on the fingers is already bad enough. However, suffering from frostbite on the esophagus is far worse.
  • Wear safety glasses for protection. When you’re cutting or chipping, make sure you put a face shield on.
  • Avoid storing the dry ice in an airtight container. The carbon dioxide that will be released could build up causing the container to explode. It’s best to store the dry ice in a thick cooler made of Styrofoam in order to slow down the process of sublimation.

Dry Ice Hash-Making Steps

The process of producing your own ice hash at home is fun and easy to follow.

Here are the steps:

  1. Wear your gloves and put on eye protection.
  2. Select your hemp strain and chop into pieces using a marijuana grinder.

If you’re serious about altering your perceptions, go for a high THC strain. Otherwise, if you’re using it for medical benefits, then opt for a high CBD strain. The more surface you’re able to create, the better for the dry ice to extract all the beneficial goodies from the cannabis plant. Make sure not to reduce your ganja into dust. Instead, give it a few more turns through the grinder to produce small pieces.

Both the single and two chamber grinder are capable of producing the exact results you’re after. You don’t really need to use the three-chamber grinder for this since you don’t want to separate the bud and kief yet.

  1. Next, place the hemp flower into the bucket. Make sure you use the plastic bucket that’s food grade, or you could end up leaching harmful compounds in the final product.
  2. Cover with dry ice and leave for three minutes. You don’t necessarily need to fill the bucket entirely. As a matter of fact, it may be better to fill the bucket just halfway through. The extra room in your bucket will give the dry ice more room to move, making the next step incredibly easier.
  3. Place the micromesh bags in the opening of the bucket and shake the content for up to 4 minutes. As soon as the hemp gets into contact with dry ice, the trichome resins will freeze as a result of the low temperatures. Once the bucket is shaken, the dry ice will move against the plant matter, knocking the frozen trichomes off.
  4. Lift up the bucket, turn upside down over the Plexiglass or mirror and start shaking it as much as you can, extracting as much cold powdery resin into the mesh bag.
  5. Make sure you give the bucket a thorough and good shaking to displace as many resins as possible.
  6. Next, use the scraper to scoop out the kief hash and place it into the Mason jar. An ounce of the hemp should be able to produce up to 3.5 grams of kief.
  7. You should get about 0.5 grams of the high-grade stuff in a smaller micron bag and around 3 grams of the lesser grade in a large bag.
  8. Repeat the previous steps for the bubble hash bags that are sized 220 and 160 to collect varying grades of pure and solvent-free CO2 hash.
  9. Finally, it’s time to dab it, infuse it, vape it, bake into edibles, or do whatever you wish! The sky is the limit when it comes to consuming this marijuana extract.

The Final Word on CO2 Hemp Extraction

CO2 hemp extraction produces the purest hemp extract because there are no solvents involved in the process. The cannabinoids and terpenes are preserved as perfectly as possible, allowing you to enjoy the full array of benefits and effects of the hemp plant. 

Making supercritical CO2 hemp extract at home would be very expensive, so it’s mainly used by those with big operations in the cannabis industry. Dry ice hash is a great cost-effective alternative for hobby hemp growers who make their own CBD products or cannabis oils. Start from seed, grow your plant, and make your own solvent-free CBD hash.


Can CO2 and Renewable Carbon Be Primary Resources for Sustainable Fuels and Chemicals? | ACS Publications

Supercritical carbon dioxide: a solvent like no other | Beilstein Journal of Organic Chemistry

Exploding danger: U.S. marijuana oil labs pose deadly, destructive hazard | Reuters