Explore the Pros and Cons of Co2 Extraction Method vs Ethanol Extraction

What is the Best Extraction Technique: CO2 extraction method or ethanol extraction?

There are many different methods of extracting cannabidiol (CBD) or tetrahydrocannabinol (THC) and other cannabinoids from biomass. Each extraction method uses a different solvent to pull oils out of the biomass. While each method carries its pros and cons, supercritical CO2 extraction has emerged as the leader for demanding customers while driving high throughput and low operating costs, with the best quality, purity, and consistency oils produced. The following table compares the pros and cons of CO2 extraction method and ethanol extraction methods:

Table 1. Comparison of Solvent and CO2 Extraction Techniques

Parameter Ethanol Extraction Supercritical CO2 Extraction
Organic Oil Organic ethanol required.1 No special requirements, approved organic solvent.1
Cannabinoid Recovery 50-80% typical cannabinoid recovery including carbon scrubbing. Method may require carbon to remove chlorophyll. Carbon absorbs THC and CBD which lowers recovery. Carbon is a high cost consumable. 85-95% typical cannabinoid recovery. No carbon required.
Solvent Recovery Ethanol is expensive and therefore needs to be recovered.  Typically, 90-95% recovery of ethanol leads to high operating costs.  Losses come from ethanol remaining in biomass and in the extract. No need to recover CO2 other than recycling within a run or batch due to low expense of CO2.
Reuse of Extracted Biomass Biomass extracted with ethanol is hazardous waste until the ethanol is removed to negligible levels, may be flammable and/or toxic due to type of ethanol used. 2,3 Transportation is typically regulated. Biomass extracted is clean and is a source of food grade essential amino acids. Transportation is not regulated.
Winterization Winterization may be avoided if extraction is at < -20oC leading to high energy expense.  Warm ethanol extractions need to be winterized. Winterization may be avoided with subcritical extraction.  However, extraction is much slower at low pressure.
Safety Significant fire hazard risk for indoor deployment.4 Inert. No fire hazard risk.5, Static and asphyxiation risks are mitigated with proper install.
Infrastructure Cost & Requirements High cost for hazardous building occupancy and special room classifications and limitations.4,a Minimal requirements. May operate in industrial building (F2) classification.4
Equipment Cost $2-3M USD for 1 ton per day $3-4M USD for 1 ton per day
Operating Cost High variable costs and overhead due to ethanol cost, losses of ethanol, consumables, reduced recovery, high insurance premiums, hazardous waste disposal, and energy costs. Very low variable cost for CO2. No difficulty getting business insurance.
Scalability Scalable easily to 10 tons per day in less than 450 m2 with hazardous (H2,3) occupancy, with about ~7000 amps, 230V, 3 phase cooling capacity and C1D2 special rooms.6 Scalable easily to 10 tons per day in less than 450 m2 in F occupancy with ~2400 amps 230V 3 phase.
Solvent Sourced Cross Contamination Risk  Herbicide, pesticide, solvent contamination,  extraction byproduct contamination and build up risk.b CO2 is not generally used across lots.  No risk of cross contamination.
Solvent Sourced Cross Contamination Risk  Herbicide, pesticide, solvent contamination,  extraction byproduct contamination and build up risk.b CO2 is not generally used across lots.  No risk of cross contamination.
Cost of Solvents Food grade ethanol is safest and comes little to no chemical contamination risk but with higher cost. Specially denatured solvents are less expensive but carry a myriad of non-food grade contaminants.7 Low price per kg.
Terpenes for full spectrum flavor and aroma Lost during processing. Harvested during processing.
Environment High carbon footprint to produce ethanol, tons of cooling capacity needed to cool to <20oC, and dispose of hazardous biomass waste after processing. Byproduct of existing industrial processes, non toxic, non eco toxic, renewable, recaptured.8 Considered a green solvent by the American Chemical Society.
  1. Limits on the amount and storage of flammable solvents in addition to specific alarm lights and deflagration alarms and detectors, emergency phones and alarm systems with 24-hour third party monitoring, alarm levers every 150 ft, setbacks from property lines or other adjacent occupants, automatic and special sprinkler systems, fire distance offsets, deratings on maximum solvent volume for multi-story, emergency power for vents, fail safe electrical systems, spark proof venting, certified equipment for hazardous locations, and explosion control plans.4,9The use of CO2 as an extraction solvent does not require any of this infrastructure since there is no limitation on the amount of CO2 a factory can have on site.4
  2. Most importantly, ethanol derived chemical contaminants10that remain in the extracted oil after removal of the ethanol, may increase the risk of safety and health for the consumer. For example, some of the residual contaminants listed in the specially denatured ethanol recipes have a higher boiling point compared to ethanol and are not removed from the oil during distillation.  Furthermore, solvent analysis for contaminants are not always included in a typical certificate of analysis.

The table shows that in terms of every factor except capital equipment cost, CO2 extraction method has advantages over ethanol as the extraction method.  Taken collectively, CO2 extraction as a method leads to DRASTICALLY lower operating costs.

It’s All About Operating Costs

The following table shows why CO2 is such an attractive business proposition compared to ethanol technology:

Table 2. Estimated Difference in Solvent Cost for a 1 ton per day Ethanol and CO2 system.

  Ethanol CO2
Approximate Equipment Cost $2,000,000 $4,000,000
Required Solvent Start-Up Cost $7,000 $500
Solvent Loss Cost per Day $3,500 $115
1 Year Solvent Loss Cost $1,260,000 $42,048
10 Year Solvent Loss Cost $12,260,000 $340,000

    Adjust slider values in order to represent your specific business.

    1. Biomass throughput is 1 ton per day processing to distillate.
    2. All costs are approximate and in USD.
    3. Costs of infrastructure, biomass disposal, revalidation costs, and energy are neglected in the analysis.
    4. 5% ethanol lost per day at 1 gallon ethanol/lb of biomass extraction ratio.  Assume no carbon or filters are used.
    5. Cost $35/gallon for food grade ethanol.  Reduce figures to $12/gallon for denatured ethanol. Does not include shipping.
    6. Cost of CO2 in bulk delivered is about $0.04/lb.

    With the highest cannabinoid recovery levels and low operating costs, CO2 extraction is usually the best choice for your manufacturing equipment foundation to serve multiple market segments. Read our Analysis of Ethanol and CO2 Extraction Techniques.



    1. Guidance & Instructions for Accredited Certifying Agents & Certified Operations | Agricultural Marketing Service https://www.ams.usda.gov/rules-regulations/organic/handbook (accessed Dec 8, 2019).
    2. eCFR ‚ÄĒ Code of Federal Regulations- EPA Hazardous Waste https://www.ecfr.gov/cgi-bin/retrieveECFR?gp=&SID=c94567294dff611654af7a3944a91d69&mc=true&r=PART&n=pt40.28.261#sp40.28.261.c (accessed Dec 15, 2019).
    3.  Hazardous Waste from Cannabis Extraction РExtraction Magazine https://extractionmagazine.com/2019/08/14/hazardous-waste-from-cannabis-extraction/ (accessed Dec 15, 2019).
    4. Chapter 3: Use and Occupancy Classification, Building Code 2015 of Utah | UpCodes https://up.codes/viewer/utah/ibc-2015/chapter/3/use-and-occupancy-classification#3 (accessed Dec 8, 2019).
    5. CGA P-1-2015 – Standard for Safe Handling of Compressed Gases in Containers – 12th Edition https://webstore.ansi.org/standards/cga/cga2015-1531002?gclid=CjwKCAiA27LvBRB0EiwAPc8XWflJxH6MAC74YxV5upUoi5lt6OakcaPK5L_mu7CrSSu5CMXTjcG9mxoCrikQAvD_BwE (accessed Dec 8, 2019).
    6. 2006 International Building Code https://www.optasoft.com/applications/codes/2006IBC/HTMLHelp/414.htm (accessed Dec 8, 2019).
    7. ¬†eCFR ‚ÄĒ Code of Federal Regulations- TTB Alcohol and Rules for Specially Denatured Alcohol https://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&sid=fc3be5d2e97afdd4aed5fb7b5c26309c&rgn=div5&view=text&node=27: (accessed Dec 8, 2019).
    8. Brunner, G. Applications of Supercritical Fluids.¬†Annu. Rev. Chem. Biomol. Eng.¬†2010,¬†1¬†(1), 321‚Äď342. https://doi.org/10.1146/annurev-chembioeng-073009-101311.
    9. Chapter 9: Fire Protection Systems, Building Code 2015 of Utah | UpCodes https://up.codes/viewer/utah/ibc-2015/chapter/9/fire-protection-systems#903 (accessed Dec 8, 2019).
    10. eCFR ‚ÄĒ Code of Federal Regulations https://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&sid=3f34f4c22f9aa8e6d9864cc2683cea02&tpl=/ecfrbrowse/Title07/7cfr205_main_02.tpl (accessed Dec 8, 2019).

    Frequently Asked Questions

    Why should I choose extraktLAB equipment?

    extraktLAB’s supercritical CO2 extractors are highly efficient and increase overall extraction yield. They are also capable of decreasing your yearly operating costs and leave scale up opportunities.

    Does hemp biomass need to cure before extraction?

    No, the material does not need to cure. Our methods complete the final drying step in a vacuum oven to bring the water content down from 10% to the 1% – 1.5% range for efficient CO2 extraction.

    Can the drying process be accelerated using higher temps/lower humidity?

    There are several drying methods used by growers to accelerate drying, but this is outside our scope of solutions. We recommend researching the agricultural methods to find what works best for you.

    What are the typical conditions to dry hemp for extraction?

    Harvest drying methods are outside the scope of our solutions; however, you want to dry the biomass to roughly 10% water content for quality storage to prevent mold or mildew.

    When producing CBD from hemp, which part of the plant is typically used?

    Typically flowers and leaves – no stems or stalks. Some producers will sort out the flowers and process them separately, but most processing includes the leaves and flowers.

    Can ethanol become contaminated during ethanol extraction?

    Yes, ethanol can become contaminated during ethanol extraction. It is important that you address the contamination with testing and reuse protocols. guidance for solvent reviews have been published by the FDA in 2010. Please refer to the many articles in this blog for more information on cross-contamination with extraction.

    What is the electrical cost of ethanol extraction vs. CO2 extraction?

    Processing a ton of hemp per day into extracts  can be an energy-intensive process depending on how the hemp is extracted. The following table compares the energy expense for ethanol extraction versus the energy expense for CO2 extraction:

    Energy cost for Ethanol Extraction for 1 ton per day at 1 gallon ethanol per 1 lb of hemp
    18711 litres to cool from 25 to -20
    16840 litres to heat and evaporate after ethanol loss
    454 kwhr to Cool from 25 to -20
    481 kwhr to heat to boiling point
    3105 kwhr to evaporate
    4040 kwhr total @ 100% Efficiency
    75% Efficiency
    5387 kwhr Total
    $           0.09 per kwhr
    $          506.36 per day


    Energy cost for CO2 Extraction at 1 ton per day including winterization
    636 litres to cool from 25 to -20
    636 litres to heat and evaporate after ethanol loss
    15 kwhr to Cool from 25 to -20
    18 kwhr to heat to boiling point
    117 kwhr to evaporate
    151 kwhr total @ 100% Efficiency
    75% Efficiency
    201 kwhr Total
    $           0.09 per kwhr
    $        18.92 per day for winterization
    43.20 Kwhr per day for CO2 extractors
    $         3.88 Per day for CO2 extractors

    Would you recommend ethanol extracted oils for Vape products?

    Due to the risk of chemical contaminants that are found in 25 to 30% of  ethanol extracted oils, we recommend that CO2 oils be used for Vapor Products.

    Is it possible to make a solventless extract with CO2?

    It is absolutely possible to make a solventless extract with CO2. Solventless extracts are typically made with subcritical CO2 extraction methods.

    Does ethanol extraction have a greater throughput than CO2 extraction?

    Hemp processing equipment can be scaled for 1 to 5 tons of extracted hemp per day. It’s generally not a fair comparison to compare the throughput on an instrument from two different companies. What is fair is to specify the throughput At the tonnage process per day and then look at the operating cost for that process. You can also look at the equipment and Facilities cost to accommodate that level of Production. after you have all of your costs accounted for including the hidden costs, then you can calculate the net present value for each investment.

    What are the most common denaturants in ethanol?

    Denatured ethanol is a mixture of denaturants and pure ethanol. Chemical companies add the denaturant to Pure ethanol so that they will not be consumed as a food.
    Denatured recipes are published by the ttb that is administered by the National Bureau of Alcohol Tobacco and Firearms. There are many different recipes. one of the most common denaturants used in ethanol extraction is heptane. However there are other substances that may be used including acetone, isopropyl alcohol, methanol and other longer chain alcohols.
    Is very limited data on the safety of heptane over the long term exposure. In fact the limit that the FDA has placed on the amount of heptane in a tincture for example was established in the 1990s on the basis of a single study published in 1981. That study the effect of heptane on Sprague dawley rats. That is why there are many disclaimers and the general guidance from the FDA is to limit the amount of solvent in any drug that is consumed.

    Doesn’t ethanol extraction equipment remove all the ethanol from the biomass after extraction?

    No. Approximately 5 to 10% of the ethanol is left in the biomass and is counted as a solvent loss. These solvent losses add up to operating costs. This is especially true if organic ethanol is used or food grade ethanol is utilized as the extraction solvent.

    If you had an ethanol extraction facility, would you ever use CO2 just for stripping terpenes?

    Ethanol extraction typically destroys the terpenes when the ethanol is removed from the extract or is distilled from the winterized oil. Many ethanol extractors are seeking a way to preserve the terpene profile of the plant in the output oil. To this end people have tried techniques such as Steam distillation, CO2 stripping, and vacuum distillation.
    Certainly, CO2 can be used to strip terpenes from Hemp biomass Prior to ethanol extraction. However, vacuum distillation is by far the most gentle and effective way to harvest the terpene profile prior to ethanol extraction.

    How do I model and compare the financial return of ethanol extraction vs CO2 extraction?

    There are many inputs that need to be defined when creating a financial model comparing two different extraction methods. The first decision to be made is to decide what the financial metric will be used to make a decision on the superiority of one method over the other. 

    In this case, we recommend the use of the Net Present Value as the way to model the return of each extraction technique because it accounts for the cash flow associated with the operation. Many ethanol extraction companies try to make the argument that ethanol extraction is lower cost because the equipment cost is less. However, the equipment cost will have very little impact on the overall profitability of the operation at the same throughput.

    The best way to compare the two techniques is to fix the throughput so that an apples-to-apples comparison can be made. Comparisons such are payback time and return on investment can mislead someone into making a bad investment decision. 

    So if we fix the throughput at one ton per day the cost of the hemp is equal between the techniques and operating cost variance is the only contributing factor.     

    Here are the twelve key questions that need to be defined in order to do a comparison:

    1. What is the direct labor to process?
    2. What is the energy to process?
    3. What are the solvent losses? 
    4. What are the direct material startup costs including solvent startup costs?
    5. What are the cannabinoid recovery rates?
    6. How much solvent do I use, reuse, and when do I need to replace the solvent with fresh solvent?  and at what interval?
    7. What is the insurance cost for each option?
    8. What is the cost of hazardous waste disposal?
    9. What is the cost of solvent removal?
    10.  What is the cost of reuse of the solvent?
    11.  What is the cost of HAP emissions?
    12. What is the depreciation for each option including building costs for H2 vs F2 occupancy?

    Once these questions are answered you will be able to build a pro forma income statement. 


    • Standard labor
    • Standard materials
    • Overhead

    Gross margin

    • SGA
    • R&D

    Net Margin

    You can then hold SG&A and R&D constant for both techniques and account for the difference in depreciation to get to a net margin number.  

    A cash flow statement can then be generated from net margin. One thing to note is that depreciation must be added back to net margin as it is a non-cash expense on the income statement.  

    Cash flows are then added up for 5 consecutive periods (years) including the initial outlay of cash for startup working capital.  Those cash flows are then discounted at a discount rate (Weighted average cost of capital estimate at 13-17%).  

    If you do this analysis, you will find that CO2 extraction will absolutely crush ethanol extraction in terms of net present value.  

    Does it cost less to process hemp with Co2 compared with Ethanol?

    In fact the operating cost for CO2 extraction is dramatically less than the operating costs associated with ethanol.

    Extraction with Ethanol is a process that is typically run at low temperatures. First the ethanol is cooled to below -20oC before it is introduced to the hemp. Cooling the ethanol reduces the amount of extracted chlorophyll and waxes. If you account for the energy required to chill the ethanol down to those low temperatures and then also evaporate after use, the energy bill for extracting ethanol is approximately 3-6x the cost of extracting with CO2. However, the energy cost is really not the key driver in the overall operating costs.
    Ethanol extraction requires a significant amount of ethanol to be used per pound of hemp. In fact, about 1 to 1.5 gallons of ethanol must be used per pound of dry hemp in order to extract. Hemp is a very absorbent biomass material and the ethanol must fully saturate the hemp plant before any extraction can take place. For this reason a large volume of ethanol is needed to extract cbd from hemp.
    The key cost driver or ethanol extraction is recovery of that solvent from the biomass. Even though many ethanol extraction equipment companies provide centrifuges and or presses to eliminate the amount of ethanol left over in the biomass, The best equipment will provide only a 90 to 95% recovery of the ethanol. This 5 to 10% loss in ethanol is a huge cost driver for extracting ethanol.
    For example, suppose you wanted to process 1000 lb of hemp. You would need 1000 gallons of ethanol to start out at a cost of $16-33 per gallon for food grade ethanol for a total cost of $16,000 to $33,000. If you recovered 90% of the ethanol the ethanol loss would be $1,600 – $3,300 per 1000 lbs. Furthermore if you process 1000 pounds per day, this would be your daily loss.
    In contrast, you will lose the equivalent of about $70 per day for CO2 extractions for the exact same process.
    Besides energy and solvent usage, there are many other hidden costs related to extraction with ethanol including solvent reuse costs, insurance cost, increased facilities cost, and testing costs.

    Is CO2 cheaper than ethanol?

    A pound of food grade ethanol when purchased in bulk is $4.71/lb at current price.
    A pound of food grade CO2 when purchased in bulk is about $0.04/lb at current price.

    What’s the purity of the CO2 used in CO2 extraction?

    There are many grades of CO2 including industrial and food grade and medical grade. We typically use food grade but medical grade is also highly desirable. the specifications for each of these grades are published by the Compressed Gas Association or by your gas supplier.