Terpene Extraction Methods: Weighing Up the Pros and Cons

In this article we will discuss about terpene extraction. The methods of extracting terpenes are aplenty. Each technique can produce high-quality terpenes and has specific advantages and disadvantages.  

Since extraction affects the final product’s potency and concentration, it plays a vital role in the resulting quality of the terpene. In this article, we will discuss the different extraction methods, as well as what they bring to the table, to help enthusiasts better understand the terpene extraction process.

6 Common Terpene Extraction Methods: Pros and Cons

Terpene manufacturers worldwide may use any of these extraction methods. 

1. Steam Distillation

The steam distillation process involves placing the plant over boiling water. This exposure to heat causes the release of terpene molecules into the air. A pipe then collects the vapor and channels it into a chamber where it condenses. Once it turns into liquid, the oil floats to the water’s surface, ready to be collected.

Steam Distillation Pros

  • It is efficient – Unlike other methods, the steam distillation process can generally extract all the terpenes in a single round with a single distillation chamber. 
  • It can easily be scaled into a larger operation – Given how relatively simple the process is, steam distillation can be scaled into a larger industrial operation with ease.
  • It produces pure terpenes – Since the process does not use any solvents, it preserves the natural terpenes in the product while reducing the chances of contamination. 

Steam Distillation Cons

  • It may not work for all plants – Since the specimens will be exposed to high temperatures, not all plants may be able to handle such a range, especially delicate ones. 
  • Aromatics loss – Due to the high temperature, there can be degradation of certain fragile molecules and terpenes. Some of the terpenes can also be lost in the water fraction.
  • Operators need prior training – Although the process is simple, it requires training in operating the equipment, which includes handling condensers, hot plates, and flasks. Unskilled individuals may easily contaminate the terpenes and reduce their quality. 
  • It may entail high operational costs due to equipment – The equipment needed may be costly. Additionally, the process requires high energy usage, contributing to the overall operational cost.    

2. Hydrodistillation

Hydrodistillation is very similar to steam distillation. In fact, steam distillation can be considered a form of hydrodistillation. 

Here, the flower is soaked in boiling water. A condensing apparatus collects the vapor produced, which is directed to a receiving flask. The moisture and oil are then separated, making it easier for the oil to be collected. 

Hydrodistillation Pros

  • The process is relatively simple Ancient civilizations have used this method to produce essential oils for different purposes, such as aromatherapy. The simplicity of the process is one reason this method is highly favored. 
  • It uses simple tools – The equipment needed to perform the process is quite simple and does not generally require prior training.
  • It preserves the quality of the oil – Like steam distillation, the process doesn’t use solvents, retaining the natural terpenes in the final product. 

Hydrodistillation Cons

  • The process tends to consume high amounts of energy — Given that the temperature needs to be carefully controlled, a high amount of energy may be required to extract the oils effectively. 
  • The long collection period may slow down the process – The oil molecules in the terpenes need time to break down and vaporize. If the extraction involves a large number of plants, the process may take longer to be completed. 
  • The quality of the terpenes may be reduced – Since the plant is soaked in boiling water, the quality and potency of the terpenes may be reduced. Terpenes are susceptible to temperature changes, so subjecting them to high temperatures may affect their final profile. 

3. Hydrocarbon Extraction

Terpene manufacturers use hydrocarbon extraction to collect not only terpenes from plants but other cannabinoids as well.

This method uses solvents like butane and propane to draw out the terpenes from the plant. The extract undergoes multiple rounds of purging to eliminate any residual solvent. The final refining stage includes a filtering procedure to remove fats, lipids, and other cannabinoids from the concentrate.

Hydrocarbon Extraction Pros

  • It can preserve the terpene’s potency – This method can preserve the unique chemical composition of each terpene strain, maintaining the original profile in the final product.
  • More terpenes can be extracted – Once the equipment is set up, it is easy to perform the process. The automated setup produces more terpenes with minimal post-processing.
  • It is versatile – This method can produce various terpene products, including live resin, shatter, wax, and distillate. 

Hydrocarbon Extraction Cons

  • The final product may not always be safe – Extractions performed by untrained individuals may result in products containing toxic solvents, but a good operator will not have any issue with this.
  • The process may pose risks – Butane and propane are highly flammable and can cause severe injuries or even death if mishandled. 
  • Hydrocarbons are strictly regulated – Facilities operating with hydrocarbons are highly regulated by authorities. This can make it challenging to scale up terpene extraction legally.

4. CO2 Extraction

CO2 extraction uses carbon dioxide to extract the terpenes. Here, carbon dioxide is first placed in a cool chamber. It is then pressurized to convert it into its supercritical state.

Next, the supercritical carbon dioxide is diffused into another chamber containing the plant. The carbon dioxide then absorbs the terpenes and separates them into a third chamber where they can be collected.

CO2 Extraction Pros

  • The process is highly flexible – Operators have complete control over the procedure. They can adjust the pressure and temperature according to their desired product.
  • It’s safe for the environment – Since carbon dioxide is recyclable, the process leaves a minimal environmental footprint.  
  • CO2 is safe to use – Supercritical carbon dioxide is recognized by the Food and Drug Administration (FDA) as safe for industrial use. It is non-toxic and can kill molds and bacteria during the entire process. 
  • Great results – The finished terpene product of CO2 extraction can be very high quality with great results.

CO2 Extraction Cons

  • It can be costly – Supercritical carbon dioxide is not easily obtained and requires a higher upfront cost than other extraction methods. 
  • The method may take longer to be completed – Batches tend to fluctuate in temperature and pressure, increasing the amount of time it takes to complete the process. For instance, extracting oil from a 20-pound plant may take up to six hours. 
  • The method requires advanced training – Since the method is quite complex, operators need to undergo training before using the equipment to avoid inaccuracies in the production process.

5. Hexane Extraction

This method uses the chemical solvent, hexane, to extract terpenes from the plant. Hexane is first mixed with the crushed plant. Once hexane has drawn out the oil from the plant, the mixture is vaporized using steam or heat. 

The vapor is collected in a flask where more heat is introduced. At this point, the hexane is evaporated, leaving only the terpene compounds. The vapor is then condensed back to its liquid form and directed to a flask where the oil can easily be collected. 

Hexane Extraction Pros

  • It enables a faster extraction process – Water evaporates at the rate of 0.3, which is considered slow. Hexane evaporates quickly at the rate of 8.3
  • It preserves the terpenes in the concentrate – Once hexane is evaporated, it leaves behind only the essential terpenes. Given that it evaporates quickly, it helps make the process more efficient.
  • The process is economical – The condensation process ensures that hexane does not leave the extraction system and that it is reused.

Hexane Extraction Cons

  • The process may take longer – The entire process may take several hours or days to complete, which can prolong the production. 
  • Product consistency may vary – If the mixtures are not properly diluted, they can produce inconsistent and lower-grade terpenes. 
  • Hexane can be dangerous if mishandled – Hexane is highly flammable, so operators must be trained to use it. 
  • Residual solvent – Due to the higher boiling point of hexane, it is harder to get the hexane out of the extracted terpenes.  

6. Ethanol Extraction

This process involves soaking the plant in 95% to 100% ethanol solution. Once the ethanol extracts the oil, the solution is placed in a heated container to evaporate the ethanol. The remaining oil is then collected in a separate chamber. 

Ethanol Extraction Pros

  • It can produce highly concentrated products – Depending on the efficiency of the extraction process, the oils produced can potentially achieve 80% to 99% concentration with minimal residual chemicals. 
  • It is cost-efficient – Since ethanol is inexpensive, businesses can scale their extraction operations and expand their production.
  • Ethanol is safe – Ethanol is non-toxic and is recommended by the FDA for industrial use.

Ethanol Extraction Cons

  • Ethanol can be dangerous if not handled well – Ethanol is highly flammable, requiring great caution in using it, especially during the heating processes. 
  • The process may take time – Since ethanol has a high boiling point of around 78°C, the process can be a lengthy one. 
  • The product needs to be extensively refined – The chlorophyll content of ethanol can be retained in the final product, leaving it with a bitter taste if not adequately refined. 
  • Residual solvent – Due to the higher boiling point of ethanol, it is harder to get the solvent out of the extracted terpenes.  

Excellent Extractions Lead to Excellent Terpenes

One important factor that affects a terpene’s quality is the extraction process used to produce it. With the different methods used to extract terpenes, it’s vital to know the benefits and disadvantages of a particular method. 

When buying terpenes or creating a custom terpene profile, stick to verified and authentic terpene manufacturers for the safest and best-quality terpenes. At Medical Terpenes, we use the finest extraction methods to produce high-quality terpene products.

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