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How to Retain Terpenes by Carbon Dioxide Extraction?

What are Terpene Oils?

Plants rely on terpenes for signaling purposes, whether to ward off would-be predators or attract pollinators like bees and butterflies. These aromatic compounds that plants produce naturally give each plant its unique scent and flavor and help them communicate with other living things.

Any single plant would have numerous terpenes, and terpene structure varies. The combination of various terpenes creates the distinct aroma of any plant. It means that most aromatic plants and herbs have multiple types of terpenes and the unique fragrance results from a unique combination.  Besides CBD and THC, terpene oils are another valuable component in cannabis, that until recently, hasn’t received as much attention.

There are over 100 different terpenes that create the distinct flavors found in cannabis varieties, including citrus, pine, and berry. These aromatic oils contribute flavors and aromas that cannabis connoisseurs enjoy, but their potential goes far beyond. Terpene oils provide increased relaxation, lower stress levels, promote clarity, and reduce chronic pain, among other therapeutic and medicinal uses.

Terpene oils and cannabinoids combine to have a synergistic impact on the human body. The resulting “entourage effect” creates more overall benefits than just one compound can when used independently.

How to extract Terpene Oils?

There is one major issue with safely separating terpenes from a crude oil extract. They are delicate and prone to degradation, so their molecular structure can be altered by heat before extraction even begins.

Solvent-Based Terpene Extraction

Terpenes are sensitive to heat and pressure, and either can ruin the oils’ aroma, flavors, or chemical structure. Their molecular structure is altered with even moderate heat or pressure stress. That’s why terpenes must be extracted gently at a very low temperature in a manner that will render the resulting product unadulterated.

Using a light hydrocarbon to extract oil with a high terpene profile, specifically butane or propane or a propane-dominant blend. Harvesting the plant when terpene content is at its peak and extracting it with light hydrocarbons results in a soupy mixture that can then be lightly heated to remove the solvent; the required temperature isn’t high enough to degrade the terpenes. A centrifuge can then remove the terpenes and separate them from the cannabinoids, resulting in a purified terpene compound.

Extracting Terpenes with CO2

Using supercritical CO2 is one of the most common methods of CBD extraction. Supercritical CO2 is an excellent solvent. It is formed by compressing CO2 at high pressures and still maintaining a high temperature. However, this method poses some challenges in extracting terpenes. Terpenes do not like the high temperature of supercritical CO2. Terpenes are highly volatile.

It means that using supercritical CO2 alone would not help get products rich in terpenes. Although that may not be a problem when the aim is to produce pure CBD isolate. However, extracting terpenes make commercial sense as these incredible aromatic compounds are costly.

Process of Terpene Extraction

Fortunately, it is known that these terpenes dissolve well into ethanol. Therefore, one way is to introduce 5% ethanol to CO2 extraction. This can be combined with so-called decarboxylation, a process of converting acidic cannabis to a neutral form, which considerably improves the extraction of cannabinoids and terpenes. Thus, it is good to decarboxylate before making oil.

Using a small amount of ethanol is a very economical way of terpenes extraction. In addition, it does not add up much to the total extraction costs. However, ethanol is not a perfect method, as it has numerous limitations.

The end product of ethanol extraction is dark-colored biomass that is abundant in terpenes. However, this biomass still contains ethanol along with fats, waxes, and other cellular materials. Therefore, it means that this biomass still needs further processing for extracting terpenes.

Can terpenes be destroyed during the extraction?

In short, the answer is yes. Not all, but partial degradation of terpenes occurs when ethanol is used to extract terpenes. This degradation and even loss of terpenes occur during the distillation process.

Biomass produced through ethanol extraction is not very pleasant. One still needs to use evaporators to remove ethanol and other impurities. However, this process has some problems. Terpenes are highly volatile. It means that many terpenes evaporate along with ethanol, resulting in considerable loss.

But that it’s not all. Applying heat also degrades many terpenes. Nonetheless, after evaporation, dark-colored oil rich in terpenes is left behind. These remaining oils must be further processed to get pure and safe to consume terpenes.

So, as one can see that although ethanol is an excellent way of terpenes extraction, like any method, it has its downsides. Prolonged application of heat during evaporation degrades terpenes. Due to a similar boiling point, many terpenes are lost during the evaporation process.

CO2 as a solvent for terpene extraction

Using supercritical CO2 is one of the most common methods of CBD extraction. Supercritical CO2 is an excellent solvent. It is formed by compressing CO2 at high pressures and still maintaining a high temperature. However, this method poses some challenges in extracting terpenes. Terpenes do not like the high temperature of supercritical CO2. Terpenes are highly volatile.

It means that using supercritical CO2 alone would not help get products rich in terpenes. Although that may not be a problem when the aim is to produce pure CBD isolate. However, extracting terpenes make commercial sense as these incredible aromatic compounds are costly.

Process of Terpene Extraction

Fortunately, it is known that these terpenes dissolve well into ethanol. Therefore, one way is to introduce 5% ethanol to CO2 extraction. This can be combined with so-called decarboxylation, a process of converting acidic cannabis to a neutral form, which considerably improves the extraction of cannabinoids and terpenes. Thus, it is good to decarboxylate before making oil.

Using a small amount of ethanol is a very economical way of terpenes extraction. In addition, it does not add up much to the total extraction costs. However, ethanol is not a perfect method, as it has numerous limitations.

The end product of ethanol extraction is dark-colored biomass that is abundant in terpenes. However, this biomass still contains ethanol along with fats, waxes, and other cellular materials. Therefore, it means that this biomass still needs further processing for extracting terpenes.

Can terpenes be destroyed during the extraction?

In short, the answer is yes. Not all, but partial degradation of terpenes occurs when ethanol is used to extract terpenes. This degradation and even loss of terpenes occur during the distillation process.

Biomass produced through ethanol extraction is not very pleasant. One still needs to use evaporators to remove ethanol and other impurities. However, this process has some problems. Terpenes are highly volatile. It means that many terpenes evaporate along with ethanol, resulting in considerable loss.

But that it’s not all. Applying heat also degrades many terpenes. Nonetheless, after evaporation, dark-colored oil rich in terpenes is left behind. These remaining oils must be further processed to get pure and safe to consume terpenes.

So, as one can see that although ethanol is an excellent way of terpenes extraction, like any method, it has its downsides. Prolonged application of heat during evaporation degrades terpenes. Due to a similar boiling point, many terpenes are lost during the evaporation process.

Using sub-critical CO2 run before using supercritical CO2 to extract cannabinoids.

Preserving and maximizing terpenes

Sub-critical CO2 extraction is very similar to supercritical. However, it applies less pressure and uses lower temperatures. As a result, it is especially effective in preserving highly volatile compounds found in various herbs like terpenes in cannabis.

It yields a product that is rich in terpenes and various cannabinoids. However, it generally produces less yield than supercritical CO2 extraction and is also a slower process.

One can run the remaining plant biomass through an additional cycle of supercritical extraction to extract a greater number of cannabinoids. Supercritical extraction is also better in retaining denser molecules like fatty acids.

Thus, as one can see that there is no ideal way of extracting various phytocompounds. Each phytocompound differs in physical properties. Some are better extracted using liquid solvents like ethanol, others supercritical CO2.

Due to an increased understanding of various health benefits associated with terpenes and the importance of the entourage effect, many are using sub-critical extraction these days.

Fortunately, one can use the same equipment to carry out all these processes in automatic or semi-automatic mode. Most supercritical CO2 extraction equipment would allow the use of sub-critical CO2 extraction. Moreover, many such types of equipment also allow adding ethanol.

The truth is that no method is perfect. However, combining multiple ways of extraction, running the cannabis mass through multiple cycles is the only way to extract a maximum number of compounds. Further, lots would also depend on post-processing. Thus, the final product produced by any machine also depends on the knowledge base of any organization, its experience in producing herbal extracts.

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