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Cold Pressing vs Ethanol Extraction: All You Need To Know

Discover all you need to know about the most popular hemp extraction methods.
August 10, 2022
Company News

Discover all your need to know about cannabinoid extraction methods including Cold Pressed Hemp Oil

Until recently, most talk surrounding cannabinoid extraction methods has largely focused on CO2 extraction and solvent/ethanol extraction: which is safer, which is cleaner, which is more cost-effective and which produces a superior CBD product. But recently there’s been a new (or rather, very, very old) extraction method that’s garnered interest from CBD brands –particularly those selling products in the U.K. under strict FSA, Novel Food guidelines. That method is cold pressing.

In this article, we’re going to explore the lot and, furthermore, we’re going to take you through the pros and cons of cold pressing your cannabis to help you make an informed choice about what will work best for your company. This is something that is incredibly important, as the extraction method you use will determine both the quality and potency of your end products.

 

What is solvent extraction?

Solvent extraction is a process whereby cannabinoids, such as CBD and THC, and cannabidiolic acids, such as CBDa, are separated from plant matter. These separated cannabinoids can then be used to make CBD oil. Commonly used solvents include ethanol and butane. CO2 extraction is often referred toas a different process, but this is solvent extraction too, using a‘ super critical fluid’.

To make a CBD oil that is high in cannabinoids, the cannabis or hemp matter must be processed. The plant mass is first saturated with the chosen solvent, which binds to the cannabinoids so they can then be isolated and have the solvent removed leaving behind the concentrated cannabinoids.

 

What is Ethanol extraction?

Using Ethanol as your chosen solvent for cannabinoid extraction delivers what’s known as a ‘single stream process’ that can be conducted under warm or cold conditions. This provides a way of extracting cannabinoids and terpenes efficiently and safely. Ethanol’s relatively low boiling point also makes this solvent easy to remove from the final product without causing too much damage to the volatile compounds you hope to be left with. Both the FDA and EU deem this method to offer a favourable toxicological profile, meaning (when done right) it does not pose harm to human health.

Ethanol extraction, which has been used for thousands of years, is generally a very fast, efficient method and can be a great choice for anyone wanting to create high volumes of cannabinoid extract on a tight deadline. It also can dissolve both polar, hydrophilic, and nonpolar(hydrophobic/lipophilic) substances.

However, without going through a filtering step excess chlorophyll can be left in with the cannabinoids when using Ethanol, which might not be ideal for use in an end product as it leaves behind a dark colour and strong flavour. Shortening extraction time or using cold Ethanol can help to reduce the number of undesirable extracts, such as chlorophyll, pigments, and waxes, dissolved into the solution.

 

What is CO2 extraction?

CO2 extraction works in much the same way as Ethanol extraction, using high pressure and low-temperature to separate and preserve cannabinoid-rich oil.

The main differences between these two solvents is that CO2 has a lower carbon footprint, is considered by many experts to be less toxic than Ethanol, it’s non-flammable and has a higher cannabinoid recovery rate (85-95% as opposed to 50-80%).

However, there are some drawbacks. CO2 extraction is a lot slower than Ethanol extraction, requires more post-processing and is more expensive.

How does solvent get removed from Cannabinoids?

Heat and vacuum are used to remove solvent from cannabinoids through evaporation, most commonly by using a machine called a rotary evaporator. At True North Labs, we use a large-scale, stainless-steel version usually referred to as "Falling film" or "Rising film" style evaporators.

 

Temperature control is key to removing solvent without damaging the valuable cannabinoids you’ve worked so hard to isolate.  

 

For more on extraction methods and to gain a full understanding of what is involved, it’s worth taking a look at the recently updated paper Techniques for Extraction of Bioactive Compounds from Medicinal Cannabis extraction’. Our team are also very happy to take you through it all. Or you can take a look at TNL’s Glossary of Cannabis Extraction Terms in the appendix below.

What is Cold Pressed Hemp Oil?

Cold pressed hemp oil has risen in popularity recently to‘ get around’ the new Novel Food regulations in the U.K. Although the FSA has said that cold-pressed CBD oil is still considered a Novel Food, plenty of people believe this point could be argued, as this is a traditional method of extraction that has been used for an extremely long time. The first known uses of concentrated cannabis can be dated back to 10,000 B.C. in the Steppe Mountains of China and it’s likely that this process was used even back then.

 

Cold press extraction uses a physical method rather than a chemical approach. First, a machine applies intense pressure to the whole cannabis or hemp plant and seeds to release the oil-containing cannabinoids. Next, any sediments or residue is removed using filtration. During the process, the product is kept at lower temperatures.

 

When using cold press extraction, cannabinoids are not isolated; the cannabis product is simply separated out into liquid oil and solid plant matter – a process that is far less selective in terms of what makes it into the product and what doesn’t. Cold pressed oils are also often rich in essential fatty acids, including Omega-3 and 6. Producing a resin/oil that contains all parts of the plant, almost just as it grew but in a new liquid form, appeals to some.

 

One very important point to note with cold pressed hemp oil is that they are often raw, which means the final product will contain non-decarboxylated cannabinoids so that most constituents will be the acidic precursor versions, such as CBDA, rather than CBD. To transform cold pressed hemp oil into CBD oil,it will need further processing.  

 

However, you may not want to turn your product into a CBD oil! Although CBD oil has risen to fame in recent years, that doesn’t mean it’s necessarily ‘better’ than raw oil. Cannabidiolic acids are amazing in their own right. In fact, one study found CBDa to be 1000 times more effective at combating nausea and anxiety than CBD! Cannabidiolic acids are also water soluble, rather than fat soluble, which means they can have vastly superior bioavailability and a faster onset.

To develop the best possible cannabinoid product range for your brand and meet dramatically differing regulations worldwide, it’s a good idea to remain flexible, with a focus on using quality ingredients and processes that work. Here at True North Labs, we're problem-solvers. So whatever your preferred method of extraction is, we are here to help and get into the nitty-gritty to solve the unsolvable. If you need to use Cold-Pressed oil, or want to learn more about solvent extractions, call us! We’ll help you develop your dream marketplace-ready product, whatever challenges you may be facing.

APPENDIX: Glossary of Terms for Cannabis Extraction

Butane is an organic compound, an alkane with four carbon atoms (C4); Butane is a gas at standard temperature and pressure (STP). The term may refer to either of the two structural isomers, n-butane or isobutane or a mixture of these isomers.  — Butane
•Butane extraction, sometimes referred to as butane hash oil (BHO extraction), is a method of extracting valuable compounds from the cannabis plant using butane, a highly flammable gas. — Butane Extraction
•The total content of cannabinoids within a product. A cannabinoid is any chemical that acts on the Endocannabinoid system (ECS). Cannabinoids can be Plant-derived, known as phytocannabinoids, which are typically derived from the Cannabis (marijuana) plant. Endogenous, known as endocannabinoids and Synthetic (cannabinoids produced in a laboratory to mimic the effects of phyto- or endocannabinoids in the ECS). Most cannabinoids are lipid molecules that act as neurotransmitters in the ECS. — Cannabinoid Content
•Over 480 cannabinoid compounds have been identified within the cannabis plant. Extracts are these compounds isolated from less desirable - Cannabis Extracts
•Cannabidiol (CBD) is one of many 'active' cannabinoid molecules produced by the cannabis or hemp plant and is a significant cannabinoid along with THC.  CBD, or cannabidiol, was first isolated in the 1940s from Cannabis hemp oil. It is the most abundant naturally occurring cannabinoid in hemp and an important constituent of Cannabis — CBD
•Cannabigerol (CBG), often referred to as the mother of all cannabinoids, is one of many minor cannabinoids (makes up a small percentage) molecules produced by cannabis or hemp plant. — CBG
•Cannabinol (CBN) is another minor cannabinoid-derived plant compound, but it does not originate from cannabigerol but comes from the breakdown of THC. When THC is exposed to light and heat (aka oxidation), it turns into a unique metabolite: CBN. Unlike THC, however, CBN does not have psychoactive effects — CBN
•A green pigment in all green plants absorbs light energy to power food production. It is considered an undesirable compound and should be avoided or removed during extraction. — Chlorophyll
•Column chromatography is a technique used to isolate a single chemical compound from a mixture. The column is packed with a stationary phase, where a mobile phase dissolved mixture flows and separates. — Column Chromatography
•The oleoresin removed from the plant contains essential oils and cannabinoids (including THC). Crude is usually further processed into a more pure form. — Crude
• Freezing temperatures. For cannabis extraction, "cryo" is any temperature lower than the standard -40 point where Celsius and Fahrenheit are the same. — Cryogenic Temperatures
•A solid phase organization of atoms or molecules into a highly structured macroscopic form called a crystal. — Crystallization
•Also known as D.E, diatomite or kieselgur- is a soft, siliceous sedimentary rock that is easily crumbled into a fine white or 'off-white' powder. It has a particle size ranging from less than 3 microns to more than 1 mm but is typically 10 to 200 microns. It is often used in chemistry as a filtration aid to filter fine particles that would otherwise pass through or clog filter paper. — Diatomaceous Earth
•In cannabis resin, degumming is the process of removing lecithin-type compounds (phosphatides). Degumming of vegetable oil, also called water refining, treats the oil with a small amount of water and additives, followed by centrifugal separation and/or filtration. — Degumming
•A chemical reaction that removes a carboxylic group and releases carbon dioxide. In cannabis, decarboxylation refers to the reaction of the natural cannabinoid-carboxylic acid (e.g. THCa, CBDa) using heat to produce simple cannabinoids (e.g. THC, CBD) CO2 gas.— Decarboxylation
•Cannabinoid distillates are a cannabis resin product made by various distillation methods to contain between 85% to 99% active cannabinoids. — Distillate
•A synergistic effect between cannabis compounds that magnify the therapeutic benefits of the plant's components. A well-designed lab also has an entourage effect. — Entourage Effect
•Enzyme-assisted extraction technique (EAE) has also been utilized to extract oil from Cannabis. Enzymes are applied during the extraction process to release phytochemicals from the plant cells Enzyme-Assisted Extraction
•Because of its relatively low toxicity and boiling point compared with other alcohols and its ability to dissolve non-polar substances, ethanol has a wide range of applications. — Ethanol
•Favored by extractors and regulators alike, ethanol is effective, efficient, and safe to handle. Compared to the other two primary extraction methods, ethanol is as safe as CO2 but as efficient as butane. — Ethanol Extraction
•The flash point of hazardous material is the lowest temperature at which a liquid will form a vapour in the air close to its surface which will ignite when given an ignition source and oxidizer, such as oxygen. — Flashpoint
•Diverse phytonutrients (plant chemicals) are found in almost all fruits and vegetables. In cannabis, flavonoids contribute to the colour, taste, smell, entourage effect and overall sensory experience. — Flavonoids
•Separation a mixture into parts or fractions according to their boiling points. Compounds (chemical) are separated by heating them to a specific temperature (often under vacuum) at which one or more of the fractions of the mixture will vaporize, leaving higher boiling "heavier" compounds behind. Fractional distillation uses vapour phase rectification to fractionate compounds and azeotropes by boiling points. — Fractional Distillation
•A full-spectrum cannabis extract preserves the natural ratios of compounds within cannabis while removing any impurities. — Full-spectrum
•Any compound or part of a compound containing only hydrogen and carbon atoms can be considered a hydrocarbon. In cannabis extraction, this term refers mainly to the alkanes, primarily propane, butane, pentane, hexane and heptane. — Hydrocarbon
•Used for securing ground glassware joints to avoid breakage or spilling as a result of joints coming apart.— Keck clamp/clip
•Lipids are organic compounds such as fatty acids or their derivatives and are mostly insoluble in water but soluble in organic solvents. Lipids can be removed through Winterization. See “Winterization”. — Lipids
•A technique in analytical chemistry used to separate, identify and quantify each component in a mixture by their various chemical affinities for the solvent (mobile phase) and the sold media (stationary phase). Other techniques include gas chromatography (GC) and thin layer chromatography (TLC). — Liquid Chromatography
•Also known as solvent extraction and partitioning, it is a method of separating compounds based on their relative solubility in two different immiscible liquids, usually water and an organic solvent (i.e. hydrocarbon). — Liquid extraction
•In liquid chromatography, the mobile phase is a suitable liquid solvent or mixture of solvents. In gas chromatography, it is a gas or mixture of gases. — Mobile Phase
•A short path vacuum distillation type, characterized by extremely low vacuum pressure, generally below 0.01 torr (10 microns). Distance from the heated evaporating surface to the cooler condensing surface must be less than the mean free path (MFP), as determined by the vacuum pressure. — Molecular Distillation
•A density and viscosity sensor that measures properties of flowing fluids with high accuracy and resolution. — Oil Density Sensor
•A phase transition is the transformation of a thermodynamic system from one phase or state of matter to another by heat transfer. The term is most commonly used to describe transitions between solid, liquid and gaseous states of matter. — Phase transition
• Air-operated pumps, usually diaphragm types, that transfer and disperse a wide range of fluids, such as ethanol and oil. — Pneumatic Transfer Pump
•The process of preparing biomass for extraction. Includes analytical testing, stability tests, milling and QA. — Pre-Processing
•The process of further refining extracted resin into other product forms. — Post-Processing
•A type of safety valve used to control or limit the pressure in a system. — Pressure relief valve
•Propane is a three-carbon alkane. It is a gas at STP, stored under pressure inside a tank as a colourless, odourless liquid. Propane extractions run at higher pressures, stripping individual rations of plant waves and oils than butane. — Propane
•Purging introduces an inert or non-combustible purge gas (nitrogen) into a closed system (container or process vessel to prevent fire or explosion). — Purging
•A chemical reactor is an enclosed volume in which a chemical reaction occurs. Typical operating expenses include energy input, removal, raw material costs, labour, etc. Energy changes can come from heating or cooling, pumping to increase pressure, frictional pressure loss or agitation. — Reactors
•A device used in chemical laboratories for the efficient and gentle removal of solvents from samples by evaporation through stirring and moving a thin film throughout the rotating boiling flask, usually under a vacuum. — Rotary evaporator or RotoVap
•Solvent extraction is a process whereby cannabinoids, such as CBD and THC, and cannabidiolic acids, such as CBDa, are separated from plant matter — Solvent extraction
•A fluid state of CO2 when both the temperature and pressure exceed the critical point (>1,100 PSI and >87 F) — Supercritical CO2 Extraction
•Terpenes are naturally occurring fragrant oils that give aroma and taste to many botanicals, including cannabis. —Terpenes
THC, or Δ9-tetrahydrocannabinol, has received the most attention because it is the compound responsible for producing the intoxicating effects  “high” associated with smoked Cannabis. It is present in the flowers and leaves of the Cannabis plant, and was first isolated in the early 1940s — THC,    
•Cannabinoids and terpenes are manufactured in small resin glands on the flowers and primary fan leaves of late-stage cannabis plants called trichomes. — Trichomes
•Versatile equipment with applications in laboratory research, engineering, and industry. A vacuum drying oven is often used for delicate drying processes and for removing flammable solvents. The low-pressure environment minimizes oxidation during drying. —Vacuum oven
•A diaphragm pump (membrane pump) is a displacement pump that uses a combination of the reciprocating action of a rubber, thermoplastic or Teflon diaphragm and suitable valves on either side of the diaphragm to pump a fluid. —Vacuum pump (diaphragm)
•Often referred to as the thickness of a fluid, viscosity defines a fluid's resistance to flow; viscosity is the state of being thick, sticky and semi-fluid consistency due to internal friction. —Viscosity