TOPICS

Welcome to Topics!  Below you will find many cannabis-related articles that are geared towards newbies and laboratory veterans alike.  If you’re brand new to cannabis and need help with the lingo, read Terminology at the very bottom of this page before you dig in.

TABLE OF CONTENTS (Click One)

Basics of Cannabis Extraction

Put simply, extraction is the process of separating target compounds from some form of raw material (typically biomass) to obtain a concentrate.  In the cannabis industry, cannabinoids, terpenes, and other plant compounds may be separated from raw cannabis biomass to obtain numerous types of cannabis concentrates.  Cannabis extraction methods are commonly classified as either solvent extraction or solventless extraction.  As the name implies, solvent extraction employs the use of solvents to separate target compounds from cannabis biomass, whereas solventless extraction uses other means, such as mechanical separation.

Solvent extraction starts with soaking cannabis biomass in solvent to dissolve the cannabinoids, terpenes, and other plant compounds.  The solvent mixture containing the target compounds (known as “miscella”) is physically separated from the biomass and subsequently filtered through micron-sized filters (0.5 – 10 μm).  Finally, the solvent is evaporated to obtain a concentrated oil/wax that contains mostly cannabinoids and terpenes.  There are many different solvents used in cannabis extraction, including but not limited to:

  1. Hydrocarbons– The most commonly used hydrocarbons are butane and propane, but other hydrocarbons such as pentane, hexane, and heptane could be used (very uncommon).  Butane and propane are preferred by many processors due to their extremely low boiling points, which allows the solvent to be completely purged with little to no heat.  Since terpenes are very heat sensitive, these solvents are perfect for terpene preservation.  Hydrocarbons also dissolve significant amounts of plant lipids that are not desired in some cannabis products, such as distillate and shatter.  The extraction of undesired lipids can be reduced by using extremely cold solvent, but usually hydrocarbon extracts must be winterized (see Winterization) when producing refined products such as distillate.
  2. Supercritical CO2 (carbon dioxide) – Carbon dioxide may be used as a solvent while in a supercritical state, meaning it is neither gas nor liquid, but a physical state somewhere in-between.  Achieving this supercritical state requires incredibly high pressures and increased temperatures, but it gives CO2 unique solubility properties, and oftentimes parameters may be fine-tuned in order to develop a selective extraction process.  In practice, using supercritical CO2 produces cannabinoid extracts with significant amounts of undesirable lipids and fats (similar to hydrocarbons), requiring the extract to be winterized if used to produce cannabis distillate.  CO2 extraction is generally limited by scalability (the ability to process larger and larger amounts of biomass) due to challenging pressure requirements.
  3. Cold Ethanol – Ethanol is an excellent choice of solvent for refined products, like distillate, especially when used at super cold temperatures (-40 to -80 °C).  When cannabis is extracted with chilled ethanol, most lipid contaminants are avoided from the beginning, eliminating the need for winterization (some processors elect to winterize after extraction anyway).  Disadvantages to ethanol extraction include large amounts of solvent that must be recovered and the notion that terpenes obtained from this mode of extraction are mediocre at best.  In fact, ethanol extraction is almost never used for products that rely on exceptional, cannabis-derived terpenes.  Ethanol is almost exclusively used to produce cannabis distillate, which is completely stripped of all terpenes.
  4. Warm Ethanol – Although less popular, ethanol is also used at room temperature for extraction.  This method picks up far more contaminants than chilled ethanol, and is consequently paired with other purification techniques, such as winterization, solid-phase extraction, and the use of various other filter medias and adsorbents.  Typically, ethanol extraction facilities opt to use chilled ethanol to avoid these added purification steps.

Winterization

Winterization is a purification (refinement) process that takes advantage of differences in solubility, a physical property of matter.  In almost all cases, the solubility of a substance dissolved in a liquid decreases as temperature of the liquid decreases, and vice versa.  Winterization is used to remove undesirable lipids (fats) from crude, un-winterized cannabis oil that are typically extracted as a consequence of using solvents, such as hydrocarbons (butane, propane), CO2, and warm ethanol, in the extraction process.  Winterization is used to make cannabis distillate and other refined products.

In general, winterization is performed by:

  1. Dissolving un-winterized crude oil (usually obtained from hydrocarbon, CO2, or warm ethanol extraction) in pure ethanol and chilling the mixture (commonly -20 to -40 ºC).  Undesirable lipids aggregate into solids because they have an especially low solubility in cold ethanol.
  2. The solid lipids are then filtered away from the cannabis oil solution (dissolved in ethanol), similar to how coffee grounds are filtered and separated from the coffee you brew in the morning.
  3. The filtered solution (cannabis oil dissolved in ethanol) is concentrated by evaporating the ethanol using a solvent recovery system.  After the ethanol is completely removed, an extremely viscous oil is left behind; this is the product of winterization.

Note that “lipids” are a very large class of molecules that actually include cannabinoids and terpenes.  While cannabinoids and terpenes are technically lipids, they do not solidify in ethanol like the majority of other plant lipids, making ethanol an especially convenient and advantageous solvent for winterization.  In addition to convenience, ethanol is generally recognized as safe (GRAS) by the Code of Federal Regulations, making it a bit less worrisome to use in manufacturing processes.

If you’re wondering, “why not use cold ethanol to extract in the first place and avoid all those lipid contaminants from the start?“, see Basics of Cannabis Extraction, item #3.

Delta 8 THC - What Is It?

Delta-8 THC is a geometric isomer of Delta-9 THC; it is exactly the same chemical structure, besides the placement of one double bond.  D9-THC is the compound in cannabis responsible for its traditional intoxicating effects.  D8-THC is far less intoxicating than D9-THC, which is why many users prefer it.  Think of Delta-8 as Delta-9’s little brother.

  1. Will I fail a drug test if I use Delta-8 THC?
    A:  YES is the short answer.  The long answer: it depends.  You will likely fail a drug test if they are testing for THC because it is difficult to discern between D8 & D9-THCs.  A typical drug test screens for THC metabolites, and since D8 & D9 are so similar, most tests are unable to tell the difference.
  2. Is Delta-8 THC found in cannabis naturally?
    A:  YES, D8-THC occurs naturally in cannabis, but in minuscule amounts.
  3. So my D8 vape pen and D8 gummies are made from naturally extracted Delta-8 THC right?
    A:  NO, of course not. D8 THC is found in minuscule amounts in cannabis. Although theoretically possible, no one extracts cannabis with the intent to purify the negligible amount of D8 on it.  Instead, manufacturers extract and purify CBD (cannabidiol) and subsequently convert CBD to Delta-8 THC using chemical synthesis.
  4. But my D8 product says “Extract” right on the packaging.
    A:  I guess it depends on your definition of the word “extract”.  The CBD is extracted and purified using solvents and fancy equipment, but no chemical synthesis is necessary to obtain 99% pure CBD.  The CBD is then reacted with an acid catalyst, producing synthetic D8-THC.

Delta-8 THC is manufactured synthetically by chemically reacting CBD with an acid. In general, the following steps are taken:

  1. Hemp is extracted using solvent, and the solvent is evaporated to obtain a crude oil containing mostly CBD and a vast array of other plant compounds.  Google: ethanol extraction of hemp.
  2. The crude oil is distilled under high vacuum to purify the cannabinoids in it, producing CBD distillate that is 80-90% CBD.  Google: wiped-film distillation.
  3. CBD distillate is crystallized by dissolving in pentane and cooling the solution until white crystals form.  The crystals are dried in vacuum ovens until all the solvent is removed.  This process is known to completely remove THC, pesticides, and other contaminants from the CBD isolate.
  4. CBD isolate (99% pure) is reacted with an acid catalyst to first form D9-THC, which subsequently isomerizes into D8-THC.

Terminology

Cannabinoids – The major components of cannabis extracts.  There are too many to list, but some of the most notable are THC, CBD, THCA, CBDA, CBG, CBN, CBC, and THCV.

Chemical Property – a property of a substance that can only be measured by changing the chemical makeup of the substance i.e. the atoms are changed

Crystal – a homogenous solid that has an organized, uniform pattern extending in all dimensions.

Heterogenous – Something that is not consistent throughout. For example: milk and cereal, chocolate chip cookies, trail mix, and liquid mixtures that separate like oil and water.

Homogenous – Something that is consistent and uniform throughout. For example, sweet tea, saltwater, milk, syrup, and cooking oil.

Lipid – A broad classification of compounds that includes many natural oils, fatty acids, waxes, triglycerides, steroids, etc. Cannabinoids and terpenes are also lipids.

Oil – A lipid that is liquid at room temperature, such as distillate, crude oil, and other products that take the shape of their container.

Mixture – In chemistry, a mixture is combination of two or more substances and can be either homogenous or heterogenous.  Mixtures can be solutions, colloids, or suspensions.  The components of a mixture do not react or combine with each other chemically.

Physical Property – A property of a substance that can be measured without changing the chemical makeup of the substance i.e. the atoms of the molecule do not change or rearrange when you observe or measure this property.

Refined Products – Cannabis products that are purified (aka refined) after extraction. One or more refinement processes may be used.  Common products include distillate and shatter.

Solubility – A physical property that describes how much of a substance can dissolve in a solvent (i.e. how much salt can dissolve in a fixed amount of water).

Solution – In chemistry, a solution is a homogenous mixture of two or more substances.  For example, salt dissolved in water is a solution because the salt is evenly distributed throughout the water.

Solvent Recovery System – A broad term used to describe a machine that removes solvent (ethanol, butane, etc.) from cannabis extract. An example is a rotary evaporator being used to remove ethanol from ethanol extract to product concentrated crude oil.

Strain –  All varieties of cannabis are unique, just like humans.  Their uniqueness is derived from their genetics (DNA), which influences every characteristic of a cannabis plant: smell, color, height, leaf shape, resiliency, and of course, how much THC and other cannabinoids are produced.  A particular genetic line (seed line) that has unique characteristics is widely accepted as its own “strain”.  Strains are kept alive over the years by cloning and special breeding techniques.

Terpenes – A large group of compounds that are responsible for the flavor and smell of cannabis.  The endless combinations of different terpenes in differing amounts are responsible for the unique fragrance of each strain of cannabis.

Throughput – The amount of something that is generated or processed in a given amount of time. For example, the amount of cannabis biomass that can be extracted per hour of operation, or the amount of vape carts that can be produced per hour.

Volatile – Volatile compounds (or solvents) generally have low boiling points, which means they release significant amounts of vapor. Terpenes are extremely volatile because they produce significant amounts of vapors, even when cold or at room temperature.

Wax – A lipid that is solid at room temperature, such as cannabis budder, badder, and other products that do not take the shape of their container.

 

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