Preparation of hemp oil
When properly prepared, cannabis oils are an unsurpassed extract in efficiency and purity. The oil is obtained by adding dried cannabis plant raw materials to a solvent, which is then evaporated, leaving the extracted cannabinoid oil. There is an ongoing and widespread debate about which solvents and production methods produce the best oil; however, the method chosen will depend on your geographical location and the availability of suitable solvents for the extraction process. Regardless of the extraction method used, cannabis oil extracts are very versatile in application.
Which solvent to choose for the manufacture of hemp oil?
We do not recommend using any particular solvent; your choice of solvent for oil extraction will depend on on-site availability and your personal preferences. The most common solvents used in the production of cannabis oils are naphtha, acetone, butane, ethanol, and isopropyl alcohol. Whichever solvent you choose, care must be taken during the preparation of the oil, since all these solvents are highly flammable. All solvent evaporation MUST be carried out outdoors in a well-ventilated room, away from heat sources and open flames! As a rule, solvents are divided into one of two categories: they are either polar or non-polar. Polar solvents are water-soluble, and therefore they will also extract water-soluble compounds from the plant, as well as cannabinoids. Non-polar solvents are insoluble in water, and therefore they will extract less water-soluble compounds from plant raw materials. It is worth noting that acetone is an interesting solvent because it is classified as both polar and non-polar. It’s polar — that’s one of the reasons it mixes with water — but it’s also soluble in non-polar substances like hydrocarbons. One of the secrets of obtaining high-quality oil extraction is the complete evaporation of the solvent: high-quality cannabis oils do not contain solvent. You should familiarize yourself with the health and safety information provided with the solvent and take special care when carrying out any extraction process. All the solvents listed below will extract the cannabinoids.
Acetone: Boiling point 135°F (57°C)
Acetone is an organic solvent that evaporates quickly, and for this reason, many consider it one of the safest solvents for oil extraction. Acetone has low toxicity when ingested or inhaled, and it is considered a safe substance to eat because it is naturally produced and disposed of in the human body as a result of normal metabolic processes. Acetone is both a polar and non-polar solvent, which means it will extract some additional compounds other than cannabinoids from the cannabis material. It is available in various purity levels; if this is your preferred solvent, then you are advised to choose acetone with 99.9% purity.
Ethanol (ethyl alcohol or grain alcohol):
Boiling point 172 °F (78°C) Ethanol is the active ingredient of alcoholic beverages, and in concentrated form, it is an effective solvent for the preparation of cannabis oils. However, due to the potential for abuse, many countries have restrictions on the strength and availability of spirits, and therefore they can be extremely difficult to obtain. For example, Everclear is a pure grain alcohol with an extract of 190°C (95% ABV) and the preferred solvent for the preparation of F.E.C.O. (cannabis oil with full extract). However, it is only available in some American states.
Isopropyl Boiling Point (ISO) 180°F (82°C)
Isopropyl alcohol is generally more widely available and cheaper than ethanol. However, it is a different polar solvent, so it also easily dissolves water-soluble compounds from cannabis plant raw materials. Some oil producers believe that, although polar solvents extract the desired cannabinoids, the extraction of other substances is undesirable. Isopropyl alcohol is another polar solvent. Although we do not recommend any particular solvent or process instead of another, we recommend that you do not use isopropanol alcohol for wiping, as it contains additives that make it undrinkable. IPA may also contain detergents and dyes.
Naphtha: Boiling point 86-194°F (30-90°C)
Naphtha is a colorless or reddish-brown flammable hydrocarbon. Its characteristics are very similar to gasoline, and it is usually used as a lighter fluid or as fuel for camping stoves. Generally speaking, less dense (lighter) naphthas will have a higher paraffin content. Naphtha can be carcinogenic, and often products marketed as naphtha contain impurities that may also have their own harmful properties. Inhalation of naphtha vapors can cause symptoms of intoxication, and in severe cases, it can cause depression of the central nervous system. Symptoms of exposure may also include loss of appetite, muscle weakness, impaired motor activity, dizziness, and drowsiness. Prolonged exposure to the skin can cause irritation; excessive exposure can also cause drying and cracking of the skin and associated dermatitis. People suffering from impaired respiratory function may be more susceptible to the effects of naphtha inhalation. As always, evaporate outdoors in a well-ventilated area.