Botanical Extraction

Plant Varieties and Preparation Methods Impact Phytocannabinoids in Cannabis Oils

Written by Petar Petrov

Despite the popularity of cannabis oils, no study has examined the correlation between the cannabis variety of the source material and the extraction method and cannabinoid composition of the resultant oil.

To fill that gap in our knowledge, a team of scientists from Italy undertook a study on “the Italian panorama of cannabis oils,” spanning the period between 2017 and 2019 and 8,201 oils.

Out of those 8,201 specimen, 3,457 were excluded because of the absence of pharmaceutical-grade, standardized cannabis varieties and/or the use of non-standardized extraction methods.

Four standardized cannabis varieties were used to limit variables: Bedrocan®, Bediol®, Bedrolite®, and FM2.

While all four varieties contained delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), Bedrocan was characterized by its THC content, Bedrolite by its CBD content, and Bediol and FM2 by the content of both cannabinoids.

Four preparation methods were used, “mainly based on maceration of vegetable materials in olive oil at high temperature, at about 100oC or more.” Two of those methods (A and B) didn’t require preliminary decarboxylation.

  • Method A: Extract in oil at 98° C for 1 hour
  • Method B: Extract in oil at 110° C for 2 hours
  • Method C: Decarboxylate at 115° C for 40 minutes; extract in heated oil (100° C) for 40 minutes
  • Method D: Decarboxylate at 145° C for 30 minutes; extract with ultrasound (35 kHz) for 30 minutes

The researchers note that the “main differences in the cannabinoid profile[s] are due to the decarboxylation step and especially to the heating time and temperature applied. These differences are directly related to the percentage of acidic forms of cannabinoids.”

The lack of preliminary decarboxylation in extraction methods A and B was correlated to a highly variable ratio of acidic (tetrahydrocannabinolic acid, THCA) to neutral (THC) cannabinoids, reducing these approaches’ reproducibility. Not decarboxylating, of course, resulted in more acidic cannabinoids in the final products. The mean percentage of acidic cannabinoids in methods A and B ranged from 45-48%, with 52-55% neutral THC or CBD.

Method C used extraction in oil by means of water bath, whereas method D employed ultrasound. Both produced oils richer in active neutral cannabinoids, which is to be expected since that’s what decarboxylation entails. Method C resulted in 93% THC and 79% CBD, whereas method D provided the highest neutral cannabinoid levels at 99% and 97% for THC and CBD, respectively.

The biggest factor in the final products’ cannabinoid content was the source material, which couldn’t be matched by any sample preparation and extraction method. After all, you can’t make silver out of steel.

The authors state that the “relevance of these studies lies in ensuring a conscious prescription by the physicians, who should take into consideration both the composition and stability of cannabis oils.” Many of the concepts within the study have already been known by most of the people within the industry, such as the authors reporting “a clear trend in cannabinoid content with respect to the preparation methods” or “those methods with the preliminary decarboxylation step… allowed obtaining oils richer in the active neutral form.”

But validating what’s already been known for decades with studies like this one can only bolster the stance of cannabis medicine. The physicians, who will consult scientific journals for guidance, will educate themselves on cannabis (to ensure “conscious prescription”) the way many other people already have from intimate or self-educated techniques.

Image Credits: Sherpa SEO, Wikimedia Commons, CC BY 3.0


  1. Dei Cas M, et al. Phytocannabinoids profile in medicinal cannabis oils: The impact of plant varieties and preparation methods. Front Pharmacol. 2020;11:1752. Journal Impact Factor = 4.400

About the author

Petar Petrov

Petar is a freelance writer and copywriter, covering culture, art, society, and anything in-between that makes for a nice story. And as it so happens, cannabis is a great element to add to each of those conversations.