Effects of Particle Size, Solvent Type, and Extraction Temperature on the Extraction of Crude Cannabis Oil, Cannabinoids, and Terpenes

Abstract

Optimized medicinal plant processing and extraction can improve extract yield and efficiency for valued secondary metabolites while reducing operation costs. This study investigated the effects of the particle size [coarse (2–4 mm), medium (0.5–2 mm), fine (0.25–0.5 mm)], solvents (ethanol, butanol, hexane), and extraction temperature (−20 °C, 4 °C, room temperature) on extracted crude cannabis oil yield and cannabinoid/terpene concentrations using a full factorial design. Results indicate that finer particle size significantly increased the cannabinoid concentrations in the extracts. Ethanol extraction with fine-sized cannabis particles at 4 °C obtained the highest crude oil yield of 28% and had improved recovery rates: 41% for THCA, 36% for CBGA, and higher total terpene concentration (1550 mg/100 g dry matter) in the extracts. Irrespective of temperature and particle size, the solvents produced extracts with different colors: dark green for ethanol, green for butanol, and yellow for hexane. This research provides grinding and extraction conditions with scale-up potential by the cannabis industry to achieve higher crude cannabis oil yield with significant cannabinoids and terpene concentrations.