Preparation of Cannabis Glycerin Extract with Ultrasonics
- Cannabis extraction in glycerin is a comfortable way to extract cannabinoids directly from the dry plant material.
- Cannabis glycerin concentrates can be easily formulated in any kind of cannabis-infused product such as tinctures, vapes, baking ingredient, lotions etc.
- Ultrasonic extraction is a superior method to prepare cannabis concentrates. By sonication, the extraction yield is significantly increased, whilst extraction time is decreased to a few minutes.
How to Prepare a Cannabis Glycerin Concentrate
For the conventional cold process preparation of a glycerin tincture, the cannabis buds are generally soaked for approx. 90-120 days in glycerin to extract the active substances. The cold process is very time-consuming, but it has the advantage over the faster hot extraction that the active compounds such as THC, CBD, terpenes etc. are not degraded by heat. Ultrasonic extraction is a non-thermal process, which can be carried out at room temperature. Within a few minutes, a complete extraction of the active compounds of cannabis can be achieved without thermal degradation. The cold process extraction yields also in a tastier tincture, since the aromatic terpenes are preserved.
A basic recipe for ultrasonic extraction of cannabis in vegetable glycerin includes the following steps:
- 400mL (approx. 8 ounces) of food-grade vegetable glycerin
- 35 grams of dried cannabis (buds, flowers, leaves or stems)
The ratio of cannabis : glycerin can be adapted to the cannabis quality and the desired strength of the final product. The amount of vegetable glycerin and cannabis can be scaled up or down respectively the desired production volume of glycerite.
Please note that extracts from buds and flowers are tastier. However, effective cannabinoids can be extracted from stems, too.
Cannabis extraction with the ultrasonicator UP400St
Step-by-Step-Protocol for Ultrasonic Cannabis extraction in Glycerin
- Decarboxylation (optional): Both, decarboxylated as well as not decarboxylated cannabis can be extracted via the following steps. To obtain a highest THC potency, decarboxylation is definitively recommended. To obtain a most effective cannabis tincture, it is recommended to decarboxylate the cannabis plant material. This can be easily done by heating the cannabis on a baking sheet in the oven. Therefore, preheat the oven to 240°F / 115°C. Bake the cannabis for 30 to 40 minutes, stirring every 10 minutes so that it toasts evenly. Let the cannabis cool down before further processing.
- Ultrasonic extraction:
2.1. Preparation: 35 grams of the dry, crushed cannabis plant material is added into a glass beaker with 400mL vegetable glycerin. The beaker with the glycerin-cannabis mixture is placed into a larger container containing an ice-bath. If necessary, replace the ice when melting during sonication to ensure a rapid heat dissipation to maintain a temperature not higher than 30°C.
2.2. Sonication: Ultrasonic extraction is performed with the ultrasonic processor UP400St with probe S24d40. The probe (also known as tip, horn or sonotrode) of the ultrasonic processor UP400St (400W, 24kHz) is immersed approx. 4cm into the vegetable glycerin. Set the amplitude via the digital touch display at 50%. Sonicate the mixture for 3-4 minutes whilst moving the ultrasonic probe slowly through the glycerin. - Straining the glycerite: To remove the plant parts from the cannabis glycerin concentrate, strain the glycerin. Since glycerin is viscous and sticky, the use of a fine metal strain or a strainer bag has been proven to be the easiest.
- Storage: Store in a glass container at a dark and cool place. When properly stored, cannabis glycerin tinctures have a shelf life of approx. 1 year.
UP400St – Ultrasonic Extraction of Cannabis in 8L Agitated Batch Setup
As alternative liquids for the above described ultrasonic extraction / infusion process, coconut oil, olive oil, canola oil, or butter can be used. Coconut and olive oil are preferred if the cannabis concentrate should be processed further to an edible cannabis emulsion.
Click here to learn more about the ultrasonic emulsification of cannabis oil!
Advantages of Ultrasonic Cold Extraction
- high speed extraction
- no thermal degradation
- tastier tincture
- high yield, high potency (effective)
- high quality (aromatic & tasty)
- stable emulsification for various product formulations
How to Prepare Cannabis E-Juice
Cannabis can be consumed as e-juice (or e-liquid, vape juice) or vapes smoked in a e-cigarette. For the formulation of cannabis-infused e-juice, food-grade propylene glycol (PG) gives the best results. Alternatively, vegetable glycerin or a mixture from vegetable glycerin and propylene glycol (e.g. ratio 7:3) can be used for the production of cannabis e-liquids to fill e-cigarette cartridges, too.
- 500mL of propylene glycol (PG)
- 30 grams of fine crushed cannabis (dried, decarboxylated)
Alternatively, a mixture of vegetable glycerine and propylene glycol with a ration of 7:3 can be used. (7 parts vegetable glycerine to 3 parts propylene glycol)
- Ultrasound Extraction: The beaker with the propylene glycol – cannabis mixture is placed into a larger container containing an ice-bath. If necessary, replace the ice when melting during sonication to ensure a rapid heat dissipation to maintain a temperature not higher than 30°C.
Sonication: Ultrasonic extraction is performed with the ultrasonic processor UP400St with probe S24d40. The probe (also known as tip, horn or sonotrode) of the ultrasonic processor UP400St (400W, 24kHz) is immersed approx. 4cm into the vegetable glycerin. Set the amplitude via the digital touch display at 50%. Sonicate the mixture for 3-4 minutes whilst moving the ultrasonic probe slowly through the glycerin. - Straining the cannabis e-juice: To remove the plant parts from the cannabis glycerin concentrate, strain the glycerin though filter paper or a fine mesh.
- Storage: Store in a glass container at a dark and cool place. When properly stored, cannabis e-juice have a shelf life of approx. 12-24 months.
Portable ultrasonicator UP100H for efficient botanical and mushroom extraction.
Hielscher Ultrasonicators for Cannabis Extraction
Hielscher Ultrasonics is your supplier for powerful, reliable ultrasonic systems. Our ultrasonic systems range from bench-top and pilot plant to full industrial processing. Our robust ultrasonic systems can be used for batch and inline processing. Easy and precise control over all process parameters ensure consistently high extract quality and high process efficiency.
- high efficiency
- state-of-the-art technology
- reliability & robustness
- batch & inline
- for any volume – from small beakers to truckloads per hour
- scientifically proven
- intelligent software (e.g., pre-settings)
- smart features (e.g., data protocolling)
- CIP (clean-in-place)
- simple and safe operation
- easy installation, low maintenance
- economically beneficial (less manpower, processing time, energy)
- Quality Made in Germany
The table below gives you an indication of the approximate processing capacity of our ultrasonicators:
| Batch Volume | Flow Rate | Recommended Devices |
|---|---|---|
| 1 to 500mL | 10 to 200mL/min | UP100H |
| 10 to 2000mL | 20 to 400mL/min | UP200Ht, UP400St |
| 0.1 to 20L | 0.2 to 4L/min | UIP2000hdT |
| 10 to 100L | 2 to 10L/min | UIP4000 |
| n.a. | 10 to 100L/min | UIP16000 |
| n.a. | larger | cluster of UIP16000 |
Facts Worth Knowing
Glycerites
A glycerite is a fluid extract of an herb or other medicinal substance made using glycerin as the major extraction liquid.
Glycerin (also called glycerine or glycerol) is a sugar alcohol. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in all lipids known as triglycerides. It is widely used in the food as well as in pharmaceutical products. Glycerol has three hydroxyl groups which are responsible for its solubility in water and its hygroscopic nature. Glycerin functions as both a solvent and a preservative. Glycerites are advantageous as medical carrier fluid due its sweet taste and lack of alcohol. The advantage of glycerin over an alcohol tincture lies in the fact that glycerin does not degrades the botanical constituents whilst alcohol tends to denature them.
Cannabis infused glycerin tinctures can be well stored in a dark, dry cool place, but they do not show the same long-time stability/shelf life as alcohol based tinctures. Refrigeration helps to prolong the stability and is thereby recommended.
Cannabis glycerin tinctures are cost effective in production and offer a safe, alcohol-free dosage form to medicate cannabis.
Decarboxylation
Delta9-tetrahydrocannabinol (THC) is the main psychoactive substance in cannabis. A live, green cannabis plant does not contain a lot of THC. Instead, a relatively high amount of tetrahydrocannabinolic acid (THCA) can be found. THCA shows no psychoactive effects and will not cause the “high” effect. Therefore, THCA must be transformed into the psychoactive THC. The transformation of THCA into THC can be achieved by decarboxylation. By decarboxylation, the carboxyl group -COOH is removed from the THCA molecules.
By decarboxylation, the cannabis develops an aromatically roasted or toasted taste. However, even if decarboxylation comes with many advantages, some users prefer to process and consume non-decarboxylated cannabis as during the decarboxylation smaller monoterpenes and sequiterpenes, phenols, ketones, aldehydes, ethers, and esters may evaporate.
Marijuana consists of the dried flowers and subtending leaves and stems of the female Cannabis plant (mostly Cannabis sativa). This is the most widely consumed form and it contains approx. 3% to 20% THC. Specific, highly bred forms of marijuana reach a THC content of more than 30%. Marijuana is the source material for all other varieties of THC-containing cannabis products. To convert the most abundant cannabinoid, tetrahydrocannabinolic acid (THCA), into the psychoactive THC, a decarboxylation process must be initiated. Therefore, the cannabis plant or its extracts must be heated to cause a decarboxylation process. During decarboxylation, the non-psychoactive THCA is converted to the psychoactive THC.
Hashish or hash is a concentrated resin form (e.g. formed as cake or ball) that is either produced from pressed kief or from the resin that is scraped from the surface of the plant and rolled into balls. It occurs in various colors from black to golden brown depending upon purity and source. It is consumed orally (e.g. as tincture or as ingredient in food) or smoked. For smoking, various consumption types are known, e.g. in a pipe, hookah, bong, bubbler, vaporizer, via a hot knife, smoked in joints, mixed with cannabis buds or tobacco, or smoked as bottle tokes.
Cannabis Tincture refers to the extract of cannabinoids in alcohol or vegetable glycerin. The cannabinoids are extracted from the cannabis plant using high-proof spirits (mostly grain alcohol) or vegetable glycerin as solvent.
Hash oil is a resinous matrix of cannabinoids produced by solvent extraction, formed into a hardened or viscous mass. Hash oil is one of the most potent cannabis products because of its high level of psychoactive compound THC. The use of hash oil extracted in butane and supercritical carbon dioxide has recently gained an increasing popularity. Hash oil is often ultrasonically processed to an emulsion. Click here to learn more about the ultrasonic emulsification of hash oil!
Infusions refer to different kinds of cannabis infusions which differ from each other by the broad variety of non-volatile solvents which can be used for the preparation of cannabis infusions. To prepare such infusion, cannabis plant matter is mixed with a solvent and then pressed and filtered to transfer the oils from the plant into the solvent. Cocoa butter, dairy butter, cooking oil, glycerine, and skin moisturizers are commonly used solvents. Click here to learn more about the ultrasonic extraction of cannabis!
Medical marijuana refers to the use of the Cannabis plant as a herbal therapy or the use of its active compounds such as synthetic THC and cannabinoids. This usage generally requires a medical prescription. Scientific research has shown that the use of cannabis or its derivatives has positive impacts against e.g. chemotherapy-induced nausea and vomiting, neuropathic pain, and multiple sclerosis.
Literature/References
- Casiraghi A., Gentile A., Selmin F., Gennari C.G.M., Casagni E., Roda G., Pallotti G., Rovellini P., Minghetti P. (2022): Ultrasound-Assisted Extraction of Cannabinoids from Cannabis Sativa for Medicinal Purpose. Pharmaceutics. 14(12), 2022.
- Da Porto, C.; Natolino, A.; Decorate, D. (2015): Effect of ultrasound pre-treatment of hemp (Cannabis sativa L.) seed on supercritical CO2 extraction of oil. J Food Sci Technol 2015 Mar 25;52(3):1748-53.
- Djenni, Zoubida; Pingret, Daniella; Mason, Timothy J.; Chemat, Farid (2012): Sono–Soxhlet: In Situ Ultrasound-Assisted Extraction of Food Products. Food Analytical Methods. 2012.
- Karami, Z.; Yousefi, G.; Alipour, M.; Emam Djomeh, Z.(2013): Modeling and Optimization of Ultrasonic Assisted Extraction (UAE) of Oil from Cannabis with RSM.
- Suslick, K.S. (2001): Sonoluminescence and Sonochemistry. Encyclopedia of Physical Science and Technology; R.A. Meyers (ed.): Academic Press, San Diego, 2001.