Ethanol Extraction Experiments

Low Temperature Cannabinoid Extraction of Decarboxylated Cannabis

Approximately 33.2 grams of cannabis flower material was powdered in a blender and heated to 250°F (121°C) for 27 minutes.  The post-decarboxylation weight was 29.0 grams.  Approximately 25 grams of this decarboxlyated material was placed in a paper filter and suspended in a one-quart mason jar.  One hundred twenty five milliliters of  ethanol (Everclear brand 95% grain alcohol) was poured into a separate jar and both jars were placed in a freezer for one hour at an approximate temperature of 8°F (-13°C) .  The 125 ml of ethanol was poured onto the filter paper containing  the 25 grams of powdered cannabis and immediately returned to the freezer.  The alcohol was allowed to percolate through the cannabis material and collect in the bottom of the jar. After 12 hours, the paper filter containing the cannabis was moved to an empty mason jar and the filtrate from the first extraction was retained in the first mason jar.  The process was repeated twice more; (using fresh ethanol) yielding a total of three ‘washes’ of  cannabis tincture.  The leached (‘spent’) cannabis material was dried and saved for later analysis.


Wash 1: 41 grams   Wash2: 108 grams      Wash 3: 108 grams

In preparation for analysis by gas chromatography, one ml samples (approximately 880 mg each) of each of the three ‘washes’ were diluted in the ratio of one ml of cannabis extract ‘wash’ to 23 ml of denatured alcohol.  In order to determine the presence of  chlorophyll,  the three diluted extract solutions were analyzed for absorbance spectra using a Vernier Go Direct SpectroVis Spectrophotometer.

The absorbance spectra  for the diluted ‘wash 1’  is shown below (right). For reference, an absorbance spectral plot of chlorophyll is also shown below (left).  Absorbance peak data  (430 nm and 660 nm) for all three ‘washes’ is shown in the spreadsheet below.


Low Temperature Decarboxylated Cannabis ‘Wash 1’ diluted extract

 (absorbance vs. wavelength) graph

Absorbance Spectra of Diluted (Low Temperature Decarboxylated Cannabis) Ethanol Extract

Room Temperature Cannabinoid Extraction of  Decarboxylated Cannabis

In order to determine whether the low temperature extraction method is superior to room temperature extraction. The above-referenced extraction was repeated with similar decarboxylated cannabis material at room temperature (approximately 72°F, 22°C).  Three ‘washes’ were recovered as before and analyzed for absorption at 430 and 660 nm.  Higher absorbance suggests a higher chlorophyll content in the extract solutions.

Low Temperature Cannabinoid Extraction of Non-Decarboxylated Cannabis

Cannabinoid extraction was performed as before using cannabis material that had not been heated prior to extraction with ethanol.  Samples were prepared for adsorption spectra analysis as before.  Results from all three extractions are shown below

Absorption vs. Wavelength of Cannabis Extract Solutions

THC Analysis

Diluted extract ‘wash’ solutions and flower materials were analyzed for THC  concentration using an SRI Model 420 gas chromatograph. Results are corrected by the PeakSimple software to show the concentration of the undiluted sample.  Data from the room temperature extraction of non-decarboxylated material is not shown here due to the difficulty of analyzing non-decarboxylated material using the Model 420 Gas Chromatograph.  CBD and CBG were not detected in significant amounts.  Sample chromatograms are shown below:

Wash 1

‘Wash 1’  Extract of Decarboxylated Cannabis Material

Low Temperature Extraction

Decarboxylated Cannabis ‘Flower’ Material


Low Temperature Extraction

Decarboxylated Cannabis Material


Low Temperature Extraction

THC Analysis Data

THC analysis data from the Gas Chromatograph and mass balance calculations 

 are reported  in the spreadsheets below

Decarboxylated Cannabis Material 

Low Temperature Extraction

Alcohol Extract of Decarboxylated Cannabis Material 

Low Temperature Extraction

Alcohol Extract of Decarboxylated Cannabis Material 

Room Temperature Extraction


The room temperature extraction of decarboxylated material resulted in greater extraction of chlorophyll.  THC and chlorophyll extraction were  highest in the first wash.

The low-temperature extraction of decarboxylated material resulted in lower extraction of chlorophyll. THC extraction was highest in the second wash and chlorophyll extraction was highest in the last wash.

Low-temperature extraction of non-decarboxylated material was not analyzed for THC content, but absorbance data suggests that it contained a greater amount of chlorophyll than the extracts made from decarboxylated material.