The parameters in the study included:
Dry ice vapor exposure for 1 hour + 5-minute sifting in the Pollinator within a freezer
Dry ice vapor exposure for 48 hours + 20-minute sifting in the Pollinator within a freezer
Their results show that longer dry ice vapor exposure time is crucial (1 hour vs. 48 hours) for the highest trichome purity with zero to minimal green plant matter. And 20-minute sift offered increased trichome collection vs. 5 minutes.
2. Results
2.1. Analysis of Treatment Pilot of Doug Fir Type I Chemovar
The amount of 100 g of fresh cannabis flower was processed for only one hour of dry ice vapor exposure and five minutes of Pollinator sifting treatment (vide infra, Methods, Section 4.9). Despite this, the Kryo-Kief™ dry ice process produced the highest cannabinoid yields, concentrating the total from 24.8 to 60.7% (Extraction ratio: 2.5×) and tetrahydrocannabinolic acid (THCA) from 24.1 to 57.7% (Extraction ratio: 2.4×) (Figure 1). For these calculations, the following equation was utilized.
Terpenoid analysis of this sample showed concentrations of the total from 2.62 to 6.81% (Extraction ratio: 2.6×) and limonene from 0.324 to 1% (Extraction ratio: 3.1×) (Figure 2).
Dry ice kief production from the shortened treatment was low, compounded by this first sample sticking to porous paper. Only 0.5 g was collected, representing 0.5% of original wet weight. The dried kief, in contrast, contained leaf fragments and other extraneous particulate material with a yield of 0.28% of original wet weight (Figure 3). For these calculations, the following equation was utilized.
2.2. Analysis of Treatment Pilot of Astral Works Type II Chemovar
Once more, 100 g of fresh flower was processed for only one hour of dry ice vapor exposure and five minutes of Pollinator treatment (vide infra, Methods, Section 4.9). In this trial, cannabinoid yields of dry ice kief were notably greater than for other samples, increasing the total from 11.8 to 36.7% (Extraction ratio: 3.1×), with THCA increasing from 4.51 to 13.6% (Extraction ratio: 3×) and cannabidiolic acid (CBDA) from 7.26 to 20.4% (Extraction ratio: 2.8×) (Figure 4).
The terpenoid analysis demonstrates much higher yields for dry ice kief in total, from 1.59 to 4.22% (Extraction ratio: (2.7×)) and for each specific compound (Figure 5).
The Kryo-Kief™ yield was 0.1 g or 0.1% of original fresh wet weight (Figure 3c), compared to 0.08 g or 0.08% of wet weight for the dried kief (Figure 3d). Anthocyanin pigmentation, which is a desirable market trait, is maintained in dry ice kief.
2.3. Analysis of Treatment of Tangie Biscotti Type I Chemovar
This sample was run with 200 g of fresh flower with an extended 48 h of dry ice vapor exposure and 20 min of Pollinator treatment (Methods, Section 4.9). Once more, cannabinoid yields were the highest for dry ice kief, with the total increasing from 11.5 to 58.5% (Extraction ratio: 5.1×) and THCA from 11.5 to 56.3% (Extraction ratio: 4.9×) (Figure 6).
Terpenoid total increased from 1.38 to 2.87% (Extraction ratio: 2.1×), with most individual compounds highest in dry ice kief, notably linalool concentrating from 0.0495 to 0.299% (Extraction ratio: 6×) (Figure 7). The dry ice kief appears extremely clean and lighter with rare green flecks (Figure 3e), with a yield of 8.12 g or 4.06% of the original wet flower weight as compared to dried kief with many more particulates and yield of 1.68 g or only 0.84% of fresh weight (Figure 3f).
2.4. Analysis of Treatment of Ursa Major Type I Chemovar
This sample was also treated with dry ice vapor for an extended 48 h and 20 min of pollinator extraction. Cannabinoid total increased from 29.6 to 57.1% (Extraction ratio: 1.9×), with THCA from 27.2 to 53.9% (Extraction ratio: (2×)) and cannabigerolic acid (CBGA) from 1.83 to 3.14% (Extraction ratio: 1.7×) (Figure 8). Terpenoid total increased from 1.41 to 2.73% (Extraction ratio: 1.9×) and linalool from 0.248 to 0.444% (Extraction ratio: 1.8×) (Figure 9). The dry ice kief from this sample is notably cleaner with no green chlorophyll tinge (Figure 3g). A Kryo-Kief™ yield of 6.96% of original fresh weight was ultimately achieved with this chemovar than compared to 1.33% for dried kief (Figure 3h).
The current investigation has demonstrated a practical solventless method for concentrating phytocannabinoids and terpenoids as they appear in fresh inflorescences, thus providing less complex base materials for subsequent usage with the ability to maintain the acid cannabinoids or with the option to pursue subsequent decarboxylation to neutral cannabinoids. The degree of concentration of phytocannabinoids produced here is noteworthy in comparison to traditional sieving as reported in past research on hashish production with yield of 40% THC from the chemovar “Skunk #1” or a 50–55% THC putative upper limit yield with high-tech sieving [11]. Similarly, the achieved concentrations are similar to those realized in solvent extractions (vide infra).
The preservation of lower molecular weight monoterpenoids demonstrated is of particular interest in comparison to prior studies that document significant wastage with drying and curing [8]. Such findings have been corroborated in a more recent study in which fresh varieties expressed higher monoterpene content while dried samples demonstrated lower concentrations after a loss of the lower molecular weight compounds with lower boiling points [12]. While the differences between fresh and dried preparation terpenoid concentrations observed here are less prominent than in the study of Ross et al. [8], this can be attributed to the advanced drying technology regimen applied herein, employing low ambient temperature (vide infra, Methods Section 4.6).
A limitation of this study was that single trials and comparisons were carried out on each of the four chemovars without repetition in order to ensure reproducibility. It is certainly possible that different dry ice exposure times or sifting duration may produce optimized extraction results. Future studies with comparison procedure runs may yield additional data that increase the efficiency and yields of the current methods employed.
you’re kinder than I am myself.
