The easiest way to synthetically recreate the terpene profile of a given cannabis variety is to quantify its terpene content analytically and then individually add terpenes together to create a flavor Master Mix. The analytical instrument best suited for the job of quantifying terpene levels in a given cultivar is a mass spectrometer (MS).
A mass spectrometer works by removing electrons from a given molecule, causing it to adopt an overall positive charge. The charged molecule is then shot through a tunnel surrounded by high-energy magnets,and hits the detector, causing a spike on the digital output. Using advanced differential equations (calculus), the MS software can deduce with pinpoint accuracy the exact number of particles of a given mass that hit the detector, and once the entire sample has been analyzed, can deduce the relative percentages of each mass product. This will in turn give an experienced technician all the data they need to deduce the exact terpene composition of a cultivar.
Terpenes are small organic molecules that all have basically the same molecular weight and polarity, and are volatile. Therefore, the most suitable combination for terpene analysis is a gas chromatograph/mass spectrometer—or GC-MS. Like other types of chromatographic equipment, a gas chromatograph separates the individual components from the starting bulk of a sample. Unlike other chromatographs, a GC vaporizes the components into the gas phase before sending it on into the MS.
The advantage of using a GC for small molecule analysis is that it allows a bigger separation between molecules with very similar physical properties (boiling point, molecular weight, polarity, etc.). A GC-MS uses data from both instruments to determine the final composition of a sample. So, in sum, a GC-MS provides spectacular results for doing terpene analysis.
Once a printout of the terpene composition is achieved, manufacturers can purchase the individual reagents and combine them quantitatively to recreate the terpene profile of the original flower. The advantage of using this method is consistency of flavor, greater ability to perform Quality Assurance/Quality Control, and the ability to prepare large batches of Master Mixes, in advance, that help streamline the manufacturing process.
However, one of the greatest current disadvantages to synthetically recreating a cultivar terpene profile is the limitation of how many terpenes you test for. Cannabis is thought to possess over one hundred individual terpenes of various concentrations. However, most analyses only test for 30-40 terpenes, and many vapes contain as little as 15. So, recreating the original flavor is clearly unachievable under these conditions.
There are also knowledge limitations regarding cannabis chemistry that prevent successful flavor recreations. After all, you can’t add in what you don’t know. As more experimentation is conducted, scientists will develop a more comprehensive understand of which molecules specifically affect flavor and aroma.
Theoretically, the levels of terpenes for those compounds that are tested for and included in the Master Mix should be equal to those found in the original bouquet. In practice, that is not the case. User error when making the Master Mixes, purity concerns from the terpene manufacturers, and whether synthetic or native terpenes are used all come into play when assessing the flavor of the final product. Another cause for differences is that native terpene compounds that are sold on the market rarely come from cannabis itself, but rather from some other plant that is legal to grow, produces the terpene at higher levels, and is easier to extract from (i.e. α- and β-Pinene from pine trees, D-Limonene from citrus fruits, etc.).
The best way to recreate the original bouquet of a plant is to re-administer terpenes from the original cultivar back into the vape oil once the extraction and purification process is complete. In practice, there are major challenges to overcome before this process can properly function and be scaled up.
In a subsequent post, we’ll talk about some of these limitations.