The Case for Chemohunting: When Art Meets Science in Cannabis Cultivation

Phenohunting has evolved. Learn why chemohunting is the next era of modern cannabis cultivation.

You might assume plants with the exact same genetics and growth environment would have similar aromas, but that’s not always the case. Even with the greatest expertise, breeders can cross plants and end up with progeny that have varying aromatics. Weird, right? We thought so too, which is why we conducted this study.

In collaboration with 710 Labs and SepSolve Analytical Ltd, we examined secondary metabolite profiles between cannabis progeny to see if a detailed chemical analysis would detect aromatic variations across cultivars from the same cannabis lineage grown the same way. Put more simply, when phenotypes are grown the same, do they smell the same?

This might sound cut and dry, but consider the last time you attended a family reunion. Sure, direct siblings share certain traits, but they also have unique differences in appearance, personality, etc. Plus, just because two siblings look alike, that doesn’t make them twins. Spoiler: there are a lot of parallels between this example and our findings in this study.

Not only did we uncover important differences between related cultivars, but we also discovered findings that may lead to the next evolution of modern cannabis cultivation. 

Read on and learn more about our cutting-edge research and catch a glimpse into the high-resolution future of cannabis cultivation.

What is Phenohunting?

If you don’t live and breathe cannabis cultivation, the variety of terms can be confusing. So, before we explain the breeding breakthrough that is chemohunting, let’s cover the foundations of phenohunting.

Phenohunting is the art of selectively breeding plants for their most enticing observable traits. This can include anything from aroma to bud size and color. The key word here, however, is “observable.” Basically, phenohunting is when cultivators select specific plants to continue breeding based on traits they can actually see or smell. 

Once a breeder has identified traits they wish to emphasize in a new generation of plants, they’ll begin the complex cultivation process. F1 Hybrids are created when two “parent” plants from entirely different genetic backgrounds are crossed. When male and female F1 plants are crossed, this results in an F2 hybrid, and so on. 

To stabilize a plant, allowing it to exhibit consistent and robust traits, a breeder will often self-cross a strain for several generations (typically up to the F8 generation). These stabilized strains are known as Inbred Lines (IBL), but this step can also cause genetic deterioration. So, while IBLs are necessary to create a scalable novel F1 hybrid, this process is not without its risks. 

At some point, breeders may need to backcross (BX) a hybrid with one of the original parents to reinforce or correct specific traits. Once a strain is stabilized, breeders often encourage female plants to pollinate themselves to produce First Selfed Generation (S1) seeds. These seeds usually only produce other female plants, so they’re ideal for continued experimentation and propagation.

Phenohunting is a complex process that requires plenty of time, funding, patience, and an individual with no small amount of expertise. These talented individuals can analyze and assess plant traits with unparalleled senses that simply can’t be replicated… and that’s the problem.

 Where Phenohunting Falls Short

Modern cannabis owes much of its exquisite diversity to the unmatched artistry of cultivators. Expert breeders who have mastered phenohunting have produced beloved strains like Gelato 41 and Starburst 36 (where the number denotes the seed the pheno was grown from). There are entire aromatic nuances that wouldn’t exist without the meticulous work of artisanal horticulturalists.  

The issue is that phenohunting relies solely on the views of the individual evaluating each cut. Not only is it subjective to their senses and preferences, but their efforts don’t incorporate the chemical complexities in a plant’s aroma and genetics.

Sure, the cannabis industry is bursting with descriptors in an attempt to convey exactly what a plant smells like (dank, gassy, cheese, loud, etc.) or how intense the psychoactive effects will be. This is, again, all subjective. The only way to assess a plant’s secondary metabolite profile, which includes aromatic and psychoactive compounds, is through analytical testing for quantification.

Plus, propagating hundreds of phenotypes can be time-consuming and expensive. Sure, individuals or even sensory panel groups may be able to qualify distinct nuances in a certain aroma. We’ve developed a vast lexicon of terms to describe the minute details of a plant’s aroma profile. Still, even the most pointed descriptors cannot accurately evaluate the levels of each compound. 

With all the colorful words we could use to describe what kind of fruit a plant smells like, it’s virtually impossible to smell something and say that it has four units of citrus, six units of berry, and one unit of baby poop (thank you, skatole4). That means even the best growers might miss unique phenotypes with low-concentration compounds. 

So, should breeders perform advanced analytical testing on their cuts to decide which ones are worth further propagation? Ideally, yes. For breeders with limited resources, having access to this kind of data will make their efforts more efficient. The problem? The testing capabilities of most labs are not comprehensive enough. 

We know that terpenes alone don’t dictate the complex flavor and aroma of cannabis (shoutout to flavorants!). At the moment, however, testing for basic terpene profiles often overlooks minor non-terpenoid compounds that DO significantly influence flavors and aromas. 

Learn more about flavorants in The Science of Exotic Cannabis: The Dawn of Flavorants

So, what’s the solution? How do we enhance phenohunting practices to capture the complex chemical diversity of cannabis? How do we encourage advanced analytical testing? By promoting an industry where the science of chemohunting and the art of phenohunting go hand-in-hand.

Beyond Terpenes: The Case for Chemohunting

Chemohunting takes all of the best practices of phenohunting and incorporates cutting-edge chemical analysis. We don’t think we’re overselling it when we say it’s the next era in modern cannabis cultivation. Before we get ahead of ourselves, though, let’s start at the beginning.

To understand why there were aromatic differences between cannabis progeny, we analyzed ice hash rosin extracts from five different phenotypes of the same crossing. Specifically, we procured five ice hash rosin samples of Starburst 36 from 710 Labs. These samples have an abundance of aromatic compounds by weight, which made them ideal for our testing instruments. 

Speaking of which, due to the complex nature of cannabis, we needed very specific instruments capable of detecting low-concentration analytes. We used two-dimensional gas chromatography coupled with time-of-flight mass spectrometry, flame ionization detection, and sulfur chemiluminescence detection (GCxGC–ToF–MS/FID/SCD).

The goal of such advanced testing was to characterize the full breadth of flavorants in each phenotype in order to calculate key chemical differences in the aroma profiles. Basically, we wanted hard numbers. 

Additionally, we conducted a sensory analysis by having participants evaluate samples using a questionnaire. Question types included a “check all that apply” descriptor list with thirty-five terms and multiple ranking questions, including citrus, cheese, sweetness, creaminess, overall intensity, and overall preference. 

Results from the human sensory panel were compared with our chemical analysis to validate chemical compositions and reveal specific low-concentration compounds that influence sensory perception.

So, what did we find? The five samples had almost insignificant differences in their terpene profiles. Considering they’re siblings, that generally makes sense. However, there were notable variations in the blind sensory responses, meaning the participants perceived aromatic differences between the samples. 

Comparing their responses to our chemical analysis led to some fascinating discoveries and makes a very compelling case for the practice of chemohunting. Think of it this way — if phenohunting is like pencil and paper, chemohunting is a high-res DSLR. 

The Discovery of a New Tropicannasulfur: 3MHH

If you’re familiar with our Science of Exotic research, specifically the Trio of Tropicanna, you already know that Tropicannasulfurs (TCSCs) are a family of tropical-smelling flavorants. These cannabis flavorants have a citrus-forward aroma with underlying notes of funk, petroleum, and/or sulfur. 

Our chemical analysis detected a previously undiscovered Tropicannasulfur compound, 3MHH or 3-mercaptohexyl hexanoate. Like other TCSCs, 3MHH possesses an intense, sulfuric, and citrus aroma even when found in extremely low concentrations. 

Since 3MHH elutes among several sesquiterpenes, its detection would have been extremely difficult without sulfur chemiluminescence. Why does this matter? Without advanced testing, we never would have known this flavorant played a role in the aroma profile of Starburst 36, let alone that it even existed in cannabis! In this instance, traditional phenohunting practices simply wouldn’t cut it.

Inverse Relationship Between TCSCs and Indole

In three of the samples, we detected indole, a cannabis flavorant with an aroma that can be mothball-like, chemical, or even floral, depending on concentrations. In analyzing this data, we discovered an inverse relationship between TCSCs and indole. 

Learn more about Indole in Science of Exotic Part II: The Curious Case of Chem

This means that higher levels of TCSCs will often coincide with lower levels of indole and vice versa. We don’t know why this relationship exists (yet), but it’s a breakthrough for breeders cultivating sweet or savory flavors. Since these compounds are often found on opposite ends of the Exotic Cannabis Aroma Spectrum, growers can dial in sweet or savory aromas and flavors by chemohunting for specific concentrations.

For example, if breeders want to increase the garlic or cheese aromas, they need to breed for fewer TCSCs since they overpower non-sulfurous compounds. Knowing that high indole means low TCSCs, and vice versa, allows cultivators to breed for specific traits more accurately and efficiently. This is where chemohunting provides a level of insight that phenohunting can’t, especially if two cuts are exceptionally similar

Chemical biomarkers like these aren’t just a game changer for breeders, though. This data can provide helpful definitions for end consumers as well. 

Chemohunting Benefits for Consumers: Aromatypes

Your average consumer might not know or care about the evolution of phenohunting to chemohunting. However, that doesn’t negate that they want and deserve products that deliver specific aromas, flavors, and sensorial effects. 

If the industry adopts chemohunting practices, we can provide consumers with more accurate product information. While strain names are fun and have a deeply rooted history in cannabis culture, the consumer deserves an opportunity to shop for what they want in simple terms driven by data.

For instance, in our previous study, The Science of Exotic Cannabis III: The Trio of Tropicanna, we found that a cut labeled “Gorilla Glue” had been mislabeled. It should have exhibited a more prototypical aroma, but instead, its aroma fell on the sweeter, fruitier end of the Exotic Cannabis Aroma Spectrum. Lo and behold, our testing proved that it truly wasn’t Gorilla Glue.

Whether it was mislabeled intentionally for marketing purposes or unintentionally from a lack of quality control, we still don’t know. We do know, however, that end consumers who might have purchased this cut looking for a specific flavor or effect would have been sorely disappointed. 

So, why does this matter, and what does it have to do with chemohunting? It illustrates the need for two things. One, chemohunting can serve as an important aspect of quality control in addition to breeding efforts. Two, it may be just what the industry needs to create a shared language for more accurate naming conventions.

Terms like “cookies,” “alien,” or even “cheese” often relate more to lineage than flavor experience. As lineages become murky and strain names become less reliable, the industry needs a solution. We can use chemohunting to identify unique “aromatypes” that will make it easier for consumers to make informed purchases.

Imagine there are two cuts of Starburst 36 on the same shelf. However, instead of arbitrary terpene content to distinguish them, one is labeled Starburst 36 (Prototypical: Gas, Creamy, Citrus) and the other Starburst 36 (Sweet: Tangerine, Tropical, Citrus). If descriptors suggested by human sensory evaluation can be proven through advanced chemical analysis, end consumers won’t have to play guessing games. 

Chemohunting: The Harbinger of a Brighter Cannabis Future

We won’t lie. We love being able to say that we’re the ONLY people performing research like this or that we have the only facilities capable of analyzing cannabis in this way. Realistically, though, it makes it really hard for the rest of the industry to adopt chemohunting as a standard practice. 

We will continue identifying unique flavorants and chemo-markers to illustrate the efficacy of chemohunting, and we’ll let you know about it! Additionally, we’ll keep encouraging all analytical testing labs in the United States to invest in our level of instrumentation and chemical standards. Why? It’s the future the cannabis industry deserves.

Do we still have questions? Oh, yes! Honestly, we developed new questions and uncovered more findings in this study than we had time to cover today (Can you say cheese?).

The path to a brighter cannabis future might not be crystal clear. That’s why we’re going to keep asking questions and keep performing studies that enhance our chemical understanding of cannabis aromas. We’re up to the challenge, and we believe the rest of the industry and its many phenomenal growers are, too.

Want more details about the study, our research methods, and our groundbreaking findings? Read all of the details in our White Paper!

Oswald, I. W. H., Paryani, T. R., Sosa, M. E., Ojeda, M. A., Altenbernd, M. R., Grandy, J. J., Shafer, N. S., Ngo, K., Peat, J. R., 3rd, Melshenker, B. G., Skelly, I., Koby, K. A., Page, M. F. Z., & Martin, T. J. (2023). Minor, Nonterpenoid Volatile Compounds Drive the Aroma Differences of Exotic Cannabis. ACS omega, 8(42), 39203–39216. https://doi.org/10.1021/acsomega.3c04496

Twinkle R. Paryani, Manuel E. Sosa, Michael F. Z. Page, Thomas J. Martin, Melissa V. Hearvy, Marcos A. Ojeda, Kevin A. Koby, Jonathan J. Grandy, Bradley G. Melshenker, Ian Skelly, and Iain W. H. Oswald. (2024). Nonterpenoid Chemical Diversity of Cannabis Phenotypes Predicts Differentiated Aroma Characteristics. ACS omega, 9(26), 27755-29071 https://pubs.acs.org/doi/epdf/10.1021/acsomega.4c03225