Science of Smokability Phase I Results

The results are in!

Phase I of the Science of Smokeability study is complete and there are already some valuable insights for pre-roll producers in the results that could gain you customers and save you money.

The Science of Smokeability is a multi-year research project, spearheaded by Custom Cones USA and the DaySavers brand in partnership with the Cannabis Research Coalition and The Network of Applied Pharmacognosy ( NAP), that aims to revolutionize our understanding of cannabis cultivation, processing and consumption.

This study is a first-of-its-kind, peer-reviewed scientific assessment of how various cultivation and production techniques affect the product from the consumer standpoint.

Unlike previous studies, the Science of Smokeability uses a combination of both laboratory research involving a smoking machine and instruments to measure various components of the smoke, and a survey of consumers that tested pre-rolls sent out by scientists. Together, the results give us a wider and fuller look at how different production and cultivation variables play out in the finished, consumer version of products.

Led by Dr. Allison Justice and Dr. Markus Roggen, known for their groundbreaking work in exploring the hypotheses behind the color change of ash in cannabis smoking, the first phase of the study looked at water activity and moisture content.

What Are Water Activity and Moisture Content?

While similar, water activity and moisture content are not the same, though both are important to monitor in cannabis for different reasons.

Moisture content refers to the total amount of water present in a cannabis sample, expressed as a percentage of its total weight. It helps determine the "dry weight" of the product and in cannabis is used in part to help calculate potency and cannabinoid and terpene percentages.

Cannabis flower typically has 6–15% moisture content (though a lower moisture content around 9% is best for producers who use automated pre-roll filling machines).

Water activity, on the other hand, measures the availability of what is called "free water" in the cannabis sample. It can influence microbial growth, stability and combustion. It is also a key contributor of product performance and customer satisfaction.

The Results

Using digital hygrometers, high quality hemp pre-rolls were stabilized at three different water activity levels: 0.45 aW, 0.65 aW and 0.85 aW. All three were analyzed using the laboratory’s smoking machine, a Combustion Smoke Analyzer SCS and all but the 0.85 aW pre-rolls (which could be breeding grounds for molds and microbials, making them unsafe for consumption) were also sent to smokers in airtight containers to be smoked as part of the survey. Survey participants were paid for their answers.

Affects of Cannabinoid Content

Using the smoking machines, the smoke from each of the differently dried pre-rolls was analyzed for cannabinoid content. Because the flower used for this study was a strain of high-quality hemp from The Hemp Mine called “FunDip,” the main cannabinoid was CBD. Other cannabinoids present in the flower and smoke were CBG, CBC and THC.

According to the results, pre-rolls with a water activity of 0.65 aW produced the highest cannabinoid concentration in the smoke, followed closely by the 0.45 aW pre-rolls.

The 0.85 aW pre-rolls, on the other hand, had cannabinoid contents of only 30% of the those in the 0.65 category.

Affects of Terpene Content

The smoke was also analyzed for terpene content. According to the study, the dominant terpenes in the FunDip flower are myrcene and alpha-pinene.

Testing for terpenes – which give cannabis its distinctive smell and flavor – generated similar results, with the 0.65 aW pre-rolls delivering the highest terpene content, with the scientists noting that it suggests “stronger water activity-dependent effects for terpene transfer” in the lower range, though the 0.85 aW pre-rolls again delivered lower terpene amounts overall.

It is interesting to note, however, that while the highest concentration of terpenes consistently came from the 0.65 aW samples, the scientists found “intriguing trends” in the individual terpene patterns.

For alpha-pinene, beta-pinene, myrcene and limonene, there was no statistically significant difference between 0.45 and 0.85 aW samples. Meanwhile, d-limonene was delivered at the highest concentration in 0.65 aW sample. Beta-carophyllene had similar concentrations at thew lower two water activities, but was significantly lower than the 0.85 aW sample.

“Based on these findings, the 0.65 aW samples are expected to deliver the most pronounced flavor profile due to their greater terpene yield,” the authors write.

Affects on Harshness

One of the things that makes the Science of Smokeability unique is the combination of lab data with that from a survey of pre-roll smokers.

Pre-roll smokers were sent pre-rolls in special containers to maintain their water activities and asked to give their opinions of the product. According to the results, “overall desirability slightly favored the 0.65 aW pre-rolls, though large variability rendered this distinction inconclusive.”

And while there was no statistical difference between aromatic and flavor profiles of the 0.45 and 0.65 aW pre-rolls, the 0.45 aW pre-rolls produced “a more irritating experience” for smokers, presumably a harsher smoke due to drier weed.

“These results suggest that water activity affects some components of the smoking experience, although individual preferences and perceptions may vary,” says the study.

Affects on Bottom Line

The study also delves into what moisture content and water activity can mean for the bottom line between flower with a water activity of 0.45 aW vs 0.65 aW, which corresponds to a moisture content of about 5% and 9%, respectively. According to the scientists, that difference comes out to about 18.14 grams per pound of flower.

“At an assumed market price of $1.50 per gram, this weight differential represents an estimated revenue loss of $27.20 per pound for material at the lower water weight,” they write.

Using their numbers, that represents about 4% of revenue per pound of flower, which would cost $672 at $1.50 per gram.

Final Thoughts on Phase I

The importance of a good cure cannot be overstated in the cannabis industry. Without a proper cure that brings the water activity and moisture content to the proper levels, even the finest genetics and the biggest buds can lose flavor and potency and become fast-burning and harsh-smoking.

And while some moisture can be returned to your flower, the original terpenes may be lost forever, rendering your smoke pretty, but flavorless.

Creating true high-quality pre-rolls means paying attention to the details at every step of your production process to maintain proper moisture levels of around 0.65 aW in your flower and in your finished product.

For that, we, of course, recommend the use of a humidor to ensure that your customers are never disappointed when they light up one of your pre-rolls.

Or, as the scientists put it:

“By optimizing water activity levels, it may be possible to enhance the delivery of desirable compounds, such as cannabinoids and terpenes, while minimizing the presence of potentially harmful elements.”