Key Takeaways
- David Sandelman, COO of Canachold, built his vapor pressure control technology from a Vermont inn and restaurant, where local cheesemakers were struggling with inconsistent aging room conditions – a problem that ultimately led to the development of the Vapor Troll system.
- Sandelman argues that relative humidity is not a controllable variable, as it is the byproduct of temperature and vapor pressure – the two components operators must actually manage independently to achieve stable, repeatable post-harvest results.
- Side-by-side analytics show that conventional drying methods rupture 25 to 30% of cannabis trichome heads, while Vapor Troll technology reduces that figure to just 1 to 2%, resulting in measurably higher terpene retention.
- Operators who overdry cannabis flower to avoid mold risk are walking away from 5 to 7% of top-line revenue – a loss Canachold says its technology eliminates by bringing flower to equilibrium at the target water activity and holding it there without active intervention.
- Beyond cannabis, Sandelman identified hops and tea as the next significant post-harvest applications for the technology, and described AI-assisted environmental tuning as a near-term direction for the platform.
David Sandelman Built a Post-Harvest Platform From a Cheese Cave Problem
David Sandelman, COO of Canachold, did not set out to work in cannabis. Speaking on the Vertical Farming Podcast, Sandelman traced the origin of the company's Vapor Troll technology to his time running a Vermont inn and restaurant, where a commitment to local sourcing brought him into close contact with regional cheesemakers who were losing the battle against their own aging rooms.
The problem, Sandelman explained, was that traditional European cheeses were developed in specific geological environments – aged in caves where temperature and moisture content were extraordinarily stable. Vermont has no caves to speak of. Attempting to recreate those conditions in a retrofitted room meant contending with fluctuating humidity and temperature swings that undermined the aging process. The solution was not to control humidity directly, but to understand what humidity actually is: the combined product of air temperature and vapor pressure.
That insight became the foundation of everything Sandelman has built since.
Why Relative Humidity Cannot Be Directly Controlled
A central argument Sandelman makes – one that distinguishes Canachold's approach from most of the indoor ag industry – is that relative humidity is not a variable operators can meaningfully dial up or down. It is a derived measurement, produced by two underlying components: air temperature and moisture content (measured as vapor pressure or dew point). Change either one, and relative humidity shifts automatically.
“Relative humidity is the same thing as a bank loan,” Sandelman said. “You get a monthly payment, and if you want to increase or decrease your monthly payment, there's no dial to turn. You've got to change the term, the interest, or the principal. Change any one of those three and your monthly payment changes.”
The consequence in practice is that facilities running air conditioners alongside dehumidifiers are often caught in a cycle where the two systems counteract each other – one drying and warming, the other cooling and drying – producing what appears to be a stable relative humidity reading while the underlying vapor pressure swings significantly. For plants, those swings matter: vapor pressure differential (VPD) at the leaf surface directly affects transpiration rate and nutrient uptake.
The Trichome Problem in Cannabis Drying
When Sandelman first applied Vapor Troll technology to cannabis, early feedback from growers was immediately positive. To understand why, the team commissioned side-by-side analytics comparing conventional drying – typically around 60 degrees Fahrenheit at 60% relative humidity – against controlled vapor pressure drying. The results were striking: conventional methods caused trichome head rupture rates of 25 to 30%, while Vapor Troll reduced that to 1 to 2%.
Trichomes are the small glandular structures on cannabis flowers where THC, CBD, and terpenes are produced and stored. When those heads rupture during drying, the volatile compounds they contain are lost. Higher intact trichome counts translate directly to higher terpene retention and, in Sandelman's framing, a more expressive, consistent final product.
Whether the rupturing in conventional systems is caused by the mechanical stress of fluctuating vapor pressure – the trichome wall is only two cell layers thick – or by the inability of those walls to harden properly under unstable conditions remains an open question Sandelman says the company is still investigating.
David Sandelman's Case for Water Activity Over Percent Moisture
A recurring theme in Sandelman's work is the gap between the metrics cannabis operators use and the metrics that actually predict product stability. The industry largely relies on percent moisture as its measure of dryness. Sandelman argues this is the wrong unit entirely.
Water activity – a measure of the ratio of bound to unbound water in a product – is the standard used in food, pharmaceutical, and archival preservation. At a water activity of 0.6, molds and microbes cannot access enough free water to survive. That threshold applies equally to salami, hard cheese, and cannabis flower. The cannabis industry, Sandelman notes, is behind by decades in adopting a unit of measure that other sectors take for granted.
“The food industry has used water activity for decades. The pharmaceutical industry for decades. Even museums look at water activity to make sure their rare documents aren't devoured by mold. Yet in the cannabis world, people are still talking about percent moisture,” Sandelman said.
From Drying to Curing to Storage: Eliminating the Guesswork
Conventional cannabis post-harvest requires operators to make a judgment call about when to halt the drying process and move flower into sealed containers for curing. That call has historically been made by touch and instinct – stem snap, texture, experience. Get it wrong in either direction and the result is either mold from residual unbound water or overdried flower that sacrifices yield and quality.
Canachold's system removes that decision point. By holding vapor pressure constant, flower dries to equilibrium with its environment and stays there without continuing to lose moisture. Dry, cure, and storage become a single uninterrupted continuum rather than three distinct manual steps – what Sandelman describes as “sous vide for weed.”
Operators currently overdrying to protect against mold – a common practice – are typically drying to a water activity of around 0.5 instead of 0.6. That difference represents 5 to 7% of top-line revenue in lost flower weight, on costs that have already been fully absorbed.
David Sandelman on What Comes Next: Hops, Tea, and AI
At the Indoor Ag-Con conference, Sandelman said conversations quickly moved beyond cannabis to adjacent crops where post-harvest vapor pressure control could deliver similar benefits. Hops was the application he flagged as most promising: the hop plant is closely related to cannabis, shares a rich terpene profile, and is currently dried using heat – a process that volatilizes terpenes at relatively low temperatures. Sandelman is actively seeking a brewing partner willing to run a controlled trial.
Tea was another area Sandelman identified as ripe for exploration. All major tea varieties – white, green, and black – come from the same plant, with the differences created entirely through post-harvest processing steps that have remained largely unchanged for centuries.
On the technology roadmap, Sandelman described AI-assisted environmental control as a logical next layer – using plant feedback signals to tune VPD dynamically rather than relying on static setpoints. He was careful to note that sensor accuracy remains a precondition: “garbage in, garbage out.” And he acknowledged that experienced growers, who can read plant stress visually and adjust accordingly, remain essential partners in training any automated system.
Canachold offers the Vapor Troll system at commercial scale, beginning at around 160 to 180 pounds per unit, as well as a home-grow unit called Cool Cure designed for harvests of up to roughly two and a half pounds. The company is developing intermediate products aimed at social clubs and larger home growers. More information and technical white papers are available at Canachold.com.
