SOME TIME AROUND the mid-aughts, folks in the weed industry began to notice a shift in the market. Pot smokers were smoking less, and dabbing more—heating the plant’s oily extracts to inhale high concentrations of hallmark marijuana molecules like THC. Extracts, which go by names including shatter, batter, wax, dabs, and honey, weren’t just stronger than their plant-based starting materials. They were also more convenient to consume and easier to use discreetly. Elevated by its potency and portability, formerly-niche cannabis oil was going wide.
Today, extracts are more popular than ever. Dispensaries that use the cannabis database Leafly to organize their inventories have added 300,000 concentrate items to their offerings since the beginning of the year—an almost 600 percent increase over the same period last year. To keep up with demand, extraction labs and equipment manufacturers have developed increasingly sophisticated apparatuses to produce the stuff, and safer, higher-volume production methods.
These advances have afforded cannabis extracts—the intense highs of which have drawn misgivings from researchers and policymakers—a measure of legitimacy; last December, when California issued its initial round of business licenses for its legal marijuana market, the state gave its first temporary license to Moxie, a company known for its cannabis extracts. To distinguish itself in the Golden State’s new, booming legal market, it had to develop a wickedly efficient manufacturing pipeline for producing its sticky, icky wax.
Moxie specializes in a concentrate known colloquially as live resin. Unlike other forms of extract, which use dried and cured marijuana plants as a starting material, live resin begins its life as fresh crop. Harvest crews start by plucking buds from the plant’s stem (a process known as bucking), weighing them, and transferring them into vacuum-sealed bags. When the marijuana is harvested from an indoor facility, those bags go straight into a walk-in freezer cooled to -40 degrees Celsius. If it’s harvested from a farm, the bud goes in a cooler chilled with dry ice or liquid nitrogen. “Either way, within an hour or two of being harvested, you have a frozen solid biomass that’s measured out and ready for processing,” says Moxie CEO Jordan Lams.
Freezing at harvest has its benefits. For starters, it locks in the chemical profile of the fresh plant, helping to preserve flavors and smells that might otherwise be lost during the drying and curing process. But flavor preferences are subjective; the real advantages of frozen bud are economical.
The cannabis market is notoriously fickle: A strain that’s popular today might not be two months from now. But frozen weed can ride out such fluctuations. “You can run the stuff through an extraction process two years down the road, or reserve a strain for mixing it with another cultivar for some future production run,” Lams says. “And if something falls from grace, you can put it back in the freezer.”
When a given strain is in demand, Moxie adds it to its production schedule. Lab technicians pull frozen plant matter from the freezer and load it into an extraction system (“some people pack the material column tightly, some people pack it loose—this is where you get into the art of it and the nuance behind the process,” Lams says), where a hydrocarbon solvent like butane is used to separate the plant’s cannabinoids, which lend weed its psychoactive properties, and terpenes, which produce a strain’s characteristic flavors and smells.
Cannabis extraction via highly flammable hydrocarbons used to be a risky, small-scale affair—the kind of thing amateur chemists performed in their garages and backyards, with notoriously explosive consequences. People still do dangerous extractions, but legalization has encouraged safer production methods. Extraction labs like Moxie’s are OSHA-compliant, complete with negative pressure ventilation systems and spark-proof exhaust fans.
They’ve also scaled up: To produce cannabis extracts in high volumes, you need bigger equipment and more precise methods. That’s where systems like the X10—aka “The Judge”—come in. Designed by Michigan-based Precision Extraction, the imposing apparatus comprises a series of shiny steel tanks; a Borg-ian system of flexible metal hoses; and more dials, pumps, clamps, and valves than you can shake a vape pen at. The Judge can process 80 pounds of cannabis per day.
“It’s definitely the most impressive model Precision offers,” says Josh Mayo, who helped design the company’s original flagship model, the PX1, in 2016. These days, he’s Moxie’s chief technology officer.
The frozen weed goes into a tall, stainless steel column, while butane or propane gas is added to a solvent chamber, where a recirculating chiller cools and condenses the vapor into a liquid. The solvent then travels to the material column, where it saturates the cannabis and bonds with its cannabinoid, terpene, and lipid molecules. From there, the solvent moves into a third chamber, referred to as a dewaxing column, which is cooled to between -40 and -90 degrees Celsius. The temperature drop causes the lipids to solidify and separate from the solvent carrying the psychoactive molecules and smelly stuff. A filter traps the fatty solids as the liquid passes into a heated collection chamber.
There, most of the butane is boiled off. On a good run, a series of pistons recovers 99 percent of the evaporated solvent so it can make another loop through the system. And what remains in the collection chamber is the good stuff: a sticky, resinous substance with high concentrations of cannabinoids and terpenes.
Next comes a purifying step called degasification. Lab members pour the crude cannabis extract onto trays and load them into a vacuum oven, which sucks out residual hydrocarbons as they boil off. It can be a finicky process; terpenes, the fragrant organic molecules behind weed’s various aromatic properties, and possibly some psychoactive ones, are highly volatile, and many have boiling points close to the solvent’s.
The physical properties of the resulting extract can vary dramatically, depending on your starting material. Lams calls Blue Dream, a sativa-dominant hybrid crop hailing from California, a stable strain. “You run it through a hydrocarbon process and the extract that comes out is very hard, almost glass-like,” he says. “Whereas you run a strain like Gorilla Glue, or one with a higher or different terpenoid profile, and it’ll come out a lot more wet and fluid-like, so it pours thick like motor oil.”
Tweaks in processing can lead to extracts of different consistency, which take on texturally descriptive names like shatter, crumble, batter, and pull-and-snap, to be consumed via vape pen, a quartz honey bucket, a twaxed joint, or some other inscrutably named oleoresin-roasting rig. Budder, or batter, is formed by pouring extract into a Pyrex vessel and whipping it while applying heat. “It does evaporate some of the terpenes, but it also kind of integrates them into this creamy, frosting like-consistency,” Mayo says.
Regardless of the end product’s consistency, the resulting extract is loaded with concentrations of THC that can approach 90 percent. The terpene concentrations are less well characterized, though a 2017 study in the American Chemical Society’s ACS Omega cites unpublished findings that terpene contents can range between 0.1 and 34 percent.
That same study highlighted something else about cannabis extracts—namely how little we know about their relative safety. In a series of experiments, researchers led by Portland State University organic chemist Robert Strongin showed for the first time that myrcene, limonene, and linalool—three terpenes commonly present in cannabis—produce carcinogenic byproducts like methacrolein and benzene under simulated dabbing conditions.
“People consider dabbing a form of vaping, which they think makes it inherently safer than smoking,” Strongin says. “But comparing extracts to a joint is comparing apples and oranges.” He says people who claim vaping is easier on the lungs than smoking often note that the combustion associated with, say, a lit joint produces more harmful byproducts than the comparably low-temperature heat associated with vaping. (Sure enough, when I ask Mayo about the risks posed by dabbing, he says: “Inhaling anything is bad for you, but compared to the combustion you get when smoking flower, vaporizing is a much safer, pretty much harmless method of consuming cannabis.”)
But Strongin doesn’t dispute that hotter temperatures tend to produce more byproducts; indeed, his team showed that heating terpenes at lower temperatures produced fewer worrisome carcinogens. His point is that extracts contain compounds in dramatically different concentrations and compositions than you find in flower, which could yield dramatically different byproducts, as well.
And the thing is, nobody knows if the byproducts of concentrates vaporized at one temperature are more or less harmful than the byproducts of flower burned at a higher temperature, because, well, nobody’s studied it. Federal regulations still restrict scientists like Strongin from performing research on commercially available products. For now at least, even when you get your extract from an outfit as fastidious as Moxie, you’re dabbing in the dark.