Cannabis extraction debate: solvents versus solventless methods

Extraction consumers seeking high-quality cannabis products are becoming increasingly concerned about how their extracts are made.

Some methods use solvents that critics say can leave behind residual chemicals, while proponents counter that those residuals appear in miniscule and harmless amounts.

Other methods aim for maximum purity and forgo solvents entirely.

The global cannabis extracts market was valued at $4.3 billion in 2023, according to Grand View Research, a San Francisco-based market research and consulting firm.

It’s projected to grow at a 20% compound annual growth rate to reach $15.5 billion by 2030.

To ensure sustainability and consumer trust in the extraction market, marijuana businesses must pay attention to the process.

The healthiest cannabis extraction methods preserve the plant’s beneficial compounds while minimizing potential health risks.

Extraction using solvents

While there are several extraction methods, they essentially can be put into two categories: solvent-based and solventless.

Solvent-based extraction uses chemicals such as alcohol, carbon dioxide (CO₂), butane or other chemicals to dissolve trichomes, yielding high-potency extracts.

The solvent is then removed through vacuum evaporation, leaving a concentrated resin of cannabinoids and terpenes.

“You don’t want residual hydrocarbons – exposure to that is not safe,” said Lo Friesen, founder and CEO of Seattle-headquartered Heylo, a cannabis extraction and products company.

“People have developed post-processing steps – a solvent-removal process – to make sure they’re meeting the state’s requirements for how much residual solvent can be in the extract or finished product.”

Efficiency is another consideration, said Michael Sassano, founder and CEO of Somai Pharmaceuticals, a pharmaceutical manufacturer based in Portugal.

“Hydrocarbon is one of the most efficient extraction methods for cannabinoids and the terpenes compared to other methods,” Sassano said.

“You get higher yields, higher purity and more abundance of terpenes.”

Solventless extraction

Then there’s solventless extraction, where no chemicals are used.

Instead, solventless extraction relies on physical processes such as agitation, water, heat and pressure to separate trichomes from cannabis, resulting in a purer extract.

The process can be conducted manually or mechanically.

Darwin Millard, technical director of St. Louis-based compliance service Cannabis Safety & Quality, said the method used to consume marijuana also determines which process should be used to extract THC from marijuana.

Topicals are the lowest-risk cannabis product, followed by ingestion, Millard said. Inhalation is the highest risk.

“Consumer health is a layered concept,” Millard said. “Dabs are different from edibles.

“Your body does a really great job of digesting things and filtering out things that may not be good for you. The dose makes the poison.”

Friesen and Millard diverge on the solvent versus solventless debate.

Friesen is partial to the CO₂ extraction process, noting that the chemical compound kills yeast and mold.

“They call it the solventless solvent because it’s so clean,” she said. “When you remove your extract from the equipment, there’s no CO₂ left in the product.”

Millard, on the other hand, says solventless extraction is the healthiest – as long as the screens used for pressing are made from stainless steel rather than plastic.

“The industry is transitioning to stainless steel, which is great,” Millard said.

Nate Ferguson, co-founder and chief product officer at California-based Jetty Extracts, agrees that solventless is safer for consumption.

One solventless method is a rosin press that uses heat and pressure to create rosins.

“It’s like cold-pressed olive oil,” Ferguson said of using that method.

He also noted that it’s important to use high-quality marijuana for extraction.

Avoiding contaminants and maintaining safety

Beyond the extraction process, Ferguson said that some delivery devices can introduce contaminants into the oil.

“There can be dirty or heavy metals that leach into the oil, and there are bad ceramics that have a lot of lead,” Ferguson said.

Worker safety is another consideration for extraction companies, and most experts agree that solventless is the least likely to cause workplace injuries.

Using ethanol extraction or CO₂ or hydrocarbons exposes workers to the risk of explosions, but with advances in extraction equipment, it’s a rare occurrence, Sassano said.

But explosions still happen.

In January, two workers were injured in an explosion and fire at PharmaCann’s extraction facility in Stevensville, Maryland.

Butane and propane were being used in the company’s extraction process.

Margaret Jackson can be reached at margaret.jackson@mjbizdaily.com.