CannabisTech had an opportunity to speak with Ben Britton, Co-Founder and Lead Engineer at Pure Pressure, along with Eric Vlosky, Director of Marketing. Ben and Eric gave us insight into the essential elements required to ensure repeatable and scalable rosin production.

Listen to the conversation.

The Basics of Rosin Extraction

Rosin extraction relies on temperature and pressure to extract oils without the use of solvents. Essentially, the moisture within the flower helps decrease viscosity so the oils can flow better. According to the folks over at Pure Pressure, one of the leading producers of new-wave rosin extractors on the market; 

“Rosin is the cannabis oil and concentrate that is created when you apply heat and pressure to cannabis product. The process liquefies and extrudes the trichomes and cannabinoids out of the material that you are pressing. It really is the most simple extraction method.”

The trichome heads rupture to produce a shatter, butter, or oil containing the desired compounds like cannabinoids and terpenes.

Rosin extraction is a relatively recent innovation within the marijuana industry, and techniques are continually evolving through experimentation. So why does a perfect extraction require a period of experimentation?

Each element in the extraction process exerts considerable influence over the makeup and quality of the final product. 

The following ideas on controlling rosin extraction are based on the use of a commercial extractor.  The more primitive the device, the less control one has over the elements. Understanding the role that each of the involved factors plays can direct a more educated experimentation process.

Humidity

Flower contains oils that are extracted using heat, pressure, and filtration.  The heat liquefies the oils, the pressure mobilizes the oil and the filter material separates the oil from the plant matter.  If the relative humidity of the flower is too dry, then the plant matter will absorb the oils when they are liquefied and yields will decrease.  Maintaining the relative humidity of the flower around 60% allows you to benefit from the hydrophobic nature of oil and prevents it from soaking into the plant material.  

Temperature

The temperature of the process influences the consistency of the extraction. This important aspect of the rosin process can change the viscosity of the natural cannabis oils, allowing for extraction from the plant material. This means pressing butter at the lower end of the temperature spectrum, anywhere between 140 to 180 F. Some industry experts recommend between 200 to 230 F for flowers. A shattery consistency happens around 220F.  Producers need to be wary of relying on higher temperatures during pressing as it can sometimes damage important medicinal compounds. Some terpenes are especially sensitive to high temperatures, anything above 230F might increase their volatility in the air. Once exposed, the terpenes may simply evaporate. 

Pressure

More pressure does not equal more oil. Pressure is one of the main ingredients in the rosin extraction process, but higher is not always better. As a general rule, most extractions only require 550 to 1,000 PSI.

Some producers report increasing the PSI into the thousands, but the oil suffers. High PSI eventually leads to undesirable compounds, for example, plant lipids contaminating the end product. Eric Vlosky at Pure Pressure has a different opinion;

“Our cylinders are oilless and maintenance free, and they are pneumatic. Which is the key thing….You don’t need nearly as much pressure as a lot of our competitors are saying … They are just using high-pressure hydraulic cylinders because that’s the cheap and easy way to create a press.”

Depending on the type of material being pressed, different-sized micron bags are used for proper filtration. Rosin filtration bags help maintain consistency between pressing for optimal rosin results

Strain & Plant Quality

The quality of cannabis going into the rosin extraction process always affects the quality of cannabis oil produced. But even beyond the underlying quality concerns, other characteristics of the original cannabis can influence the final consistency, color, and cannabinoid content of the rosin oil. For example, the fresher the marijuana flower the clearer the rosin.

As cannabis dries out, it eventually begins to oxidize, leading to a much darker oil extraction. Final consistency also relies on the strain involved. The unique mixture of terpenes and cannabinoids found in each strain actually has a dramatic impact on final consistency. 

Time

The type of extractor definitively influences the time requirement, but time is an essential component in and of itself. The longer the pressing time, the higher the risk of incorporating less desirable compounds into the final oil. Even with a complete understanding of how temperature, pressure, and humidity affect rosin extraction, the nuances of each strain (and theoretically each harvest) can affect the final outcome. 

Rosin extraction is a science. Using the best equipment, and controlling all the elements involved, rosin extraction quality can be replicated. A typical yield is between 15% to 30% percent with most high-quality flower clustering in the teens or low 20s. Rosin extraction, despite its complications, is one of the leading clean technologies today in the cannabis industry.