With the growing interest in solventless extraction methods, people are beginning to look to rosin as an alternative to butane or propane extracted concentrates. As patient consultant, I often hear consumers, who worry about the dangers of ingesting these toxic solvents, asking for an alternative that they can feel confident is free of other substances. As someone who oversees the health and safety guidelines for Fleurish Farms, a company known for it’s high-grade rosin production, I also often get asked about best practices for pressing rosin.
Whether you are a consumer or dispensary operator looking for the best product, or a manufacturer looking to keep your craft to the highest standards, it’s important to understand the quality markers for high-grade rosin.
Clean, Flavorful Flower
High quality rosin begins with high quality flower. At Fleurish Farms they currently use pro-biotically grown flower from the master grower at Wildcat Farms in Humboldt, CA. Before pressing they make sure that the flower has been tested for mold and pesticides. We’ve found that the most flavorful rosin comes from pressing the whole flowers, rather than trim or kief, and refer to this specific type of rosin as “Solventless Flower Oil” (or SFO).
Low Temperature & High Pressure
The rosin method, uses heat and pressure to extract the cannabis oil, so one of the biggest variables with rosin quality has to do with the temperature and pressure it was pressed at. For SFO, it is important to use high pressure and low temperatures (below the boiling point). Of course, this type of high pressure pressing requires a custom industrial press. Those using hair-straighteners and tee-shirt presses will not be able to achieve these kinds of results.
The press and SFO method developed at Fleurish Farms allows for unprecedented levels of terpene retention (with results as high as 9%). Many extraction methods strip the oil of it’s natural terpenes, or burn them off. Hair straightener methods, for example require higher temperatures and burn off many of the delicate monoterpenes responsible for the taste and feel of a particular strain. The temperatures used on Fleurish Farm’s SFO however, remains low enough to retain the plant’s natural terpenes.
Terpene retention is incredibly important to maintaining a high quality cannabis extract for many reasons. For one, the terpenes are what makes the cannabis plant taste and smell like it does. So, when the terpenes are retained the result is an oil that tastes and smells like the strain it was made from.
I tried the 9% terpene SFO that Fleurish Farms had entered in the Emerald Cup and the oil tasted like the essence of the original flower (Cherry Limeade, an amazing strain from Aficionado); pure cherry lime deliciousness without any taste of plant matter.
Strain Specific Experience
In addition to the taste, the terpenes also alter the way the oil makes you feel. Recent studies show that much of the differences patients notice between different strains of cannabis come down to their terpenes. So, if you like the way a particular strain feels, and want to get that experience through a concentrate, you need to find one that preserves the natural terpenes from the original flower. Terpenes also modify the effects of THC and can help negate some of the negative side effects that patients experience like rapid heart rate, paranoia, dry mouth and mental confusion.
The most effective way of getting complex flavors and effects like those in the flower, is to preserve the terpenes as they are in nature. This is exactly what you get with the high pressure, low temperature SFO method. The terpenes in rosin cure with age in much the same way they do in flower. As long as they are stored properly (like flower) there are no additional shelf life concerns.