Wellness Watch

Solventless Flower Oil – The Luxury Concentrate

By Dr. Emily Earlenbaugh, PhD.

Rosin is a plant extract that does not contain solvents, allowing it to retain its quality and full terpene profile, which makes it a highly sought-after luxury.

As the high-end cannabis market continues to grow, dispensary owners and product manufactures alike seek to fill the growing niche for high-end, luxury cannabis products.

When it comes to concentrates, many people are looking to rosin to fill this luxury niche. But not all rosin is the same, and poorly processed rosin can range from a dark almost burnt tasting sap, to something that’s almost bright orange in color. A poor rosin experience can leave a bad taste in a consumer’s mouth, and discourage them from trying more in the future.

For dispensary operators looking to expand their luxury concentrates, skip the hair-straightener rosin and look for SFO. When it comes to concentrates, nothing is more luxurious than solventless flower oil (or SFO). Like most luxury items, SFO comes at a higher price point than the average gram of oil. But for those in the know, the price is well worth it.
What is so great about SFO?

Clean: Most concentrates are made using dangerous chemical solvents like butane or propane. This can leave behind toxic heavy metals. SFO is solventless. It is made using a modified Rosin process, which uses only low heat and pressure in the extraction process.

Made From Flowers: Safety is one huge bonus of the method, and I always suggest that patients and recreational users alike avoid concentrates made with solvents. But SFO is also special in that it is made directly from the flowers of the cannabis rather than the trim, hash, or kief, and the process preserves the flowers’ natural terpenes.
Feels Better: Terpenes are the compounds in cannabis that give it its smell and taste. Each strain has a unique smell and taste because of it’s terpenes. They also affect the feel of the strain. If you love the way sour diesel tastes and feels, but hate lemon haze, it’s probably because of the terpenes in each.
Terpenes can also modify the effects of THC, lessening some of its negative side effects like accelerated heart-rate, paranoia, dry mouth and mental confusion.
In most extraction processes, most of the flower’s natural terpenes are destroyed. If you have ever excitedly bought a concentrate of your favorite strain only to find that it doesn’t taste or feel like the flower, it is likely because the terpenes weren’t retained.  
Smells and Tastes Amazing: SFO has unprecedented natural terpene retention. This means it tastes incredible and feels like the flower it was made from.
Pressed at Low Temperatures: It’s important to note that not all Rosin is SFO. SFO is made using lower temperatures than the hair straightener and t-shirt press rosin that has flooded the market. High temperatures burn off the terpenes that make SFO so delicious. So, if you are making a purchase for your dispensary and you want a concentrate that will really knock your customer’s socks off, make sure the rosin is pressed at low temperatures and made from flower, not hash or kief.
Best Terpene Retention: When checking terpene analytics, beware of concentrates that have terpenes added back in. While we can isolate the terpenes we know about, we have only researched a subset of the terpenes in the cannabis plant. If we want to recreate the effect of a particular strain, we need to know all the compounds in it or the recipe won’t be right. Rosin with terpenes added back in tends to taste artificial and take on a brighter orange hue.
The most effective way of getting complex flavors and effects like those in the flower, is to preserve the compounds as they are in nature. That is exactly what SFO does.
If you are looking for that luxurious concentrate, SFO is bound to be a crowd pleaser with its potent, pleasant effects and clean, fragrant taste. Like many luxury items it is also rare, so finding a good supplier can be tricky.
For a great tasting SFO in CA, try out Fleurish Farm’s line of SFO. These Sonoma County rosin makers have perfected the art of terpene retention. Each flavorful option has a unique and complex aroma. And their terpene percentages are some of the highest around ranging from 3-9%.

About The Author


  1. Altruistic StrainHunter

    “Most concentrates are made using dangerous chemical solvents like butane or propane. This can leave behind toxic heavy metals. SFO is solventless.”

    If there is any chemical feat that changes butane and propane into heavy metals, please offer your source for this type of reaction to occur. This would be impossible per organic chemistry principles.

    Most concentrates are made using ice water and dry ice, then behind that is class 2 and 3 petrochemicals such as butane, propane, pentane and hexane, and behind that would be CO2 supercritical and after than would be good old organic ethanol.

    Anyone using a high grade 99% pure butane and a vacuum oven can purge their hashish so that residual tests come out to be below 10ppm and many extractors can consistently get 0ppm residual labs.

    Quality in, Quality out. If you want to implicate heavy metals in this article, you need to be transparent and say why. Sources or references. If you’re speaking to plant material leaching from the growing medium…..why implicate the solvent?

    1. Dr. Emily Earlenbaugh

      First, there is no chemical process that I know of to convert butane into heavy metals, and I certainly did not make that claim. Butane, as you note, is not 100% butane. It is the additives used and the metal in the cans themselves that can lead to heavy metal residue. You read about whats left over after purging here.. http://skunkpharmresearch.com/bho-mystery-oil/ … But putting additives (which may not all be able to be purged) aside, butane itself is a hydrocarbon with serious health risks. (See http://emedicine.medscape.com/article/821143-overview ). I agree that when pure butane is used, and the hash is properly purged, the resulting oil can be within health standards for human consumption according to current FDA regulations on butane intake. But we all have different standards for what we want to put into our bodies and some prefer to not inhale or ingest even small quantities of something with known toxic effects. Butane intake (as well as the intake of other hydrocarbons like propane or naphtha) can lead to a host of health problems (including death) in large quantities. For sensitive and immune compromised patients, these risks are magnified.

      In addition, not all hash makers use pure butane, or know how to purge properly, and poorly processed butane hash can have unsafe levels of butane itself, as well as whatever additives were used. If you live in a market that doesn’t have testing oversight, like California, you don’t know who is making your butane oil, what type of butane is used or what skill level the manufacturer has. Even in areas with required testing, like Colorado, small amounts of butane and the other additives are allowed. Some consumers even prefer poorly purged butane hash for potency. The truth is, butane is also a pharmacologically active chemical, which interacts with GABA(A) receptors leading to pain killing and euphoria inducing effects (See http://www.ncbi.nlm.nih.gov/pubmed/12459679 ). Patients themselves report having a harder time withdrawing from BHO dabs than other forms of cannabis, suggesting that they are forming a chemical dependence to the butane (See http://www.sciencedirect.com/science/article/pii/S0306460314001622 ).

      So, these are serious issues that patients and high-end recreational consumers are beginning to care about. As a patient consultant, I hear these worries from clients often. They want to play things as safe as possible. This type of purchasing trend is also seen with other health focused luxury items (such as organic food), where you see consumers paying increased prices for products that are organic, all natural or chemical free. The alternatives have all been deemed safe by the FDA but consumers who can pay for it prefer to keep the synthetic or known-to-be-toxic chemicals out of their food completely.

      1. Dave Struder

        First off I must say you folks are brilliant and impressive on knowledge. I was interested in sfo and rosin methods. One issue giving me pause on sfo is no trim Many elements are under the leaves. Thcv is one I am seeking to get 70% plus ThcV oil. Preferably 95% +. Realise pure is lab time too much $$$ for me and most, and hope 70% is not only attainable but as efficacious for the applications of copd helping stroke victims/neurogenesis! End type ll diabetes… and much more even. Why it is not as common as an ice cube defies any explanation I can offer.
        No one has any. Hmm. It is needed to save a life right now a friend of mine Marin California. Stage 4 copd inpatient… struggling for each breath.
        Still great to be in California but, let’s not get comfortable with just any old feco. We have the science and master growers oil maker godsends all! Just need this and all elements to have the complete medical remedy protocols known. We will all be and feel better. Grow for ThcV we are going to need tankers of it.

  2. David Watson

    Rosin can be nice but unless you grew the plant, you have zero control over if the plant was sprayed with pesticides or had mold before being made into rosin.
    The same with any extract, or even dry sift or water hash. I have made rosin for over 10 years, I do like it, but it is not as good as 99.9% resin heads that have been dry sifted. That is a fact.
    Rosin is more available then 99.9% dry sift, why is that? Because dry sift is the gold standard and is expensive to make because of the high quality and low yield.

  3. Doug

    Can you call it an oil product when it is a resin ?
    Some hash is made the same way, A warm pressurized fine straining cylinder could also refine it to a glossy goo.

    1. Dr. Emily Earlenbaugh

      Thanks for your comments David and Doug. Doug, The SFO process is different from the traditional rosin process and can creates a range of textures from thin shatter to a glossy goo. Oil simply refers to the essential oils of the cannabis plant that have been extracted.

      You are absolutely right, David, that high quality flower is needed for the rosin process. Fleurish Farms, for example, uses probiotically sun-grown outdoor from Wildcat Farms in Humboldt county. The flower is tested for mold and pesticides before processing, and the resulting concentrate is also tested for mold and pesticides. Whatever concentrates you purchase, make sure they come with lab results.

      When it comes to the difference between dry sift and rosin, I completely agree that most rosin is inferior. This is because most rosin makers use higher temperatures to pull out the most THC possible, and burn off the terpenes that balance the high and give the concentrate flavor. SFO by contrast, uses more powerful machinery to press at low temperatures and high pressure. This produces a flavorful oil with an exceptionally high natural terpene count. Comparing SFO with dry sift becomes more about preference. In my experience, dry sift is harder for most patients to work with for dabbing or pens. For this reason, it is not around much in shops, even though the method has been around forever. In my experience growers and wax makers love dry sift but there just isn’t much demand for it at the dispensary level.

  4. David Watson

    The reason it is not around is because it is harder to make and the yields are poor, but the quality is superior. You can easily make dab materials by pressing the resin for a few seconds, but it cant be used in the cartridge pens, you need something more liquid. If you ask the most experienced hash makers and extractors what they think is the highest quality, Rosin, water hash resin, dry sift resin, I know the answer will be dry sift. I think you are confusing easy use with the highest quality, they have nothing to do with each other. I do have a question for you, do you think that a SFO Rosin made from a 99.9% dry sift resin will be better then the dry sift? Why? Higher or better cannabinoid or terpene profile? Or just ease of consuming? Common sense tells me there must be at least a little bit of terpene loss during the Rosin making? Can you smell the process in the same room? That is the terpenes you are losing making the Rosin…..Test the terpene % in the dry sift and then in the Rosin, you will see the loss.

  5. Dr. Emily Earlenbaugh

    I absolutely believe that ease of use is one element of quality for cannabis patients and recreational users alike. It is certainly one aspect common to luxury items in general, they tend to be easier and more comfortable to use. Growers and manufacturers tend to have a different set of tastes than the consumers who go to dispensaries. But again, I have nothing against dry sift, it does have high terpene and cannabinoid ratings for sure. But I consistently hear patients dissatisfied with dry sift for ease of use. So for those looking to keep their dispensary customer base happy, I recommend SFO (testing with natural terpenes levels as high as 9%) as my pick for most luxurious concentrate.

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