Over the past few years a little known extraction apparatus invented in 1879 known as a Soxhlet extractor has taken the medicinal mushroom extract industry by storm. But what is this fancy looking piece of glass, how does it work and why are people so excited about its application to medicinal—and psychedelic—mushroom extraction?
Saturation: The Soxhlet Extractor Sauce
Howdy, folks! It’s Sam the Soxhlet Extractor Man here to give you the lowdown on the Soxhlet’s subtleties.
So, what’s all this hoopla about after all? Well, a Soxhlet extractor offers extractors like me a few important benefits.
For one, using a Soxhlet extractor allows you to cycle the solvent through the dried mushrooms numerous times during each extraction process. This constant contact between the heated solvent and the mushrooms increases the extraction’s efficiency compared to the classic homestyle dual extract process.
Second, because the solvent percolates through the entirety of the mushroom and then returns to the boiling flask without any mushroom matter—other than the medicinal compounds—we can reuse a solvent multiple times while cycling in fresh mushroom powder. At Mindfull Mycology, this allows us to use 10lbs of fresh mushrooms for every 1 liter of extract, a concentration level 2-8 times more potent than our competitors.
Third, because the Soxhlet extractor is a closed system, we’re able to heat 190 proof alcohol to its boiling point without danger, thereby allowing us to efficiently extract medicinal compounds that are insoluble in water like the highly desired triterpenes, phenolic compounds and fatty acids. Reishi mushrooms, for example, contain more than 100 triterpenes (e.g. Ganoderic acids) known for their medicinal qualities. Our Soxhlet extractor pulls most of these lipids out, causing our Reishi extracts to appear opaque and almost milk-like.
Simply put, what we’re saying is that the unique attributes of a Soxhlet extractor allow us to use a smaller amount of solvent to extract a larger amount of mushrooms than in a homestyle process. And more mushrooms into each bottle = more medicinal compounds in each dose.
Compared to homestyle extracts—like the one’s your local mushroom farmer may make with leftover mushrooms—you can expect Mindfull Mycology’s products to have more medicinal compounds per milliliter of extract.
There are more reasons why the Soxhlet extraction process is leveling up the medicinal mushroom industry but by now you probably get the point: medicinal mushroom products extracted with a Soxhlet extractor are superior to products extracted using the homestyle dual extract or triple extract methodology.
So, next time you’re looking for a high quality medicinal mushroom extract, your best bet is to buy one from a company extracting 100% mushroom fruit bodies using a Soxhlet extractor and incorporating both a water and alcohol extraction step—known as a dual extract—into their final product. On that note, I think I know of a company…
Sizing Up the Soxhlet Extractor
Now that you udnerstand why a Soxhlet is such a great piece of equipment, let’s give you the low down by breaking down the Soxhlet extractor into its basic components.
Beginning at the bottom of the glassware, we first encounter what’s known as a boiling flask. This flask, usually composed of borosilicate glass, is where we place our solvent, that is, the liquid which will extract and dissolve the compounds we’re looking to capture during our extraction process. In the extraction of medicinal mushrooms, water and/or high-proof alcohol—we use 190 proof USDA-certified organic cane alcohol at Mindfull Mycology—are the most commonly used solvents.
Can you guess what the boiling flask does? Ding, ding, ding…it boils your solvent! At Mindfull Mycology, we use a heating mantle like the one found here, though budget DIY options using heating plates and sand exist, too.
Moving vertically up the glassware to the top of the boiling flask, we’ll next introduce ourselves to the main Soxhlet extractor component: the extraction chamber. It’s in this chamber where we place our dehydrated and powderized medicinal mushroom fruit bodies like Reishi (Ganoderma lucidum), Lion’s Mane (Hericium erinaceus), Cordyceps (Cordyceps militaris) and Turkey Tail (Trametes versicolor). Usually, a thimble is placed inside the extraction chamber to hold the medicinal mushroom matter—I prefer 25 micron rosin press bags—and keep it from interfering with another part of the extraction chamber known as the siphon arm. But we’ll get back to that piece of the puzzle later.
By now, your eyes might be starting to get a little glossy. But truthfully, all I’ve really covered is that a Soxhlet extractor has a flask for holding the solvent and a tube above it for holding the mushrooms. Pretty simple, right? Let’s push on.
Along the side of the extraction chamber, you see two tubes: the distillation arm and the aforementioned siphon arm. If you’ve ever made moonshine—Mindfull Mycology is located in the Appalachian Mountains of Georgia, after all—you know this already, but the distillation arm is simply a glass tube that captures the vapors rising from your solvent as it boils in the flask.
As the solvent vapors rise into the distillation arm, it travels upwards until reaching the end of the distillation arm, which terminates at the top of the extraction chamber. Here, you’ll see that a series of glass spirals—or hollow bulbs—encased in a hollow, cylindrical glass vessel sit atop the extraction chamber. This is a condenser with an inlet at the top for cold water and an outlet at the bottom to drain the cold water. During a run of the Soxhlet extractor, a water pump lifts water through a latex or silicone tube to the top of the condenser where it then cascades down the condenser tubes and exits at the outlet. The condenser’s job is simple: recondense your solvent vapors into a liquid.
Now, let’s revisit the siphon arm. In some ways, the siphon arm is where the real Soxhlet extractor magic happens. The siphon arm is a glass tube nearly identical to the distillation arm in location and composition with one important difference; while the distillation arm connects the top of the boiling flask to the top of the extraction chamber, the siphon arm connects the top of the boiling flask to the bottom of the extraction chamber.
Let’s imagine our solvent has been boiling, the vapors have been condensing and percolating through our mushrooms and the extraction chamber has been filling with this recondensed, percolated solvent. Eventually, the extraction chamber will be completely full of solvent, right? Well, the siphon arm is there to prevent this from happening.
Positioned outside of the extraction chamber and about 2/3rds of the height of the extraction chamber, the siphon arm is what allows us to drain our extraction chamber and return the solvent to the boiling flask for another boil, evaporation, condensation and percolation cycle. Its mechanism is simple: as more and more solvent fills the extraction chamber, it also begins to fill the siphon tube. Once the solvent reaches a level equal to the top of the siphon arm, it crests the 180 degree bend and tumbles down the other side of the siphon arm like a cart full of teenagers screaming down the main drop of a roller coaster. So, where does this descent lead? Right back into the boiling flask.
Let’s take all those words and “condense” them into one line: a Soxhlet extractor is used to boil a solvent to a vapor, recondense the solvent into a liquid, percolate the solvent over the medicinal mushrooms, return the solvent back into the boiling flask, and then cycle the solvent through that same process over and over again until the extraction is finished.
Woof, we hope—and are proud of you if—you hung around for all that.
So there you have it: a real rundown on the Soxhlet extractor. Truth be told, there aren’t many good videos out there explaining how to use one properly and what tips and tricks to take into account so you don’t burn through a half pound of Turkey Tail mushrooms and coat the inside of your boiling flask with a thin layer of impossible to clean tar…not that we know of anyone who has done something like that.
So, maybe a high-quality video is the next thing this beautiful rig needs as it reaches its tentacles deeper into the medicinal mushroom scene? We’ll let you know when we put that out there. Until then, take your extracts people!
About the Author
Sam is a mycophile, award-winning journalist and small business owner from the United States who arrived at the Fungi Academy one midsummer’s day in 2019 and left six weeks later with lifelong friends and a passion for mushroom cultivation.
In the past three years, he’s started a medicinal mushroom extract company, cultivated and foraged over 20 species of gourmet and medicinal mushrooms, and returned to the Fungi Academy to teach his techniques to students.