Soxhlet Extractor: Old Equipment, New Technique

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? 

Enter
Sam the Mushroom Man, the owner of Mindfull Mycology, a medicinal mushroom extract company using Soxhlet extractors to make all their extracts. Take it away, Sam!

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.

soxhlet extractor
The Soxhlet extractor hooked up to a cooler of ice water to keep cold water cycling over the condensor.

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 understand 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. 

soxhlet extractor
The siphon arm slowly filling with Reishi extract

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 finished it recently! Go Check it out!👇

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 week later with lifelong friends and a passion for mushroom cultivation. 

Since 2020 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

soxhlet extractor

Responses

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  1. I want to learn this! How much is that glass fabulous tool? And what are the step-by-step lessons I can purchase or watch video or how do you recommend to teach so I’m a pro too in my little bubble?

  2. I would love to learn more. I am a professional lab tech in the legal cannabis arena and looking to expand my knowledge.

  3. Hi Sam
    I do double extraction mushroom,but I want to learn to use the Soxhlet to do the extraction.Can you tell me the size of the soxhlet that you show in the picture and the parts that I need to make work?
    Thanks
    Rick

  4. Hi,
    I have a couple questions around this technique, and I’m wondering where is the best place to ask them? But the main question is, once I have extracted using a soxhlet extraction, how do I test the potency of what I have extracted? Specifically mg/ml I think.

    Thank you so much for the great post.

    1. You got to send it to a lab for more info on your potency which is pretty expensiveeee. We’re in the works for a video on how to work with the soxhlet, stay tuned!

  5. Is this method can be used to finally make the mushroom oil tincture? I saw the liquid tinctures most often have alcohol in it, but some have just mushroom extract mixed with mct or hemp oil. How to make mushroom extract that dissolves in oil?

    1. Hey Lukasz! This method will not work with oils since it’s reliant on the evaporation of the solvent. Alcohol is a crucial part in extracting nonwater soluble compounds. If you don’t want alcohol present, you can quite easily cook it off after the extraction

  6. Would love to learn more about this topic and how to best use this tool. Can we expect a video any time soon? Thank you!

  7. Wonderful synopsis,
    Thank you so much for the turn on! Definitely looking forward to a video of technique and using this properly.

  8. Thank you so much for sharing. Very cool! I’m curious; from what I can see, it looks like both your soxhlet AND round bottom flask are 1000ml. In my mind, it would make sense to have a larger rbf or a smaller soxlet. I’m a hobbyist, not an expert. 🙂

    1. Generally, for better extractions you want a bigger soxhlet and a smaller flask. I currently have a 1000ml flask and a 500ml soxhlet and its just not cutting it for me….

  9. That is bad ass! I want one. I’ve been making dual extracted tinctures for around 4 years. But, its a bit tedious and time consuming. I’m crazy busy and want the very best product I can make. Please tell me where I might purchase one of these.
    Thx mates, Jody Foster
    MOMS Mushrooms
    #mushroomfantasies2023

  10. Are there different types of these? Which exact one are you holding in the picture? And where’s the best source to get one. Thx mate. #mushroomfantasies2023

  11. This is an amazing resource! I found stumbled in searching for the technique. So glad you put this up. I play around with traditional herbal medicine (for fun, not to treat anyone!). Unsurprisingly, medical researchers have shown that some old folk remedies worked and why, so
    I’m trying to create some recipes based on folk medicine and validated by modern research. I have been TRYING and TRYING to figure out how to do a Soxhlet extraction. I was pretty sure it didn’t mean put some plants and vodka in a mason jar and leave it for 6 weeks. I saw pictures of the machinery, but couldn’t find anywhere that explained it in plain English. So I basically have to build a still and engineer a safe heat source… Yay!

    If you ever want a free comfrey balm I will totally send one. Not as fun as shrooms, sorry.

    If you have any other practical tips for a using this Frankenstein contraption I’d love a follow up article!

  12. Hey Sam, do you do 10lb with the same batch of solvent? I’ve just run 500g through mine and wondering if there is a risk in denaturing the compounds of the extract by using the same solvent with so many passes, I.e a lot of time that the solvent is spent with heat on it. Cheers

  13. Hi there, totally intrigued by this and hope to find an affordable one second hand soon. Have a question: what’s the exact benefit of vaporizing the solvent and then re-condensing to liquid compared to just running cycles without doing the vaporizing process.

  14. Little known? So SOXHLET extractor is a common piece of laboratory equipment I’ve been using for 40 years it’s not a rare item it’s used regularly in Labs all around the world

  15. Hello, thank you for the article and sharing your knowledge!

    I am interested in a consultation, can you tell me how to connect in that way?

  16. Great article thank you. Do you think you would still need hot water extraction for some mushrooms? Or do you think the repeated extraction would get all the compounds? Thank you

  17. Hi Sam,

    What is the ideal dried mushroom to liquid extract ratio? And how do I get the water extract for this process? Do i use a soxhlet with water or regular boiling for 3/4 hours?

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