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making extract with a soxhlet apparatus

ive seen several people talking about making pepper extract, so i thought id share how i go about it.

here's the soxhlet apparatus. it consists of a soxhlet, the bit in the middle. a condenser, the bit on the top. and the flask, the bit on the bottom.
here is what happens, once the flask is heated vapors travel up through the soxhlets sidearm up into the condenser, which condenses the vapors back into a liquid wherein they fall back into the soxhlet. the soxhlet is designed such that it will fill up with solvent and then drain itself almost completely back into the flask. it accomplishes this by starting a siphon once it begins to overflow through the small u shaped siphon tube you see on the side, this siphon will not break until it sucks air so naturally it empties almost completely. this process will cycle pretty much indefinitely as long as you provide heat and cool water to the condensor.

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heres the pepper we are extracting, dried bih jolokia pods, i have hundreds of them, id probably have more if the plant didnt catch a virus :eek: or atleast what i think was a virus.

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anyway, i tossed a bunch of these into a blender untill they were reduced to flakes

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these flakes were packed into a glass thimble, which is basically a container with frited glass disk on the bottom that allows solvent to drain through. you absolutly do not need a thimble, alot of people just stuff a bit of loose cotton or glass wool into the base of the siphon tube. keep in mind tho that w/e you are extracting will float, so you need to get a plug of cotton on top of w/e you are extracting so that it will not float around

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and now we fill the flask... with 200ml of n hexane, good and cheep non polar solvent. we use hexane because its non polar, a non polar substance is not misicible into water hence it will not extract water soluble stuff like chlorophyll and w/e else is is in plant tissue. im not the person to teach you why things are polar and why things are not, but i can tell you that it has to do with molecules dipole moment.


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and now we apply heat! hexane boils quickly, at 70c. notice those little black bits on the bottom? those are boiling chips, i use them to get nice even safe boils. theres a phenomenon called "bumping" wherein you heat a liquid past its boiling point and it explosivly boils over at some trigger... like a bump. if you are lucky you just get a boil over into your distillate, if you are unlucky you get burned. you see 'bump flasks' on some apparatuses to stop contain this.

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soxhlet filling up...

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almost full...

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to many photos!
 
and 20min later we drain! subsequent cycles take only 10 minutes.

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after a dozen cycles or so we are left with this, pretty orange as you can see. we remove this from the heating mantle, and assemble the distillation apparatus!

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so this is the distillation apparatus. this thing consists of an claison adapter, also called a still head... a condensor the bit in the middle, and a reciever with a vacuum takeoff, thats angled bit with the nipple bit off to the side.

a word on condensers. there are tons of them , the one you see here is pretty common.. its called a liebig, basically a tube jacked with another water filled tube. liebigs are cheep but not the most efficient, on really high volume stills like on a rotary evaporator, you will see coil type condensers that have a much larger surface area, and can deal with alot more than a liebig.

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here you can see the hexane starting to come over, it is very cloudy for some reason, i had never seen this before, but it didnt seem to effect the end product.

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we stop the distillation beffore we run it dry. believe me, you do not want to heat capsacin oleoresin, its pretty damn volatile and it will ruin you. coughing crying burning etc.

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we wash this out of the flask though a filter into a beaker. i actually lost a lot of extract inside the coffe filter i used, id reccomend using a loose piece of cotton pushed into a long stem funnel in the future.

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and let evaporate in a very well ventilated area until...

boom.
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nice gooey sticky and very hot oleoresin

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this stuff has a bit of water in it, when removing the condenser some sweated water made it down into the receiving flask, so this stuff is not as dry as it could be. the image in my avatar is oleoresin that is considerably more tar like, tho it was also chilled in my fridge for a while before i got around to taking its picture.

11.4grams of flaked bih jolokia yielded .9-1g of extract

a word on safety, id like to point out that i do not wear goggles(you should) i do not use gloves(you should)... and i dont watch the apparatus 100% of the time(you should), i do have a fire extinguisher tho, and you should absolutely have one too when working with any hot solvents! especially indoors...
this is more of a, do as i say not as i do type of thing thing... id really advise that you dont be as caviler as me. you should really study up on how to run glassware, as well as proper safety and handling practices when working around glassware before try anything like this. i recommend the safety bits in voguels practical organic chemistry, that books like 200$ i think, but its pretty popular... so you can find it in the more unscrupulous areas of the internet.
 
how long to get 2 ounces of extract how much hexane does it take?
2 ounces of extract is ALOT, i would think it would take a few pounds of dried pods to get that much. but as far as how long it would take, it all depends on how large of a soxhlet you use. the one here is 200ml, they range from like 10ml to 12 liters. if you tried this with a soxhlet like mine... it would probably take many many extraction. as to how much hexane, it depends on the size of soxhlet you choose to use.
 
Thanks for posting this mate, i may have to get alk mad scientist like and try this out!
Although instead of hexane i will use 190 proof moonshine. :0
 
STICKY !!!! this is a great tutorial for people who want to make some good Capsaicin that can be added to sauces and as emergency mosquito bite balm;
http://www.thehotpepper.com/topic/26701-peppers-are-good-for-you/page__p__533609__fromsearch__1#entry533609

Excellent article and well done how-to-do it. :woohoo:

congratulations and thank you for sharing it :beer:

Balac
 
Really great and informative post! Never seen anything like this. Thanks for sharing the details.
Is your name Walter White?*




(Walter White = "Breaking Bad's" genius chemist. :halo: )
 
The distillate was initially cloudy because it contained water. This is called an azeotrope. Your dried pods must have contained a little water. Hexane is highly flammable and a neurotoxin. That oily residue will contain all kinds of toxic crap.. Don't try this at home, kids.
 
hexane boils like 30 degrees lower than water, how could it form an azeotrope? and yea hexane is flamable, and toxic, but only from prolonged exposures of like 400ppm... thats like co2 concentrations in natural air.
i dont think anyone took issue with hexane untill those chinise workers were almost killed, they need osha!
and what makes you think that the oleoresin would contain enough hexane to harm you? many many food oils are extracted with n-hexane.

edit: not trying to be defensive or anything, id just like to hear you elaborate on these things a little.
 
The bp difference doesn't matter. There are lots of examples of azeotropic solvent mixtures with bigger differences in bp than this. For the record, the constant boiling azeotrope between hexane and water is an approx 95:5 ratio and boils at 62deg C, about 6 deg lower than hexane. When the mixture cools, the two solvents separate, which you see as cloudiness. Check out the wiki page on azeotropes for more info, and this link for specific info on the water-hexane azeotrope.

http://www.shaman-australis.com/~auxin/solvent1.html

Re: flammability of hexane. This stuff burns in air extremely violently. Furthermore, if you're unlucky enough to get the right composition of air, hexane vapor and a spark from some appliance in your house, you will have an explosion. Trust me, I have seen this happen and it is terrifying.

Re: toxicity of hexane. There is no safe level of exposure. That's why people in the chemical industry in the west have been avoiding it for decades and replacing it with less toxic solvents such as cyclohexane.

Re:my comment about the oily residue. I am assuming that you are using hexane that has not been redistilled to high purity. In this case you have higher boiling hydrocarbons present. Benzene and related aromatics are common impurities in commercial hexane. They are present in tiny amounts. Removing the hexane by distillation as you did would concentrate them up.

Sorry about my serious tone here. I am an expert in this field and concerned for your safety and for the safety of others who may attempt to duplicate your expt.
 
The bp difference doesn't matter. There are lots of examples of azeotropic solvent mixtures with bigger differences in bp than this. For the record, the constant boiling azeotrope between hexane and water is an approx 95:5 ratio and boils at 62deg C, about 6 deg lower than hexane. When the mixture cools, the two solvents separate, which you see as cloudiness. Check out the wiki page on azeotropes for more info, and this link for specific info on the water-hexane azeotrope.

http://www.shaman-au...n/solvent1.html

Re: flammability of hexane. This stuff burns in air extremely violently. Furthermore, if you're unlucky enough to get the right composition of air, hexane vapor and a spark from some appliance in your house, you will have an explosion. Trust me, I have seen this happen and it is terrifying.

Re: toxicity of hexane. There is no safe level of exposure. That's why people in the chemical industry in the west have been avoiding it for decades and replacing it with less toxic solvents such as cyclohexane.

Re:my comment about the oily residue. I am assuming that you are using hexane that has not been redistilled to high purity. In this case you have higher boiling hydrocarbons present. Benzene and related aromatics are common impurities in commercial hexane. They are present in tiny amounts. Removing the hexane by distillation as you did would concentrate them up.

Sorry about my serious tone here. I am an expert in this field and concerned for your safety and for the safety of others who may attempt to duplicate your expt.

Hey thanks for replying, i actually was not aware that azeotrope concept was so involved. my engineering degree plan only required g chem, so my chemistry game is limited.

concentrating the benzene is something honestly i hadnt considered. the msds listed benzene as >10ppm. i wonder how much of that ends up remaining in the oleoresin.

what do you do btw?
 
It's hard to know for sure what other compounds you will have in the residue. We've analysed the residues from several commercial solvents and found them to vary a lot in terms of purity and content from batch to batch. Sometimes the analysed residue doesn't match the specs on the bottle. I would not trust what is written on a bottle of solvent if I was planning to ingest something that had been in contact with it. I'm a professor of organic chemistry. I also have chilli plants in my back yard!
 
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