Fulvic's Absolute Tek

Fulvic

Well-Known Member
For the past few years I'd been using the open tube method. My yields were always within 10-15% until I started using cooling baths and bumped my yields by nearly 10%. This one little tweak almost doubled my yields, so I decided it was time to look into changing up my technique.

Open tubes are great for a simple and quick extraction, but it's hard to fully saturate flowers/plant material without a repack and extra butane. It is a proven method, but TBH it's also a bit crude and I like progress.

The thermos technique chills butane below it's boiling point (30.2° F) so it remains in a liquid state and is easier to control. Cold butane is injected into a chilled thermal/vacuum flask (thermos) of plant material to soak for a prolonged period of time. No repacking or extra butane required. A more uniform and longer soak means a better yield.

When I first read about thermos extraction I ignored it, but I did some more research and came up with my own method. I yielded 23% my first run, I'm happy to say I've fully converted. My freezer is now fully stocked with butane.


Required Materials
  • flowers
  • 1000 mL Pyrex wide mouth Erlenmeyer flask with polypropylene screw cap
  • 2000 mL Pyrex heavy duty Griffin beaker
  • two standard size Pyrex measuring cups
  • butane (Colibri, Colton, David Ross, Dunhill, Lucienne, Newport, Sarome, Unilight)
  • 95-100% undenatured ethanol (16 fl oz)
  • acetone (32 fl oz)
  • dry ice (10 lbs)
  • protective gloves (natural or latex only)
  • a stove top
  • a freezer
  • a pot
  • a drill
  • 1/8" and 3/16” drill bits
  • a rubber band
  • No. 4 unbleached coffee filters
  • parchment baking cups
  • two stage vacuum pump and chamber
  • magnetic stirring plate and PTFE stir bar
Safety Precautions*
  • ABSOLUTELY NO SMOKING
  • always have a fire extinguisher at the ready
  • always setup outside, never spray or evaporate butane indoors
  • keep the butane away from any/all possible sources of ignition
  • take precautionary measures to avoid static discharge, no synthetic clothing
  • immediately wipe up any accidental spills or spray, change clothing if necessary.
  • never use fans to pull, only to push butane vapors away
Prep

1. Leave butane in the freezer for at least 4 hours; it needs to maintain a temperature well below 30.2° F in order to remain in a liquid state.


2. Break apart flowers to 1/4" pieces and load up the Erlenmeyer flask, be sure to drop a PTFE stir bar in first. Screw on the polypropylene cap and let the flask and Griffin beaker chill in the freezer for 2 hours.
This time I stowed the flask and beaker in the freezer for 2 hours before starting the cooling bath. The extra step helps to prevent possible fracture by avoiding the extreme temperature swing.​


3. Remove the the flask from the freezer, place it in the beaker so it’s sitting on the bottom and unscrew the cap.

4. Crush up the dry ice and pour enough into the beaker to bury at least half of the flask. Pour acetone into the beaker in 50 mL increments until a slushy/slurry consistency is reached.


5. Drill a 1/8" hole in the polypropylene screw cap for butane injection, and a 3/16” hole for ventilation.


6. Take one unbleached No. 4 coffee filter, place it in the top of Pyrex measuring cup #1 and secure with a rubber band.


7. Using Pyrex measuring cup #2, measure 1.5-2 mL of 95% undenatured ethanol per gram of flowers and pour it into the pot.


The next four steps are by far the most dangerous, please refer to the Safety Precautions*

Soak

8. Screw the cap onto the flask, put on protective gloves and get butane from the freezer. Without removing the flask from the cooling bath, carefully inject enough butane to submerge the flowers. Turn on the magnetic stirring plate, let it run at 750 rpm and monitor discoloration.
Butane is fractionally soluble in water. If it gets cold enough (below 32 °F) any water that is dissolved with butane turns to ice. During the cooling bath soak, due to extreme temperatures (-109.3 °F), water acquired by butane from moisture that may be left in the flowers (including chlorophyll) will freeze up for easy filtering.


9. After 30 minutes (or once desired consistency is reached) turn off the stirring plate. Leave the flask in the cooling bath for another 15 minutes to ensure all the water has fully crystallized.

I left the flask submerged for another 15 minutes with the stirring plate off, to ensure all water had fully crystallized. I ended up with what looked like more ice than last run, though admittedly I should have measured before the adaptation. Differences (if at all) in the end product are negligible, but I want to ensure there is positively no water in my absolutes. If nothing else, the extra 15 minutes give me peace of mind.​

10. At the end of the cooling bath, put on protective gloves and carefully remove the flask from the cooling bath. Immediately unscrew the cap and pour the solution into measuring cup #1 through the secured coffee filter. Remove the filter and squeeze any extra solution out of the flowers.

Prior to disposal, be sure the filter/flowers have adequately dried to ensure all residual butane has evaporated. It’s an easy way to avoid inadvertently introducing butane vapors indoors.

Immediately following the cooling bath, I filtered out the ice so it wouldn't melt in the butane and reintroduce water to the solution. To do this, I needed two measuring cups: Measuring cup #1 is used to filter ice and plant material from butane. Measuring cup #2 is used to pour hot ethanol into measuring cup #1. I could bring the pot outside, but I'm paranoid about static discharge so I'm trying to use as little metal as possible.​


11. Go inside, be sure not bring a draft of butane vapor into the house; walk around to a separate entrance. Place the pot of ethanol on the stove and bring it to a boil (172.4 °F). Remove from heat, pour the ethanol back into measuring cup #2 and bring it outside.
Wash

12. Monitor measuring cup #1. As soon as one third of the butane has been reduced, immediately (but carefully) pour the hot ethanol from measuring cup #2 into measuring cup #1. Once all activity and bubbling has ceased, all butane has been fully purged.

It's important to remember the order of oil transfer: Erlenmeyer flask > measuring cup #1 > parchment baking cups. Due to adhesion, any surface the solution touches will be left with a film of solvent which will quickly evaporate and leave essential oils stuck to that surface. The fewer surfaces the solution comes in contact with, the greater the return.​
When using non-polar solvents to extract essential oils, non-polar fats and waxes are extracted too. Ethanol is polar and washes essential oils clean, leaving non-polar fats and waxes in suspension for easy filtering. The hot ethanol will help the cold butane exceed 30.2° F and boil off. Essential oils and phenolic resins remain dissolved in the ethanol and so, are unable to solidify and trap any butane gas in bubbles.


13. Stow the measuring cup in the freezer for at least 4 hours to help ensure all of the fats and waxes have coagulated.

During the cold ethanol precipitation wash, 4 hours in an average household freezer is sufficient time for all fats/waxes to coagulate and separate from the ethanol. There was just as much precipitate after only 4 hours in the freezer from this last run; 18 hours was overkill to say the least...​

14. Take the measuring cup out of the freezer, lay out parchment baking cups and get another unbleached coffee filter. Filter the precipitated fats and waxes out of the ethanol solution into the baking cups, 15 mL each.

I found 1.5-2 mL of ethanol per gram of starting material to be a perfect ratio for my applications. I ran 32 grams of flowers, yielding a little over 7 grams in return. I used 60 mL of ethanol, divided it up into four baking cups at 15 mL each and ended up with 1.7 grams of absolute a cup.​

Purge

15. Place four baking cups in the vacuum chamber, turn on the pump and evacuate down to -29.9 in. Hg. After the ethanol completely boils off, continue to pull until there is no visible reaction. Once there is absolutely no activity, close the pressure gauge valve, disconnect the hose from the pump and turn it off.

If there is excess water dissolved during extraction, multiple pulls can sometimes be beneficial when vacuum purging. Using a cooling bath freezes up any water dissolved with the butane, so heating to viscosity and pulling a second time is unnecessary. This time I pulled to -29.9 in Hg only once, and held it until the ethanol had completely boiled off. Again, the differences are negligible but at the very least it gives me peace of mind knowing I'm evaporating only what is necessary.​
Remove the baking cups and enjoy!
 

Abysmal Vapor

Saturnine in my mind
:) Nice tech.. but see this.. http://fuckcombustion.com/threads/bho-extraction-on-goes-boom.4570/
Also plz add some pics.. and purity comment/evaluation. More yield doesn't mean purer product, for example longer soaks gives worse quality oil. Other than that your tech for sure can be done with home supplies.. but i don't think it is safe or simple enough..
You need acetone,dry ice,ethanol,and butane
so i need some visual proof and quality comments to make me use all this stuff.. cuz with either one of them alone extraction can be made + (i am not fan of canned butane.. (just cut open a finished butane can of the purest you got and you will see the gum residue on the sides )
 
Abysmal Vapor,
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Fulvic

Well-Known Member
Thanks for the link, I've seen that picture and a few that are similar. I don't encourage anyone to attempt this technique without exercising extreme caution, safety must be priority number one.

I especially don't encourage anyone to put boiling butane in their freezer...

I haven't had the oil tested, but it's the cleanest BHO I've ever made or tried. My tek yields a far purer final product than most BHO extraction techniques. I never suggested it was simple. You don't have to try it.
 

Abysmal Vapor

Saturnine in my mind
Yep it is too complicated for me.. I'll just stick to my regular ethanol quick wash, you can do 2 quick washes on same herb and get nice yields although the second is of a bit poorer quality and different chemcal ratios.. IME is a bit more stony,but idont mind that since it does not makes me cough and tastes pristine :p.
 
Abysmal Vapor,

t-dub

Vapor Sloth
Fulvic, I don't even make these types of concentrates but I loved your post simply from a scientific pov. Your lab notes remind me of me :) thanks for sharing.
 
t-dub,

Fulvic

Well-Known Member
Thanks t-dub. I did my third run last night and I finally got everything dialed in, so I thought I would share - three's a charm. It is a bit complex, but it's overall a safer process with a cleaner end product.
 
Fulvic,

weedemon

enthusiast
Fantastic post my man! :)

I need one of these vaccum setups i keep hearing about I would love to get off using as much heat to do my purge.

" Because of the ethanol, terpene phenolic resins were not able to solidify and/or trap any butane gas in bubbles" - totally man, this is why i like the ethanol extraction after. I have found i lose some flavour from doing the ethanol extraction though. you you agree?

I have a question for you.

I have never used dry ice before. why acetone to turn it into a slurry?
 
weedemon,

Fulvic

Well-Known Member
Unlike water, acetone won't freeze up when added to dry ice. Other solvents (ethanol, hexane, butane) would also work, but aren't as readily available or as cheap as acetone. The slurry of dry ice and acetone is called a cooling bath, and maintains a temperature of -78°C. Cooling baths have multiple advantages, one in this instance being you can use plant material immediately after harvest.

Butane is fractionally soluble in water. If it gets cold enough (below 32 °F) any water that is dissolved with butane turns to ice. During the cooling bath soak, due to the extreme temperatures (-109.3 °F), any water acquired by the butane from moisture that may be left in the buds and/or trim (including chlorophyll) will freeze up for easy filtering.
 
Fulvic,
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Bouldorado

Well-Known Member
:) Nice tech.. but see this.. http://fuckcombustion.com/threads/bho-extraction-on-goes-boom.4570/
Also plz add some pics.. and purity comment/evaluation. More yield doesn't mean purer product, for example longer soaks gives worse quality oil. Other than that your tech for sure can be done with home supplies.. but i don't think it is safe or simple enough..
You need acetone,dry ice,ethanol,and butane so i need some visual proof and quality comments to make me use all this stuff.. cuz with either one of them alone extraction can be made + (i am not fan of canned butane.. (just cut open a finished butane can of the purest you got and you will see the gum residue on the sides )

I just did this with an old can of vector I found in the recyclables. Tore it open, and despite my expectations, it was perfectly clean inside. When you run your finger on the inside, it feels like clean metal; no sticky residue at all. Did you actually try cutting a can yourself, or simply relay information heard elsewhere? maybe different brands are dirtier, but the interior of this vector can is clean enough to eat off of.
 
Great thread! What speed do you set your magnetic stir plate to? Also, do you use a 1" PTFE stir bar w/ spin bar or without? Regardless, thanks for the info.
 
BernsteinTerpentin,

Fulvic

Well-Known Member
750 rpm for 30 minutes.

I use a 1 1/8" octagonal stir bar with a pivot ring.

No worries, thanks for the interest... :)
 
Fulvic,

SpiralArchitect

? & beyond
Thanks for this.
Great writeup. It sounds like you have some sort of scientific background?
One day I'd love to attempt absolute, but for now, crude open extractions do the trick.

Any pictures?
 
SpiralArchitect,

Bouldorado

Well-Known Member
Thanks for this.
Great writeup. It sounds like you have some sort of scientific background?
One day I'd love to attempt absolute, but for now, crude open extractions do the trick.

Any pictures?


You can still make an absolute from a tube extraction. The end result is no different than if you were to make the intiial bho from the soak method. Simply dissolve the bho into ethanol, winterize, filter, and evaporate.
 

SpiralArchitect

? & beyond
Well aware.
A simple typo on my part misconceived what I may have intended to say; 'I'd love to try a closed extraction' but thanks for your profound insight.
 
SpiralArchitect,
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