Been running quite a bit of thermos BHO lately and noticed GK doesn't have a tutorial on this old extraction technique. I use this method for larger runs used in cooking. Thermos BHO can also be used for regular dabbing or vacuumed to produce high quality smoking product. We are replacing a Dewar flask with a large open mouth thermos to create a long soak extraction using butane and cannabis flowers. This can be done with fresh or cured material. Fresh material will create a clearer extraction with more of the original flavors and nuances of the original plant. Cured material and leaves produces a darker product that is generally more hashy tasting. To start you'll need the following: - A large open mouth stainless steal thermos - Sufficient high quality butane to fill the thermos 2/3 full - cannabis - small food vac (not necessary) - tin or jar cover to use as a discharge plate - Pyrex dish - paper coffee filters - 15 micron filter - 95% alcohol (everclear in my case) - 1/8" drill bit - vinyl electrical tape - Ice - rock salt - small cooler First, as in all BHO extractions, all evaporating and release of BHO must be done outdoors. Any photos below showing otherwise are simply demonstrations of a technique and NO release of BHO was done indoors. Let's start with the thermos. Take the screw in stopper and cut the very top off leaving the threads and seal intact. Drill two opposing 1/8" holes 1/4" from the outside wall. Break or cut the cannabis into small pieces. Do not grind or pulverize your starting material. Lightly pack until the thermos is 1/2-2/3 full. Screw in the adapted stopper. Cut two strips of electrical tape to cover the holes in the stopper. Using your food vac, extract as much air as possible from the thermos. The tape over the holes acts as a one way purge valve allowing the thermos to retain vacuum. Pop the thermos into the freezer for several hours. The intent is to reduce the amount of moisture available in the plant material by freezing. Vacuum simply reduces the atmospheric RH in the thermos during this process thereby reducing condensation and accompanying ice. Moisture brings with it unwanted by products such as chlorophyll. (The vacuum step is not essential. The freezing step is essential)) The tape after vacuum. Take your frozen thermos out of the freezer and put into your small cooler. Pack ice and rock salt around the thermos, 1 pound salt to 3 pounds ice. This will bring the temp of your solution down to between -7C and -15C which aids in extending wash time. Drill a 1/8 hole in the canning lid and remove the screw in stopper from the thermos. Placing the lid over the thermos mouth eject the butane into the thermos. A 68oz thermos 2/3 full of material typically requires 5-300ml cans of butane. Replace the screw in stopper, with the tape removed. Let the mixture soak for 2-2.5 hours in a well ventilated area OUTDOORS. Gather up the pyrex dish, coffee filter and/or 15 micron filter. I filter the extraction BHO into a stainless cup because it holds my filter. You can filter directly into your purge dish if you choose. Pour the liquid BHO from the thermos, through the filter, into your catch vessel. Cover (or not...I don't like dust in my BHO) and leave to evaporate, OUTDOORS. You'll end up with a familiar looking goo. Dissolve this BHO goo using 95% alcohol. Everclear, 190 proof grape alcohol, or, in a pinch 91% iso. Pour the liquid in a jar and freeze for 24 hours. Filter once more to remove waxes and other settled contaminants. Allow to evaporate and you'll have a nicely polished absolute oil to smoke or use in recipes. At this point I either apply vacuum to remove any excess moisture or apply low heat to create shatter for toking. Or, more typically, pour whatever cooking oil I want to infuse directly into the dish and dissolve the extract then save.
Good stuff. One question though, what's the purpose of the canning lid? Why not just use the plastic top with one hole taped off?
Great tutorial Res... May I ask what the advantage of a 2-2.5 hr soak provides? Is there an advantage vs how I jus pass the butane through a tube? Great looking oil though.... What was the strain?
Thanks BB. Think that was a Lemonberry. Don't really have an answer. I know a shorter soak doesn't give a full yield of BHO...and that's about it. Skunky probably has a better reason as to why. The advantage is the ability to do larger runs. Pass through columns are good to about 3" in diameter. After that you need to move to a bath technique. The quantity of material that can be processed is only limited by Dewar flask (thermos) size and amount of butane available. You ever wonder how large scale edible production happens? They use large scale butane extraction similar to what I did in the tutorial. Except instead of a thermos they use vats and recapture the butane. Simple answer? Because the butane cans won't fit down in the well on my thermos. If they would fit, yours would be the perfect way to do it PD asssit:
Simply because of how cold butane is and the lack of closed pressurized systems. Just like water dissolves sugars and salts and such much better when warm than cold same with butane. Except tanes specific heat, boiling and evaporation rates are much different. Can't really use warm tane being aerosolized or presureized. Even if you could it'd evaporate way too fast. So one way is either extend the exposure time to solvent or add and maintain a constant pressure to a closed system. Makes for a more efficient extraction. Think again about water. If you have a column filled with sugar and run a smaller volume of water through it to will dissolve less sugar than placing the sugar directly into the same volume of water. Things don't dissolve immediately and dissolution rate is a function of temperature and pressure since volume of the vessel is constant.
There ya go. :redbong: Thanks skunky, nice to know the "why's" in a process. The real benefit for me is not having to repack multiple cylinders for pass through extractions when doing what for me are larger runs. Also figured that since any H2O in the plant material is locked up as ice it never has a chance to add contaminants. Didn't realized it may do a better job of extracting more cannabinoids or THC.
Well makes sense to me too... But I'm getting much better than 10% return on pass through attempts. My column holds 200 grams of dry material. I just ran 38 grams of trim and finished with 4.5 grams of BHO...
You gots a bigger tube than me.:icon_redface: :wtf?: One thing I found, when running more than an ounce or two through a tube, is that the tane tends to channel through the material. It always takes an extra wash (or two) to get a good return. At least for this mortal any ways. asssit:
After each can of tane I pull the stopper... And the steel wool.... Mixx up the material... Lightly repack it... Put the steel wool back.... The stopper... Then run the next can... I'm thinking that helps eliminate channeling... Oh and the tube is very sweet indeed... And reasonable seeing its surgical stainless and has a tripod that sits outside the collection dish I paid $114.99 including shipping and five 50 micron stainless screens and stainless clamp. They have multiple tube configurations where there are 2 or 3 tubes tied together so you can run 600 grams at once...
I'm going to switch to this method for my next run. I spend waaaaaay too much time packing weed into a mag light tube. I employ the funnel / ramrod method. I'm getting good returns too but I think they could be better. Also, to illustrate Resin's point about the difference in fresh material vs cured. The dark stuff was 3 week dry trim, the light stuff 3 days dry. The light stuff crumbles and tastes like sweet lemons. The dark stuff tastes like a burlap sack and locks the lungs to a considerable extent. Note these waxes were not made with the above method.
This is interesting stuff. I'm saving for a closed loop. I only recently came across this technique and only heard a brief explanation. Thanks for the step by step. I ran some fresh material the other night. 48 grams wet so probably equates to about 11 or 12 grams of dry material. Yielded 1.6 grams. Roughly 13%-14% I'd really like to hit that 25% mark on return though. What kind of yields are you pulling with this method RR?
A consistent 15%+ on dry weight using a 2 hour soak. Never heard of anyone hitting over 20%. Didn't even think it was doable.
It's possible from what I have been told. With good starting material. Nug run. I've seen reputable cats claiming 25% on Ice Water Extraction. 15% isn't too bad though. Speaking of 25% I could have sworn I read a thread on here from MrGj where he ran 1 Oz of dry trim and pulled 7 grams from it. Unless I read it wrong that would be 25%
Once again...things beyond my mortal capabilities. I remember Gj shocking the shit outta me with some big BHO numbers awhile back. Ice water or bubble bag yields always confuse me. Shit, if a guy runs a loose screen he could pull 30%. Me, I'm happy with 15%. Winterizing costs me a little and I don't always do it (though one really should). I've had the occasional 8% yield too. But it's never been offset to the positive by an equally large amount. For me to get a consistent mid teens in % requires starting material just a notch below marketable bud. I look at hashing as what to do with the huge bags of shit you've got left over after those little bags go out the door. With that in mind, I suppose I'll never see the numbers other folks talk about because I won't sacrifice top quality flowers.
I think the same way about hash, it's not the reason I do what I do so I don't use the bud for hash either. I'm happy with my bubble returns. I would like to try to grind and dry sift some buds just to see if it's worth the hype, from what I understand you get a smaller return but the best product.
I have a tumbler that's been sitting still for over a year. Kief is good and fun and all, but for me even less convenient to smoke and transport than wax. Pressing into hash is tricky to get right - easy to over-press and wind up with a rock. But if you're gonna collect dry kief, a tumbler is the way to go.
