First Run BHO, Problems with yield and potency

Hey there,

I’m pretty new to the bho scene and I have recently built up my own extraction column and also made my first passes. Before I have done that, I really read a lot on this page.

So my passes hadn’t been too bad ive made 1 batch with about 100g of trim and also tried two frozen extractions.
First some facts about my column.
I have a 2” column which fits about 50g of nugs, leading to a 6x6” collecting chamber. I do not recover my solvent. I have a 4CFM 2 stage vacuum pump from best value vacs. And I have only used butane this time. That’s pretty much it.
Now I will let you know how I have done it and will ask some questions which I couldn’t find in the threads, Sorry if it is somewhere and I haven’t found it I really searched a lot.

So first I chilled my Column with dry ice and Isopropyl, I have also chilled my collecting chamber just the solvent was not chilled. Then I filled my column with the dry trim set it under vacuum and filled the column with gas. Then I had let it sit for about 10 minutes and opened my ball valve to the collecting chamber. The next step was the filtration, I have a bottle top with 0,2 my. After filtering I let evaporate the butane on a heating mat at about 25-30°C (77-86f)
From 100g trim I got about 6g extract so that yield for just sugar leafs was not to bad I guess.

That was the first extraction, the second one started with the frozen nugs. Ive done the same procedure as before. First time ive let it set for about 15 minutes. After evaporation I recognized that I had very less yield. So I made a second run on this material and let it set for another 30-45 minutes. The color was different and after evaporating I have seen that the second pass was way more “oilie” than the first pass, so I guess the second pass has been more Terps? Might it that be?
I don`t exactly know the weight from the plant because i straight froze it after chopping but I also dried some and they all had about 30-40 g. My yield was about 1,5g of oil from that one.

Third extraction I have done the same again just let it set in the column for over an hour.
Again about 30-40g.

Then I started purging. I do not have an extra vac chamber for purging I just use my collecting chamber. I put a blind cap on the part which is normally attached to the column. Then I put my collecting chamber on the heat mat and pull vacuum. Every 30 mins I opened and whipped my oil. I cannot adjust the vacuum so I just pulled full vacuum and was about -0,9 bar (-6750mm hg).

What I have seen when I opened my chamber after purging that there was a gas in the chamber which has not been butane. So is my pump really to strong and pulls the terpenes out of the extract?

With the trim I tried to make shatter which worked really great, ive read that I should use dried material for shatter due to there are not as much terps present as is fresh frozen material. The shatter is not the most clear its a bit dark but the consistency is really as I wanted, you can really break or pull and snap it at room temperature. Only the potency is missing somehow I guess. Compared to my buds my extracts really suck... The fresh frozen extract has crumbled, now its kind a waxy crumble. It tastes really good like limonene but again the potency is just not the best.

So now a few questions from my side:

What do you think is the problem with the low yield? Only butane use or did I let it set to short in the column to extract everything?
My plants had been frozen for about 2 months and some ice crystals had been on the buds before I have extracted them might that be a problem?
Is there a difference between the butane you can buy at bbv as a solvent and the butane/propane which is for camping grillers?

Is my pump too big for my chamber, how much vacuum should I pull while purging?

All in all I have learned a lot with my first passes. I know where I can upgrade my extractor and also really confident for my next runs. I hope I have not forgotten anything :wink:

And already thank you for your information and help. If you don`t understand something just ask me, sorry English is not my main language so I’m not sure if everything is understandable.

how much solvent did you run during your extraction? It sounds like you should be getting more. There is a chance you did have ice covering the trichomes which can prevent the solvent from reaching the inside, resulting in lower yields.

You mentioned freezing the buds beforehand, are they fresh and not dried yet, or are they dry at this point? Running non-dry flower will yield considerably less because you can’t fit as much in the tube as when it was dry and half the size.

There is a difference in gasses to an extent. I wouldn’t advise using camping propane as there are cleaner options out there. I use puretane from the cans personally.

I would recommend investing in a solvent tank so you can recycle your gas. Your system is more robust than usual open blast systems, so you can really increase your safety and solvent loss by recycling it. Additionally having a fully closed loop will let you distill your solvent before running it to remove the impurities from the gas that are in the tank itself. Even puretane has residuals that need to be distilled out. Once you distill gas once, you’ll never run dirty gas again, it changes everything.

Thanks for the answer.

My column is 5,08cm x 50cm (2‘‘x19“)
So the volume should be about 3,2 (7,1lb) liters if i calculated right.

I had nothing to weigh my gastank unfortunately so i dont exactly know how much gas it was but i always made 2 passes pulled vac and filled the whole column. In the collecting chamber i had on the thumb about 1,2 liters (2,64lb).

That with the ice around the nugs is pretty sure a thing then because i had it frozen and in those 2 months it thawed 2 times.
How big do you prefer the nugs to be?

The buds are not dry. I cut them off and put them right into my freezer.

Thanks for the info with the propane.

I already thought about that and thats why i built my extractor like this but right now im have to less money to afford a recovery pump. Or can i also just let it evaporate in the collecting chamber and attach a tube to the gastank which sits in dry ice? So through temperature differences its changing to the gas tank?

Does it make a big difference in the taste?
This time i used the camping gas but therefore i tried to purge it longer so i hope its not affecting the product to much.

Its hard to get pure good quality chemicals here in my country. In America its way cheaper unfortunately they don’t send it to my country.

Are you doing this inside? You’re whole process seems dangerous. You know a recovery tank for something that small can be had for incredibly cheap.

I just feel like you planned to do it right and gave up worrying about it

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No i would never open blast or like this semi closed inside.

Yeah what kind of recovery tank like a normal gas bottle with a cap to let gas in and out?
Or like my collecting chamber ? I‘ve seen so many different ones. And the parts for bho are really hard to get here. I had to buy some things from a brewery website and from wine distilling sites. The parts i bought from america are good but the delivery was 300$ and as im an apprentice i dont earn too much.

I really want to do it as right as possible i even want to send my samples to an analytic lab to see how much solvent is left etc.

Since im a passionate smoker since a few years. I have chronically back pain due to a motocross accident. Smoking bong. With buds is nice but long term i think its not the best for the lungs so i would prefer oil and distillates.

If i have finished my apprenticeship as chemical progress technician i would really like to work with cannabis. Unfortunately in my Country the extract scene isnt even a little bit here… i just know a company like tilray which has a company in Germany but those companies are so big i would like to be in a smaller one the see the whole process and not just operate one machine…

[Recovery tank ]
( listed at grainger. Not sure if they exist by you, but It was a good company that isn’t extraction related and is everywhere in America at least.

Look for an hvac supply house near you and call around.

You need something with the two valves. One with a dip tube for supply, and one without for return.

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You can get the same tank at Ferguson for half the price if there isn’t a grainger in the area

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I’m running a 1.5" x 18" column, very close to your size column. I can generally pack around 100-120g of dry material in the tube. If you’re freezing and thawing, it will likely cause some ice buildup that will prevent your extraction from pulling everything it can. You can always run the material again warm and see if anything comes back. It will likely have a good bit of waxes in there, but some don’t mind that, or can clean it up afterwards by winterizing.

Personally when I run my tube that size, I get around 15g of extract when it’s all said and done.

If you’re only running enough butane to fill the column, you will not be extracting everything. I like to run a lot of gas through the first time to ensure I got everything. For my column, I run about 5lbs of butane through. It’s a bit overkill I’m sure, but it works great for me. I recycle my gas too, so it’s not losing anything.

Since you’re not drying beforehand, your yields will be much lower than if you dried, because you can only fit like 50% of the material in there when it’s still wet.

Did you weigh the material going into the tube? that’s a good way to calculate your extraction efficiency.

I don’t generally use bigger nice nugs for extraction… Since I grow my own material I use the popcorn buds and trim exclusively. My bud size is like 1/4" diameter on average at the biggest.

Propane in itself is a good solvent, but since it’s more popular in cooking/camping, getting clean propane is generally more difficult. Not to mention the pressures will be much higher working with propane, and when you get a recovery tank to reuse your solvent, it will be more difficult to recover due to the lower boiling point. A lot of canned butane will actually have around 20% propane in it for added can pressure. Propane usually tends to pull more terps and will result in a lighter color naturally. That said, straight N-butane isn’t going to produce a bad extract and is safer and easier to use due to the lower pressures and higher boiling point. I personally like a blend, but lately I’ve been using 100% n-butane.

For a small system you don’t really need a pump unless you want to recover that way. More moving parts means more potential for broken equipment. I run a passive system without pumps and use temp differentials to move the gas where I want it. As you stated, dry ice and lines to another vessel are really all you need to recover passively.

Even so, you can recover without dry ice, it just takes longer. I typically do it this way, just ice water and salt to get it cold. It’s no where near as good/fast as dry ice but it gets the job done for me.

If you’re not distilling your gas, yes it will change the taste. Before I was distilling, my extract always had this same rubber taste that was in the background. Once I did my first distillation and smelled the crap in the pot, I immediately recognized the smell and realized I had been contaminating my product for years. Since I started distilling, my extract tastes like it should and doesn’t have any off tastes.

You can get almost any canned butane and distill it. You will need a recovery tank, but you will run the system as you would during an extraction, but with your column empty. Once you recover the gas to your recovery vessel, the can lubricants and other contaminants will stay in your collection pot and you can clean it out when you’re done. Your recovery tank will have fresh clean gas in it. If the gas is really dirty you’ll need to do this a few times but typically the first pass is sufficient.

Another gem I learned on here is when distilling, don’t get your temps too hot… If you stay under 80-85F it will prevent the heavier hydrocarbons from recovering with your butane leading to higher purity gas.


In my tube the maximum was about 60g of trim then it was full and a little pressed.
I havent weight the frozen plants but dried it should have been about 30-40g.
Do you let the solvent through the column or do you let the gas in for a time and then open the next valve to the recovery chamber? If you do for how long?

And thanks for the tip with the recovery and distilling, it cool that this is also working without a pump. and im really looking forward to use destilled gas. I think i know that you mean with the taste, all 3 of my extracts have a kind of same “undertaste”

and do you think that my 4cfm pump is to big for my 6x6 Chamber?
How much vacuum do you pull during puring?

Thanks for your infos its really helping me a lot and motivating me to my next passes.

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Just dry your material before hand. Dont freeze it. Put your material in first and vacuum down your application. Keep vacuuming (not your recovery pump) while you making your dry ice slurry with iso. Keep vacuum until you ready to fill your column. Your size of column i would think 30 minutes should work for dewaxing. Tip: put your iso in the freezer the night before you use it. You will save on dry ice.

First i would distill your solvent before you even do another run. I’m betting you have water in your solvent if your extracts are keep coming out that way. Make sure you’re using a molecular sieve correctly. Invest into a wax trap with that short of tubing/hose length. Your recovery pump will thank you. Hope this helps.

you want to really ram the material in there. I pack a few inches by hand then smash it down with a wooden rod until it’s nice and tight, then continue. This way I can fit way more in the tube.

For soaking, I do both ways. I’ll fill the column until no more butane can fit, then let it soak for around 10 mins. I used to soak for 30 mins but I was picking up too many waxes. Longer soak = more stuff pulls out, and not always good stuff you want. You can run it straight through without any problems if you want.

My process now does a partial soak, around 10 mins, then I slowly drain it into the collection pot. As it starts to drain, I open the injection valve again and let more butane flood through the column into the pot. I do this until I have no solvent left.

Your pump isn’t too big. For vac, it simply just removes the air and other gasses from the atmosphere. A bigger pump will do this faster than a small one, but once you reach full vac and there’s nothing left to remove, the pump just holds the vac at that point. You don’t have to worry about pulling too much vac with this.

What I do when purging is run the pump until I’ve reached the desired vac level, then close the valve and shut off the pump. Let the chamber hold the vac level for a few hours. When you come back you’ll notice the level decreased slightly as butane and some of the more volatile terpenes have evaporated off and are creating some atmosphere. From here you turn on the pump, open the valve, and pull vac to your desired level. You might have to go low and slow at first to prevent your extract from turning into a giant muffin and going everywhere… Use your discretion here with vac levels. The deeper the vac, the more likely it is to muffin. After a few hours in the vac this doesn’t happen anymore and you can generally go full vac levels.

I generally have my extract in full vac levels for about 2-3 days before it’s done. I’ll start at -20 to -25 for the first pull, and then after than as deep as my pump will take it. around -29.