First ethanol extractions - please critique my process

Hash and Stuff Extraction
, , , ,
1

Hello all, Im currently looking into doing my first ethanol extractions, with the ultimate goal being cart production.

Looking for all and any advice that could help. I have run my original draft through chatgpt to try and take out all of the inane ambling so excuse any oddities.

Ive been researching the last 3-4 months and grabbing deals on used kit when possible. Just a few last things I need and then Im ready to go….But I still have a few questions that need sorting before I crack on. I also need to try and combine all the figures Ive found for various temps, pressures, timelines etc and try and find a good compromise.

I want to have a clear and simple process written in front of me to ensure I don’t make any stupid mistakes or have to waste time and let ethanol warm up etc.

This is very small volume, nowhere near commercial. I have no cold room or anything like that. Maybe 1kg once I have the process down but not against doing multiple runs.

Current kit available:

Ultra low chest freezer (-86c)

Buchi r300 rotary evaporator with f-105 recirculating chiller (-10), v-300 pump

2x 150ml buchner filters with 2000ml flasks

12l Vacuum purging chamber

To try and put it simply my current rough process is as follows:

1. Biomass Prep and freezing

  • Break up large buds/trim (not powdered).

  • Optional: Freeze biomass (worth it or not?)

  • Store ethanol in ultra-low freezer

  • Questions:

    • What temps would you use? Go full -86 or find a middle ground about -60?

    • What containers to freeze ethanol? Assume my cheap ebay masons wont cut it?

2. First Wash

  • Combine frozen ethanol + biomass.

  • Agitate however many times over wash period

  • Strain with colander or mesh.

  • Collect ethanol solution.

  • Questions:

    • Ive got so much conflicting data on wash times/temps. Are there any useful charts floating about? Any preferred data points you guys use would be extremely helpful.

3. Second Wash (Optional)

  • Remove additional clean ethanol from freezer

  • Perform additional wash if desired.

  • Strain again

4. Filtration

  • Stage 1: Buchner filter (Whatman #4, ~20–25 µm).

  • Freeze solution again (time TBD).

  • Stage 2: Buchner filter (finer paper, e.g., Whatman #1 at 11 µm or lower).

  • Questions:

    • Do I need a lower micron filter for final pass?

    • How long would you return to freezer for between passes?

    • Only using a cheap 3cfm single stage pump that came with my purging chamber. Plan is to just replace the oil often. Could I use the Buchi pump for vacuum filtering or not worth it?

5. Solvent Recovery

  • Options:

    • Source Turbo (simpler, smaller batches).

    • Rotovap (Büchi) with pump + chiller to -10.

  • Questions

    • Was probably going to try and use source turbo for first few small batches while learning

    • Any preferred setting for the rotovap as a starting point to work from? Temps/pressure/rotation

    • Is my chiller at -10 man enough for the job? Need more reading on the 20:20:20 rule

6. Crude Handling

  • Collect extract with minimal solvent left.

  • Questions

    • What and how can I store this before purging? And how long? Containers?

7. Purging

  • Current setup: 12 L vacuum chamber + pump.

  • Spread thin on silicone mat

  • Control temp with hot plate/mat.

  • Start low temp, ramp slowly (avoid overheating).

  • Flip after 24 hours

  • Keep purging until bubbles stop? 48 hours?

  • Questions:

    • Again temps/times would be useful please

8. Decarb

  • Heat under controlled temp on stirring plate with mag stirrer, or best to use jartech? (do you screw top on or not?)

  • Completion indicator: bubbles stop.

  • Questions:

    • How much can decarb at once?

    • Any better options than a heat mat for heating the vacuum chamber?

Eventually I will have a proper vacuum oven but ive splurged too much for now.

9. Formulation

  • Warm concentrate

  • Add terpenes (3–6%).

  • Mix thoroughly.

  • Questions:

    • How long can I store after this?

    • How should I store for maximum duration?

    • What containers are best?

10. Cart Filling

  • Options:

    • Manual syringes.

    • FiftyShot/Sharrb cart filler or alternative?

    • Cart Farmer 250(?) (better reputation, expensive shipping/tax and duties). Not sure if this would be overkill for my batch size.

  • Cartridge choice: Looking at ccells, TH2 or Ceramic EvoMax (need feedback on what works best with this type of concentrate).

11. Storage

  • How to store finished product both before and after in carts?

  • Best containers?

  • Refrigerate or freeze?

Yield Expectations

I know its impossible to predict but does anyone have a rough range of yield % I should be aiming for with this process? At least I know if I’m way off then I can look back at the process to see if I’ve gone wrong somewhere.

Finally:

· Is there anything fundamentally wrong with the way I’m planning to do things?

· Anything from experience you would change?

· Any tools I’m overlooking that would be useful?

· Biggest points of error and things to look for?

Thanks in advance

2

Your ethanol probably won’t stay cold enough to avoid pulling undesirables while still getting a respectable yield, I would recommend looking into filter medias to clean up your extract prior to decarbing. Also use a salad spinner to get more ethanol out of your biomass to boost yields on your wash step.

4 Likes
3

I love your name Mr. Danklestein

4

Ah thats frustrating.

Do you mean in the wash stage or in the filter stage?

Im sure I can get the solvent mixed and back in the freezer in 15 or 20 seconds or so?

If during filtering, I suppose I could try and jacket or insulate my flasks. Not seen anyone mention keeping it chilled at this stage. I was trying to avoid anything to do with dry ice.

Again I’ve not read anything about filtering extract after solvent recovery. More research to do.

I was considering the AC and diatomaceous or whatever its called in the buchner stage but was hoping the low temps would make it unnecessary.

I think I’ll do some tests with the ethanol, freezing it down to -86 and seeing how quickly it warms.

Any recommendations on kit for measuring at those temperatures?

5

No need to filter cold. Once your solvent has left the material as a solution, there is no chance of pulling undesired compounds from the material. Filtering cold does make the removal of suspended solids a bit easier, but nothing a proper filter cant handle warm.

1 Like
6

Needs a panda and your purge is mostly irrelevant given you’re planning to decarb everything

EtOH carts are still viable in some locales. Plenty of exploration of all the bits you need lying around here.

1 Like
7

Makes perfect sense thanks

@cyclopath I did look for panda spinners but they arent available here. Plenty of the no name chinese copies though. I was considering one but unsure how worth it if just doing kg at a time or something.

Anyone know if the mods the one member makes for them fits the chinese copies?

When you say “mostly irrelevant” for the purge, do you mean dont bother doing it or just give a quick preliminary blast and let the decarb take care of the rest?

Not really worried about market viability. Ive had enough of smoking and dont trust any of the blackmarket crap around here or online. Plenty of friends thinking the same.

1 Like
8

Ethanol isn’t all that easy to remove, so telling you can just go straight to decarb without actually doing it myself and getting or doing the residual solvent analysis would be irresponsible.

I have done that work for decarbing BHO, and in that use case I would characterize a pre-decarb purge as “completely irrelevant”.

“Mostly irrelevant” ?!?

Depends on how you actually implement your decarb and what you’re playing with for rules.

Eg: if you Decarb under pressure to retain terps? (or “jartek” in a well sealed jar), then you will also retain any residual ethanol.

Are you able to submit samples for 3rd party testing? Because a data informed purge is always better than just guessing.

1 Like
9

Thanks, again that all makes good sense.

First small batch I will probably just try a standard hot plate decarb, and then do another jartek style just to see how things compare and try and get some semblance of my own data.

I’ve spent a lot of time last few days reading as much as I can in the decarbing under pressure threads.

I still have more to read but from what I can gather it’s more about the inert atmosphere backfilled in rather than the pressure itself that seems to be preserving terps?

All of your designed and built kit is so impressive, but probably overkill/spend for my planned operation.

I believe any sort of 3rd party testing would be difficult/problematic where I am, however, I would not be against buying some rudimentary testing hardware myself if it’s not extortionately priced. Buying used lab kit seems to be my new hobby

I do love the idea of some “dank” smelling and tasting carts for home, but I’m also quite big on the stealth aspect.

I don’t have any fabrication experience but I’m pretty decent at cobbling bits together to make things. If there was something I could put together easily with off the shelf parts I would definitely be keen to give it a go.

The depth of the subject seems to get exponentially deeper the more I read so the plan currently is to start simple small batches and try and evolve so I can learn as I go.

1 Like
10

Does a 30 min wash at -65 sound like a decent starting point?

Also I was hoping to get away without using any media like celite while filtering, just whatman paper.

Is this totally unrealistic or does the temperature make it possible? Can drop to -85 if that improves things.

I think cart filling tools are the last thing I’m waiting on now.

11

Too long & too cold imo. It will work, but is not necessary

See Eg: It washes the cannabis and then it washes the cannabis some more

IMG_5633
IMG_56331144×1230 60.7 KB

This lil critter was getting 95+% of available cannabinoids in a 90seconds wash. At -5C we were able to achieve EHO that was viable in vape pens in the local market.

Spun is more fun

2 Likes
12

Is that down to the kit used or would still be viable for my methods?

My line of thinking, please correct me if I’m wrong, was to go beyond -20 to avoid pulling as many fats/lipids as possible to try and make the filtering process much easier.

I spent an hour or so reading that thread last night but there’s so much extra noise that goes over my head it was hard enough to draw any solid info that lines up with my proposed process. Ill try again before smoking and see if I fare any better ha.

I’ll be ordering one of the cheap panda spinner copies to get the remaining ethanol from biomass, just need to work out what sort of bag to use inside.

Do you guys use the centrifuges for more than just the removal?

I understand my plan my not be the most efficient or cost effective, but I’m just looking to make the most of the kit I have for now, and will look at improvements or upscaling kit much later on.

This is just me messing about at home not a commercial venture. Might be looking to run the process 4 or 5 times a year max so I’m not too worried about some inefficiency unless it spikes cost.

13

Well I’ve done my first washes this afternoon.

Not ideal having only 11 and 8 micron filters but it seems to have gone ok.

Second wash seems clearer than the first which I wasn’t expecting.

Not sure whether to pop it back in the freezer and wait for my smaller um filters tomorrow or just wack a bit in the source turbo now and see how it comes out.

Tomorrow will be setting up the rotovap and trying to get my head around that bad boy.

14

1st wash gets most of the stuff that you’re gotta get. Can you explain why?

Pretend all washes have equal efficiency (they don’t, one might expect MORE efficient, because solvent to solute is higher later)

Imagine that the 1st wash gets 75%

2nd wash gets 75% of the 25% you left behind the first time (18.75% of your starting…). You’ve now got 93.75%!!

3 wash gets 75% of the bit you left behind the second time. Let’s call that 6.25% of initial target. So you net only 4.7% of your target on that third wash. You now have better than 98% of your target.

1 Like
15

Bump!

1 Like
16

Don’t stress the roto too much, really the only thing that you lose is time if things don’t go properly. Just make sure your chiller is on! You don’t want ethanol getting into your vac pump.

3 Likes
17

Yeah obviously that makes sense thanks.

Just threw me a little as it was at odds with all the random YouTube vids I’ve mashed into my brain the last few months.

Guessing the -65 temp has paid dividends.

Not going to be able to do much more tonight so I’ve thrown them both back in the freezer while I recover a small batch then tomorrow morning will start on a vacuum purge.

20250925_185002 (1)
20250925_185002 (1)1920×1081 211 KB

If 2nd wash is that clean is there any downside to combining them? I saw recommendations not to, but that was with a greener 2nd.

I’m sure it’s probably not worth it at my scale but I’ll be doing some bedtime reading on thc testers like the tcheck3 / purpl pro. Even if it doesn’t make total economic sense I like to know I’ve done the most/best I can do.

18

TLC plates are worth looking at

3 Likes
19

Thanks will check it out

20

Presumably a warmer second wash…

Recommend both the thread linked under “bump!” above, and Optimizing your RotoVap

Along with Thin Layer Chromotography

1 Like