Oven tek SOP criticisms welcome

Hash and Stuff Extraction
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I guess my last post has too many questions, so I will try it another way. I found this basic SOP on Reddit

I was wondering what criticisms people have of the technique? Anything missing here? And does anything really changes for ethanol extracts?

Reposted Steps from CaliNuggLove - edited by the Future4200 community.

NOTE: Oven tempertures over 100 f may achieve a sugared or buttered up consistency throughout part, if not all of the slab. For a clear shatter, try to avoid the nucleation/buttering once the oil is in the oven & under vacuum.

1) Preheat vacuum oven under vac to 91 f.
This is a good starting point. Generally have to take it up to 95-97 just to break the viscosity of the slab, depending on strain. Some batches/strains took over 100 f to break the viscosity, generally stay under 100 f.

2) Once the oil/slab is up to temp & viscous enough to start the vacuum process, vac. down to -20 hg slowly without forming a muffin in the oven.
Depending on the strain & viscosity, vacuum down the oven chamber so that the slab is visibly off-gassing, as well as flattening/spreading out. Avoid releasing the vac, vacuuming down, releasing vac, etc. can be detrimental & cause un-necessary agitation of the oil. This also introduces atmosphere into the oven & slabs more times than needed, & will ultimately fight against the oven’s heating mechanism.

3) Reach a full 29.92 hg in the oven chamber.

4) Re-adjust the temperature to anywhere between the starting point of 91f - 93f.
Even if the slab seems to have a high viscosity at this point, set the temperature lower as a base starting range. Keep the oven temperature set on the lower range for 24 complete hours. During that 24 hour time frame, do NOT touch, un-vacuum, or flip the slabs. Just leave them for a 24 full hours at the initial temp & full vac.

5) Flip.
After the initial 24 hour period, open the vacuum oven chamber, clean up the edges of the slab by folding, & flip the slab completely over onto a fresh piece of parchment/PTFE sheeting. Place the slab back in the oven & gently vac at baseline temperature. Slowing ramp up temperature depending on strain. We want to see off-gassing.

Opinon 1) Flip slabs every 24 hours, sometimes more, sometimes not as much. It really depends on each specific batch. Do try to flip a minimum of at least 4 times throughout the entire purge process of 4-5 days [72-96 hrs.].

Opinion 2) If you still have a few bubbles left in the slab after purging for a few days, they are more than likely either trapped atmosphere from flipping the slab (probably not), or terpenes boiling off (which you don’t want). A lot of times, just pulling the slab & letting it sit at atmospheric pressure will let the oil “rest” & those bubbles with almost disappear over the “cure time”. If not, Use a heat gun set to low & held about 12-16" away from the slab. It makes the slab look BEE-UTIFUL when done. Just be careful to not use a super hot heat gun, & to not burn the terps off, or evaporate half of your slab with it. Easy & slow wins this race :slight_smile:

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I just got an oven but I don’t really know how to use it. My goal is to get some clean terpy absolute shatter, with quality starting material of course. I have read a lot about it, but I am mainly just looking for some good suggestions and help.

Some things for clarification

  1. My understanding is that a thin film allows for easier evaporation of solvent. How thin?

  2. 95F preheated oven is my understanding for shatter. Is that correct? What about vacuum? How deep do I need to go to get clean shatter and keep as much terps as possible?

  3. Flip and/or Whip? Useful? If so, how often?

  4. How do I know I have clean shatter? Obviously, no more bubbles, but is there any other signs?

  5. I typically purge the bulk of the solvent with a roto. I assume nothing about 95F here too, and lower pressure. What is a good point to cut from the roto to the oven? I would assume just enough to easily get it out of the flask.

  6. I’ve read things about bumping the vacuum when alcohol bubbles get big. I do not understand what that is. Can anyone clarify?

  7. Do I turn turn off the pump during the purge? If so, when and for how long? How often should I reopen the value and pull vacuum again?

  8. Typically how long should I expect to purge a sheet of shatter? I understand things are based on a lot of factors.

  9. I’ve read it was important to depressurize the oven slowly. Is that true? How slow?

I’ve really been trying to put together a basic SOP and I have run into all these questions during my research.

Thanks in advance for all your help

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I went ahead and merged the two topics because I think you have all valid questions.
We have been looking for a way to ‘wikify’ this information into static, solid documentation.

Lets use this as a test for the Wiki system - any member can now edit the OP with “Reposted Steps from CaliNuggLove” - Community input is encouraged, and feedback on this kind of system is encouraged. If this doesn’t work we’ll have to move to a real deal wiki.

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A lot of answers to your questions come down to experience and product in. Here’s what I got.

  1. You will find a sweet spot of heat, vac, and solvent ratio.
  2. Material dependent.
  3. Spread thin, avoid a flip. One flip max IMO
  4. Certified lab test
  5. Probably referring to venting a bit to lay the bubble back down onto the warm shelf. Try to avoid big bubbles and ‘muffins’ in the first place by pulling a vac slowly. The oil is getting heat from the shelf, which gets it’s heat from the sides of the oven. Vacuum is a tricky bitch, there is no ‘air’ to help circulate the heat around. That’s why you don’t see anyone putting a fan in their vac oven. Keep as much oil on the shelf at all times.
  6. If you apply too much vacuum you risk off gassing THC. If you have a gentle pump leave it on.
  7. Material dependent.
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Forgot to add this First…Calibrate your oven a few times before use. Cant stress this enough!

WOW…it looks like that SOP is like practically how i operate my oven with some little differences. I pre-heat my oven to only 85F and leave it that way until the oven is full…or im done for the day.

I then raise my temps to 88-90 for an hour or 2. By this time…all my oil that was once 85F is now 100% around 90F. I then pull vacuum at full speed though. I pull all the way down till my needle is pinned below -29.9hg as i live 2 miles from the beach. I use small i think 1.9cfm AI pumps to keep from eating up too much terps

I keep the pump running for the next 1-3 hours depending on the way the slab is looking…Once the varying size bubbles become more uniform and much smaller. I close my vacuum port and leave it for the night. The next morning ill let air back in. Raise the temp by 1F and let it all melt down for like 30 mins. Pull from the oven and flip. I then put all them back in the oven. Raise the temp again by 1F and give it an hour. Pull Vacuum again for 1-3 hours. I will close my port and repeat the process until my slabs are about 95-98% bubble-less. Finally i will let all the air in raise the temps final 1-2F before i remove for the final time in attempts to pop the bubbles.

This usually takes between 3-5 days of purging and i try to stay under 103F by the time i finish…most times i can keep it around 100F.

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What kind of oven / pump do you use. How are you doing your calibration?
Found it best to pull vac right away since that’s how the Cascade ovens controllers are designed to operate to avoid over-shoot. Kind of in a bind if you have to keep the oven on but no vac while you fill it up throughout the day.

What do you use to determine “all my oil that was once 85F is now 100% around 90F”?

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The reason i keep my oven at 85F throughout the day or till i fill it cause i dont want to cook the oil thats in the oven from previous runs in that day. Sometimes my single runs dont fill the oven. So i run until my ovens are filled or im done. I dont want to have a run of one strain…pull vac…then have to release it to put more oil in that oven. So i just keep my oven on with runs from the day. When im done running or the vac is full…then i wait till all the oil has gotten to the same temp(90F) as the oil i run at 9am might not be the same internal temp is the run i just finished at say 3-4pm.

I use all AI ovens .9 and 1.9cu ft ovens with the matching pumps as they sell on their site. I figured they spent more time on matching the pump to oven then i could ever. I only do the calibrations on the first time use. I do the calibrations according to the manual…i think this video explains it but i use the manual:

I open the oven fast and try to get laser temps all all trays and in different points. Ive done this several times over the first day with my ovens. I will adjust my oven accordingly.

I keep the oil in the oven without vac to get the extract to a higher temp than i recovered. This makes the surface retention of the extract a bit easier to pull the solvant out, and i know 100% the temps are stable by experience with the laser thermometer over time.

Im sure my tech aint the best by no means but its what works and pretty darn well. Id like to here others and maybe i can improve my tech. Hope that answers your questions. Thanks for having me clairfy those details. I guess im not good with the SOP things.

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Great info here, the only thing I would add is that you can go higher in temp, depending on what terpenes you wish to keep. Not all terps are created equal. There may be reasons to go higher, completing your purge faster, increasing your production, and likely %THC in your final product. It may be a business decision as much as a scientific one.

Also, what about different purges for different solvents? I might want to go higher with ethanol than butane. Look at the boiling points to make a decision.

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Great point. I ain’t scared of 115f on a super thin spread.

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For the record I sell Cascade, and don’t mean to start a flame war. I am super skeptical of that temperature calibration but it sounds like you figured out the art of it which is very important no matter what. I haven’t seen a temp probe in the Chinese oven itself. Honestly no idea how it knows what temperate it is other than radiant heat from the outside of the chamber (doesn’t make sense).

As for the laser thermometer, you have to vent the oven and open the door since IR cant pass glass. It’s possible to see a 10-15f air temp difference when venting which translates to +~5f on the shelf. All of course dependent on ambient temp vs oven temp. Something to keep in mind. this may be why one would want to vent slowly, as to not “over-shoot”.

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I agree, the calibration seems sketchy, but we don’t care about absolute temps, just what works for our products in our lab. Repeatability >> Accuracy. That being said, I would love to actually check the calibration on my cascade ovens, but havent found a great way to do it. Anybody squeeze a thermocouple in there while maintaining vacuum?

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yes i know you sell cascade. I know there is a possibility for heat loss when opening the oven door. Using a piece of copper on the tray your trying to capture the recording will help retain the temp long enough to capture a close enough temp i feel. Like i said…i wish i could get all scientific with everything. Im just doing this for personal head stash. I only smoke concentrates so i try to make them as good as i can possibly. Hopefully more people will chime in, and help me improve my tech. I just answered in this thread as i know this is pretty beginner stuff and the really smart people here have better questions to answer.

Sorry i dont own cascade ovens. Amazon has AI ovens on there site, which allowed me to take advantage of their financing so i was able to afford them. Otherwise…most ovens and this equipment is outta my reach as im in a non complaint state, with limited funds. You can read on Icmag where i actually got a leaky oven from AI but they picked it up and replaced it very fast. So, my experience with AI isnt all peaches and cream. This is just what i have. Wish i could afford more sometime! :frowning:

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Dont be too discouraged, if it holds enough vac (look into elevation above sea level adjustments) and a somewhat even temp, you are good to go. The final product is all that matters.

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Love it. World needs more people like you!

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I’m liking the copper idea for trying to measure the actual temp inside the oven. What about throwing a thermocouple with the meter and everything in there so you can see it? Might be worth sacrificing a cheap temp meter. Exploding batteries might be a problem.

Kind of along those lines, anyone add thermal mass inside the oven to keep a more steady temp? I know more shelves helps with this. What about a sheet of metal, or even glass or stone?

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I do up to 102° flip every 12 hours. I always do this from a pour and never put the scrape with it. Since the scrape has been heavily agitated uit tends to want to cause nucleation sites. So we take that to the side adhd agitate it more into our honeycomb. We this always acheive under 100ppm down to 2.6ppm. While keeping a stable flavorful shatter.

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Currently using AI ovens. 3.2cf have been my favorite overall.

I recommend staging your oven in increments of -5. (Ex: -5, -10, -15) pull vac slowly while doing this. I let it sit on each increment for at least 5min. For the final stages I will pull a slow vac from -25 till I reach -27inhg. I will let this stage sit for 10-15min before pulling the final stage. I let that stage for another 10-15min with vac valve wide open. I flip every 24hrs and keep doing this for 5-7 days. Have had great results and consistently sitting under 20ppm Butane. Hope this helps!

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I start my oven at 100°F. Pull vac in increments and watch for action on the slab. As it stays active I slow the pull. It usually takes 45 min to 75 minutes depending on slab thickness to keep the surface active until I reach full vac. Leave it for 3 hours and then I put it into my 2nd day oven at 95°. From there I flip 1 time a day for 2 days and hold vac. 4th day I pull it out and put it in 85° finish oven. I let it rest over night and it comes out low ppm every time with great TERP content.

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How do you calibrate your vacuum oven?

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Set the oven to 10 degrees over operating temperature (~120) and let it sit empty for 3-6 hours under vac

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