I don't have a link to a tek, as I've combined my findings to make the best quality oil with my current understanding and available technology. It's evolved over the batches and is pretty good I think now. Though you could find something similar on the internet. It does use food grade grain alcohol, close to ethanol.
I start by grinding the flower to small pieces, or use shake which is significantly less expensive and of similar quality, and matters less if your not gonna smoke it.
Next I take 3-3.5 ounces and cook it in the oven. I've tried a few different things. Mason jar or a Pyrex pan. I've done some smaller batches in the past, but now I do 4 ounces at once, a normal size mason jar doesn't usually fit everything. Ive used pickle jars and jalapeno jars which are larger and can fit everything. I heat the oven to 245, and put it in there for an hour, rotating and shaking it every 15 to 20 minutes. Don't cover the jar too tight, as it can explode from pressure. If you use a mason jar, you can use foil with the lid instead of the normal metal cap. I also use a temperature gun on my oven to check on it, many ovens will not be accurate.
I only cook 3 ounces because I keep the rest uncooked to use later. Heating the CBDa will turn it into CBD. You probably won't get everything converted, so there will be a little bit left. You'll keep some of the terpenes if you cover what your heating. Some people believe that the terpenes in cannabis, which give it flavor and taste, can be helpful. Personally, I believe that some of them may be helpful, but some of them are harmful, especially when inhaled. Helpful in the way that they could boost the effects or create strain specific effects.
Now to the uncooked 0.5-1 ounce, I keep that so I can have CBDa and a little THCa. It's commonly thought that you need to heat these acidic cannabinoids to make them useful, but this is not the case. The acidic version like CBDa and THCa have their own effects, such as a much more powerful anti inflammatory effect, stronger anxiolytic effects, and different serotonin effects. I would also like to add that normal CBD is excellent for blood pressure. If your goal is to get high, then youll probably want to turn your THCa into THC. Leaving some uncooked will also make the final product taste very strongly of the original strain, if your into that. There's another cannabinoid called CBGa, which is the precursor to CBD and THC, when the plant is growing it goes from the enzymes it produces, to CBGa, to THCa (or CBDa), the THCa will then degrade into THC, then finally into CBN. You could make your own CBN by heating THC for a long period of time. Another cool thing you could do is convert CBD into D8-THC with citric acid. I'll also note that CBG/a is supposedly good for your gut health, inflammation, and protects your brain. Ive taken higher doses of CBG, and experienced some irritability when taking it, but I can't confirm that it was from that, I'll have to experiment more in the future.
Now onto the next step.
Next I take all of the material in the jar, cooked and uncooked, and cover it with 95% food grain alcohol. I use this because it's safe to consume. I assume I can't get 100% of the solvent out later, and using isopropyl or butane would not be safe to consume. So I cover it, shake it up, and stick it in the freezer. Shaking it every so often. You could leave it in for a few hours or days, you might get a little more out. If you leave it for more than a few minutes, you'll get a lot of chlorophyll, which will make the final product very dark due to how light interacts with it. I put it in the freezer to try and reduce this a little bit, but it probably doesn't help too much, nor does it really bother me.
After letting it soak in the solvent, I take it out and strain it into a bowl using a nut milk bag, then transfer it to a beaker. Now here is where my process can definitely be improved. Currently, I put the beaker in a pot with a small amount of water, to evaporate off the alcohol. This is kind of wasteful, as you lose the alcohol after now. Instead, and in the future, I would like to set up a distillation apparatus so that I can catch all the evaporating alcohol to use again. I just haven't got the equipment yet.
Now you should let all the alcohol be removed from the solution. I keep it at about 120-150 degrees fahrenheit. When it's done, you'll have a small amount of black oil, 15 to 20 grams of pure concentrate. I assume the efficiency is about 85-90% from what we started with. But this isn't all, the oil that is now in the beaker is very thick, it's hard to get it out in its current form. So, take the amount of concentrate you have now, and subtract it from the final amount you want to have. I turn 4 ounces into a 60 ml bottle. Usually I have about 20 grams of concentrate. So Ill use 40 grams here. I have another measuring cup, I fill this with a mixture of MCT oil, grape seed oil, and sunflower lecithin. MCT oil vs grape seed oil is a choice you can make, some people's bodies don't react to MCT oil well (nausea, usually from large doses, 1+ tbsp at once, especially if you've never had it before). I use a combination of all three. The MCT may help with absorption into your body later as well as bind together in the final product better. The sunflower lecithin is an emulsifier, which will help your body absorb it when you take it. Use at least 1/3 sunflower lecithin. These 2 oils also can have positive effects on your health.
Now you take this mixture, and heat it up until it's homogeneous. Then dump that into the existing black oil concentrate while still heating it to dilute it to your desired dosage and overall amount. Carefully shake the beaker in a circlular motion to help mix it in. I estimate that with 4 ounces, you'll get about 250-350mg of cannabinoids per gram in the oil. That range depends on your starting material potency and amount.
Something else to mention is that eating cannabinoids provides a different effect than smoking them. Your body digests and metabolizes them differently. When it comes to THC, which there will be a small but notable amount of, especially if you have no tolerance, your body will turn it into 11-hydroxy-THC. Depending on your genetics and how well you absorb it (some people can't absorb edibles at all), it will be about 5x stronger than the same amount smoked, while lasting longer. If you don't want any THC, make sure what your getting has none or very little in it. Personally, I don't like taking pure THC strains anymore, but the tiny bit that does occur in CBD dominant hemp, does boost the overall effects in good way unless I take too much.
To respond to a few other things you said. Inhaling can have a different head space effect, yes. With that said, eating it does produce a more powerful, sometimes more sedative effect, more psychedelic. The first time I made THC edibles and took them, it felt like the first time I smoked, everything was hilarious and I talked a lot. I also stopped smoking due to my lungs, unfortunately from covid, but I've found now that taking oil is a lot easier to do consistently (primarily CBD), and is much less addictive than smoking (because the act of smoking itself can be addictive), so it feels like less of a "drug".
My other comment about pharma may have come off a little harsh. I do believe there is good, but also bad. Some doctors are more empathetic and understanding, while others are there for their job, don't research outside what they already know, and push what they are told to. To be the best, you must have a genuine interest and desire to know more, maybe even an obsession, with whatever it is. Pharmaceuticals certainly have their place, as not everything can be solved with nature. Though I also believe many drugs produced by pharma are designed to be sold and make money, not to cure and help people, which is a conflict of interest.