I am unsure which is the correct terminology, infusion or extraction? For all practical purposes I will continue using infusion here. (What is the difference between the two?)

When making the infusion1 I'm using a ratio of 2 oz of dried, but not decarboxylated plant matter to 1 quart of grape seed oil. Any brand will work. The plant matter mainly consists of the buds and colas. These have gone through the curing phase already and are dry.

I put the plant material in the oil inside of a small 1.5 qt crockpot. The last time I did this, I let the crockpot sit on high for 8 hours before switching to low for 3 days (72 hours).
A lot of tutorials and online videos will say leave it sit for 4, 8, 24, or all the way up to 72 hours and more.
How long will it actually take until most cannabinoids are infused into the oil, without infusing other, unwanted compounds like chlorophyll?

I'm assuming that there is a breaking point where the plant matter is done decarboxylating, and the oil has extracted all of the cannabinoids.

I've done this kind infusion using coconut oil and I didn't get the same potency as when I did the infusion with grape seed oil. What is the reason on a molecular level that allows grape seed oil to infuse cannabinoids more easily?

1 Legality is not an issue since I live in a state where I am allowed to grow up to 6 plants of varying maturity and also produce my own grape seed oil infusions.

  • $\begingroup$ J. Robinson - I think I can answer your question but you need to dissociate the decarboxylation from the extraction (you say infusion). Otherwise, your extraction selectivity is different for the carboxylic acid opposed to the decarboxylated material, which makes your extraction oil and time a moot point. Time, temperature and solvent play a factor. Do you want to extract, then decarboxylate or decarboxylate then extract? The extraction selectivity will guide you $\endgroup$ – Beerhunter Aug 5 '17 at 20:37
  • $\begingroup$ I'm hoping that through the process of extraction the cannabis plant material decarboxylates itself and then infuse itself into the oil? I'm not a chemistry expert by any means, so sorry for the layman's terms. Is it an extraction and not an infusion then? $\endgroup$ – J. Robinson Aug 6 '17 at 3:09
  • $\begingroup$ Infusion could be used as an every day term. The chemical term would be extraction. To help answer your main question, I'm assuming it's a CBD or THC (or CBDA /THCA, or both?) compound that's being extracted? $\endgroup$ – Beerhunter Aug 6 '17 at 8:12
  • $\begingroup$ cross-post: cooking.stackexchange.com/q/83527 $\endgroup$ – Martin - マーチン Aug 8 '17 at 13:40
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    $\begingroup$ The question in its current state is considered by some as too broad to be treated scientifically and is likely to be closed. The reason for this is that there are simply too many unknown variables. For you personally the brand of grapeseed oil might not matter, but it is already a mixture, which makes the starting conditions quite unpredictable. Then obviously high and low are no temperatures. And we would need more information on which cannabinoids are being extracted, all that and more plays into extraction time/efficiency. $\endgroup$ – Martin - マーチン Aug 8 '17 at 13:57

The time taken (before there are diminishing returns) of extracting the herb is totally dependent on the solvent used, or in your case, the oil. If you were to use water, the answer might be days. If you used heptane, a couple of hours.

The decarboxylation and the extraction - a catch all chemical term for removal of components or a component from a particular solid liquid or gas phase, as opposed to infusion which seems to be specific to botanical extractions (so both are correct in this instance) - should be decoupled. If you start with the cannabinoidal acid and heat in solvent, you'll start extracting components at different rates, while also decarboxylating and extracting the cannabinoid. This reduces the selectivity of the extraction.

Again, depending on your chosen oil, the rate at which your desired components and undesired ones are pulled into your oil will differ. You seem to have a handle on which of your two oils is better. I would try two experiments:

  1. Heat the dry herb to decarboxylate; less than two hours should be ample and may even be too much. Then extract/infuse your oil. Bear in mind, the more oil you use also leaves you open to extracting more rubbish you don't want, as does extending the time. You're better cutting your time down first and monitoring potency (as extracting more undesired components will lower your potency in the final extract, so potency should increase as you bring your time down) and then experimenting on reducing the oil content until your potency decreases. A decarboxylation should take about one hour at around 110C, but it depends on the amount of herb you have and if it's whole leaf, shredded, milled etc. I'm talking fine material at kilo scale. Extraction under ideal conditions is done in six hours, depending on solvent.

  2. The second option is to extract at cooler temperatures (cool temp to 50-60C absolute maximum) first to get the cannabinoidal acids. If you have the facility, add base (diluted sodium hydroxide is ideal and would take minutes . Sodium carbonate dissolved in water may work but would be slow (days?) and you'd have to monitor carbon dioxide evolution). The acids you want will form salts and extract into the water. The neutral stuff you don't want (terpenes, waxes - long chain alkanes) stay in the oil. Separate the oil and water. You have a choice here.

    1. Add acid to your water layer - this may cause your cannabinoid acid to precipitate, so filter it off.
    2. Otherwise add fresh oil to the water, then acid and your cannabinoid acid will now be in the oil after mixing.

Whatever you choose, heat your cannabinoid acid to over 100 degrees Celsius and you should be done in an hour or two. Over 120 degrees Celsius may be too much. As I mention, some experimenting will be needed but try to ensure your herbs are consistent and not mixtures of different varieties each time.

As for your oils. One is more like a liquid "fat" - the coconut oil. The grapeseed oil is still a mixture, but is primarily "polyunsaturated" ( it's actually di-unsaturated) and about 50% bigger than the main coconut oil component. These oil mixtures are not usually used in chemical extractions as they're not pure. I assume you use digestible, non-toxic solvent oils. Otherwise I'd suggest limonene.

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    $\begingroup$ Please use paragraphs. This sort of wall of text is very tiring to read. $\endgroup$ – terdon Aug 8 '17 at 13:39
  • $\begingroup$ I am down-voting this simply because its terribly formatted. $\endgroup$ – Martin - マーチン Aug 8 '17 at 14:02

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