do dried herbs still have oil in them?

[svrn]

is there still vegetable oil in a completely dried herb? Like if it is so dry that pinching it turns it into dust.

[eveheart]

If you think in terms of volatility, which is the oils ability to evaporate into air at room temperature, I think you can answer your own question. The very reason we smell these plant compounds is that they evaporate into the air and waft to our olfactory organ. Drying temperature, storage environment, and age of the dried matter affect the amount of volatile oils left in the plant matter. In most cases, a carefully dried  and stored sample won't be devoid of oils. If you wanted to quantify the loss of volatile oils, you would extract the oils from both the fresh and dried sample  and compare the yield. You could be less scientific and smell the dried sample to see if any aroma wafts from it.

[svrn]

So a dry herb definitely has a lot less oil in it than a fresh one?

[eveheart]

So a dry herb definitely has a lot less oil in it than a fresh one?

You would have no basis to jump to that conclusion based on the "fresh vs dry" criterion alone. Some of the aromatic compounds off-gas more slowly than others. And, of course, conditions such as "fresh" and "dried" describe only one aspect of the plant matter itself, but they do not indicate how the plant matter was handled.

[ciervo-chaman]

So a dry herb definitely has a lot less oil in it than a fresh one?

At least, the dried will never have more than the fresh. If from same batch. Can have same or nearly same if dried carefully

[svrn]

What does drying carefully entail? If you wanted to dry an herb in such a way as there would be no oil left in it, how would you do that?

[eveheart]

What does drying carefully entail? If you wanted to dry an herb in such a way as there would be no oil left in it, how would you do that?

Just dry your plant matter in a variety of ways by varying the temperatures, exposure to air, etc., and send your results to a lab for analysis. That should lead you, sooner or later, to the process that works best for your needs. (P.S. Don't forget to have the lab run a batch of your fresh plant matter to quantify your baseline, if you want the results to be expressed in percent loss of aromatic oils.)

[svrn]

wouldnt that cost thousands of dollars?

[sabertooth]

Look to age old methods of curing tobacco or drying ganga..... slow drying at room temp with good ventilation and around 40% humidity should preserve the oils in whatever plant matter you may wish to keep for long term storage. After reaching optimal dryness you can vacuum seal to prevent oxidation, mold , staleness and over drying.

[eveheart]

wouldnt that cost thousands of dollars?

I don't know of an "eyeball" method to determine if all the volatile oils have evaporated from a sample of plant matter. I can't even imagine why that information would be useful, but I don't pry into other people's business.

Bottom line: You asked, "is there still vegetable oil in a completely dried herb?" Since you are talking about determining if minute quantities of several different plant essences have completely left the sample, you'd have to test a sample of the material. You can distill your dried plant matter and see if any oils float on top of the distillate, but that would be an approximate result that wouldn't be accurate to the "none" level.