Terpenes decay Study
SweetSue;2755333 said:I'm looking over the research materials used in the post mentioned earlier questioning the choice of using dry plant material over wet, and a couple interesting things pop out at me.
The Volatile Oil Composition of Fresh and Air-dried Buds of Cannabis sativa
* It's worth noting that the study was done in 1995 and they were apparently looking for ways to be able to detect the presence of cannabis through smell.
* There were four samples tested: 1) fresh, 2) air-dried a week, 3) air-dried a week and stored in a brown paper bag for one month and 4) air-dried a week and stored in a brown paper bag for three months.
* Volatile oil content started off at 29% fresh and dropped off to 20%, 16% and 13% respectively. It's understandable that the OP found this information disconcerting. A loss of 31% in a week certainly gives one pause. But there's more to the equation than simply the volume of oil one can extract.
* Aside from the drop off of volatile oil volume, the most striking difference was in terpene composition. Using fresh material you have 92% monoterpenes and 7% sesquiterpenes. As they dry you begin to have a drop off of the monoterpenes as the sesquiterpenes increase. Let's take a look at the levels as we progress.
1) Fresh 92.48/6.84
2) Air-dried one week: 85.54/12.64
3) Air-dried one week, stored in a bag one month: 67.60/29.53
4) Air-dried one week, stored in a bag three months: 62.02/35.63
* In the fresh mix the predominant monoterpenes were myrcene (67% of monoterpene composition) and limonene (16% of monoterpene composition). Let's track those.
myrcene: 67.11%, 58.72%, 38.74, 32.88
limonene: 16.38%, 17.20%, 17.66%, 16.26%
It appears that the chief advantage this process of using fresh plant material and olive oil offers is the retention of those monoterpenes, most importantly myrcene. It's time to take a closer look at what we know about myrcene and its synergistic effects. Limonene actually increased with drying and curing, peaking at the one month point and then dropping off again to a lessor value than the fresh allowed.
* There were no terpenes entirely lost in the drying process.
* A steam distillation process was used to extract the oil. I'm not learned enough yet to determine the significance of this point, but I'd bet it's an important consideration.
The table included in the research paper linked to has an extensive list of other terpenes and their changes in levels throughout the experiment that are worth looking over. It's fairly obvious we need to improve our understanding of terpenes. We still have so much to learn.
