Flower in a vac chamber is slow because the the usual heating methods rely on conduction, when the flower that is contact with the heated surface area is dried out it acts as a insulator to the rest of the material, slowing down heat transfer. Adding a infrared heat element into the vac chamber is a good solution. Ive done it with some epoxy and a reptile light. Sped up the drying process significantly.
@Ruwan Very interesting post and paper! They go one to describe how to make “terpeneless” oil that is described and explained as more desirable. And how r134a is utilized to reduce levels of terpenes from essential oil extracts.
Essential oils are typically extracted or expressed from plant materials and are used for flavouring, fragrance and medicinal purposes. These oils typically contain quantities of undesirable compounds, particularly the terpenes, and the desired organoleptic compounds, which can be structurally related to the terpenes, but carry heteroatom functionality, e.g. oxygen containing functional groups such as hydroxyl, carbonyl or ether groups. One particular class of organoleptic compounds contained in essential oils is the terpenoids.
The terpenoid content of essential oils often contributes significantly to the desired organoleptic properties of the essential oil. For example, the aroma and flavour of citrus peel oils is largely determined by the presence of citral (an aldehyde), nerol and geraniol (alcohols) and their ethyl esters.
However, the terpenes are often present in large quantities in essential oils and tend to dilute or mask the desirable properties of the organoleptic compounds.
The use of hydrofluorocarbons such as R- 134a in the production of essential oils having a reduced terpene content is taught in EP-A-1332201.