Originally Posted by Carraxe
Terpenes are very volatile. Alcohol dissolves both trichomes and the cannabis oil that is inside, and allows the terpenes to evaporate quickly. Cannabinoids are not volatile, so I guess what you get after purging the oil will be a mix of cannabinoids and non-volatile impurities like water, waxes, oils and proteins.
I believe that the video by Jeff Ditchfield above in post #1 states that the turpenes are preserved in the method he uses ?