Western Juniper Oil Distillation and Marketing Project
Distillation - Raw material was steam-distilled at zero pressure in a 23 cu. ft., top-loading retort. A total of 13 batches were run through the system - nine were leaf and four were bole wood. Distillation residue was returned to the harvest site and scattered as mulch.
Leaf oil yield by weight averaged .206% for samples harvested and distilled in June, July, and August, and .405% for samples harvested and distilled in October and November (almost a 100% increase). Bole wood yield by weight for this project averaged .138% for the earlier period and .420% (one sample) for the later period (approximately 300% increase). Seasonal variation in oil content and improved processing techniques are two of a number of possible reasons for these differences.
Other key distillation phase observations include:
Tree laden with immature berries appeared to yield significantly less oil form leaf material than trees which had sparse berries.
A properly "tuned" steam/retort/condenser system should yield 80% oil recovery in three hours. Minimum oil yield from leaf material with such a system is expected to be 0.40%. A leaf oil yield of 0.50%-0.75% can be expected with more experience and properly prepared raw material. Oil yields of 1.0%-1.5% are projected in a 20-40 psi pressure system, based on previous work by Kurth and Ross (1954).
There are 300-350 gallons of run-off distillate waters for each gallon of oil produced.
Yield should increase if an efficient (minimal loss of oil) and cost-effective technique is found to dry material prior to distillation.
Essential Oils Analysis - Three samples of juniper leaf oil and one sample of leaf oil distillate water were analyzed using a gas chromatograph. (Interpretation of gas chromatograph readings have been questioned by Joe Karchesy, Oregon State University, based on previously published western juniper gas chromatograph results and his personal experience and research [Swan personal communication]). The crude leaf oil is colorless or pale greenish-yellowish with a characteristic basalmic odor. The leaf oil is somewhat unique in that its aroma is very similar to the aroma of the living tree.
For full report visit... http://juniper.oregonstate.edu/oils_abs.htm
