Post by Rik Wallin on Apr 6, 2007 12:28:03 GMT -6
Essential Oil Extraction
There are various methods for such extractions. The most common method is used for relatively volitile, water insoluable compounds. This is steam distillation. This technique requires a standard (simple) distillation apparatus, a speratory funnel, and a few flasks. The herbs are pulverised in some manner, Placed in the still pot with a relatively large amount of water, and the water is distilled off. The distillate will also contain the essential oil as a film on the surface of the water and on the glassware. Water is continually added to the still pot as distillate is evolved so that the mixture does not go dry. You have extracted essentially all of the oils when the distillate is no longer cloudy. Once the distillation is complete, you must remove the desired product from the water and glassware with a solvent. The solvent must be water insoluable, and for the purposes of this group, must also be relatively nontoxic and easilly removed. The best choice would be super critical CO2, but the equipment needed to use this solvent is not easily obtained, and the procedure is far more complex than the norm. Practically speaking, I would suggest either diethyl ether or pentane. Both have a very low boiling point which makes removal fairly easy, and niether is very toxic. The glassware is rinsed and the distillate is extracted several times with the solvent which is then evaporated to yield the oil.
Pulverization of the herb can be accomplished in several ways. For dried material, a coffee grinder, blender or mortar and pestle can be employed, the choice depending on the nature of the herb. For fresh, leafy material, several freeze/thaw cycles followed by blending with water works quite well.
One main difficulty that is encountered is bumping or boiling over of the still. This can be reduced by never filling the still pot more than half full and using a boil easer. Also, a claisen head between the pot and the condensor may help.
ODCO Inc. Jim
There are various methods for such extractions. The most common method is used for relatively volitile, water insoluable compounds. This is steam distillation. This technique requires a standard (simple) distillation apparatus, a speratory funnel, and a few flasks. The herbs are pulverised in some manner, Placed in the still pot with a relatively large amount of water, and the water is distilled off. The distillate will also contain the essential oil as a film on the surface of the water and on the glassware. Water is continually added to the still pot as distillate is evolved so that the mixture does not go dry. You have extracted essentially all of the oils when the distillate is no longer cloudy. Once the distillation is complete, you must remove the desired product from the water and glassware with a solvent. The solvent must be water insoluable, and for the purposes of this group, must also be relatively nontoxic and easilly removed. The best choice would be super critical CO2, but the equipment needed to use this solvent is not easily obtained, and the procedure is far more complex than the norm. Practically speaking, I would suggest either diethyl ether or pentane. Both have a very low boiling point which makes removal fairly easy, and niether is very toxic. The glassware is rinsed and the distillate is extracted several times with the solvent which is then evaporated to yield the oil.
Pulverization of the herb can be accomplished in several ways. For dried material, a coffee grinder, blender or mortar and pestle can be employed, the choice depending on the nature of the herb. For fresh, leafy material, several freeze/thaw cycles followed by blending with water works quite well.
One main difficulty that is encountered is bumping or boiling over of the still. This can be reduced by never filling the still pot more than half full and using a boil easer. Also, a claisen head between the pot and the condensor may help.
ODCO Inc. Jim