Preparation of Concrete
Concrete is prepared by extraction (benzene) with yield 2-4%. Product will be dark green in colour.
To improve yield, moss is immersed in water for 6 hours and dried before extraction
Preparation of absolute
Obtained via alcoholic extraction of concrete for 6 hrs. Yield is approximately 60% and the colour will be dark green.
The mixture was cooled down in iced water bath before vacuum filtration to remove all insoluble impurities. Mixture can be decolourized by adding activated charcoal powder followed by ashless powder before vacuum filtration. Ashless powder will aid in filtration. Repeat Filtration as many times as needed (if the black particle is still around, filtration has to be repeated)
The liquid product was distilled under vacuum with high bp, odorless solvent and codistilled to give better color and yield of product.
When you are handling benzene and the product, please be extra careful. Benzene is carcinogenic and it is relatively volatile. Please discard organic solvent properly. As you know, oakmoss is an allergen, at the concentration you are handling, you should handle it carefully. There is a article on the production of oakmoss absolute with reduced allergic side effects (International Journal of Cosmetic Science # 14, Issue 3, p 121).
Fenaroli's handbook of flavor ingredients
By George A. Burdock, Giovanni Fenaroli
Edition: 5, illustrated
Published by CRC Press, 2004
ISBN 0849330343, 9780849330346