Lavender - what does 40/42 mean?

40/42 relates to the ratio of linalyl acetate and linalool. A natural lavender or lavandin can be made into a perfect 40/42 with the addition of some synthetic linalool or synthetic linalyl acetate. this is what perfumers and toiletries manufacturers want. But anyone who wants a completely natural lavender needs to buy lavandula angustifolia miller. With a natural lavender the proportions can vary from crop to crop. 

That is the way Lavender standards work in France. High altitude distillers can be told that what they are producing is not 'Lavender' because it doesnt meet the standard.

There are no right or wrongs here because the fact is 95% of essential oil if not more does not go to aromatherapy. There is though a true and false oil. For aromatherapy its easy enough as Maggie Tisserand says to source a Lavandula Angustifolia Miller.

You will find the 40/42 is probably a tough and prolific cloned variety called Lavendula Angustifolia 'Maillette'. True french Lavender Angustifolia Miller (also known as Lavender Officinalis is somewhat softer smelling or may almost lack a smell) This can also be obtained with a biochemists certificate of purity.

And of course (sorry my usual hobby horse) organic or AOC (appelation origine controlle) in the same way as you would buy a wine.

As an aside aromatherapists tend to reckon that what the true lavender lacks in strong fragrance it makes up for energetically. There is also the point that usually in aromatherapy there is enough of an emotional load without adding a strong fragrance which the client and their relations can take exception too.

But theres a good point - would you use a fine red wine to make a stew or the Supermarket's standard red wine? Why waste a fine wild harvested angustifolia if it is to be used in a cleaning product for which the 40/42 is ideal. And wouldnt you want the cleaning product to be fragrant? 

 Jeane Rose writes...

Lavender should have linalool and linalyl acetate in it in a proportion of 2:1 or about 40:20. It should never contain Camphor. If your Lavender has camphor in it, then you either have the wrong plants or the wrong earth. The essential oil is the expression of the earth in the plant. Camphor can be in Spanish Lavenders and spike Lavenders but fine Lavender will have a soft and soothing scent.
http://www.jeannerose.net/courses.html
Linalool is an alcohol like the alcohol in wine. The essential oil alcohols here are monoterpenols. They are bactericides, anti-infectious, antiviral, stimulating to the skin to heal, good general tonics and free of hazards.
Linalyl acetate is an ester. Esters are gentle in action, soothing to the skin, anti-inflammatory, effective on skin rashes and other skin problems. They can both calm and uplift and combined with the tonic virtues of alcohols are very balancing, especially to the nervous system.
This is why Lavenders are so desired by the skin care industry

Essentia