Source -- Peppermint oil is distilled from the perennial herb Mentha Piperita - which grows in the temperate climate of the U.S.A - Europe and Asia.
The so-called Japanese peppermint is derived from the herb Mentha aruensis - grown extensively in Japan -Brazil and California.
The oil is less fragrant than the piperita variety and possesses a peculiar bitter taste - possibly because of its higher menthol content. It is extracted by steam distillation.
Another popular flavour is spearmint - derived from the herb Mentha uiridis - grown chiefly in Michigan, U.S.A . It would be a step in the right direction if this plant were more widely cultivated - as the flavour is interesting - pleasing and produces a cooling sensation on the palate.
Owing to their high volatility - peppermint oils should be stored in a uniformly cool room and the containers kept well sealed.