[Luc_H]

Hi AnaI,

I am not familiar with essential oils used to flavour oil but I can understand how this can be done.

Essential oils are made by soaking plant material (like rosemary) in a solvent then distilling the solvent or by using steam to extract the essential oil. The same essential oil can be used for both applications actually. Food grade essential oils are made using food grade materials (i.e food grade solvents). On a commercial/industrial level, essential oils are very concentrated making it almost impossible for any practical home use. There may be a big difference in concentration between cosmetic and flavouring.
Essential oils can be adulterated using a blend of other plant extracts or even fortified with aromatic synthetic chemicals. The whole industry is not well regulated and many products are fakes or adulterated. Often also, the prices are overly inflated. It is hard to find unquestionable quality material on the retail market.

I think that was one paragraph.

Luc H