Although Hydrodistillation (HD) is arguably the best choice from the conventional techniques, I would suggest looking into energy saving, greener alternatives such as microwave hydrodiffusion and gravity (MHG). MHG has been reported to yield results comparable to HD in less time and consuming less energy. See below:
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water and steam distilltion,cohobation, maceration and enfleurage are the most widely used method for extraction of essential oils.. But among these method Steam Distillation is the most favourable method used to extract essential oils from plants for use in natural products. This happens when the steam vaporizes the plant material’s volatile compounds, which eventually go through a condensation and collection process.
Hydrodistillation is a conventional method that can be applied both in the laboratory and large scale for the extraction of essential oils. This techniques apply to oils that are less dense than water (specific glassware is otherwise required).
Depending upon the type of crop there are various methods that fit differently for peculiar crops. Mainly, there are three methods which are Steam Distillation, Hydro-Steam Distillation and Hydro Distillation. I think the most preferred is Steam Distillation as it is the most economical however due to less volatility of components in some crops we need to perform more than just one distillation techniques. They may first require steam distillation and then Hydro-Steam distillation, for example. Hope this helps.
Steam Distillation is the most popular method used to extract and isolate essential oils from plants for use in natural products. This happens when the steam vaporizes the plant material's volatile compounds, which eventually go through a condensation and collection process.