I believe that to have organic plants for consumption, i.e. in the production of dried herbs and fresh fruits, is an admirable idea. Although we do stock certificated oils, we also have some which are not certificated but are from biologically grown plants; I am not keen to claim these as organic for the following reasons:
1 It is a very expensive process, involving inspectors examining the soil and testing the plants from time to time for fertilizers and pesticides. The certificate-awarding body claim money not only from the farmer, but also at each transaction through to the final one, so the price of the essential oil at the end is rather high. By the way, nitrogen, phosphorus and potassium do not come through in distillation.
2 It cannot be taken for granted that a field of biologically grown plants is always free from contamination. What about acid rain, air pollution, polluted ground water, aerial crop spraying, radioactivity e.g. Chernobyl, etc. – all beyond the control of the farmer?
Nevertheless, for those who (like several of our French farmer suppliers) believe in natural methods, the belief itself has to be the reason for wanting organic essential oils and if these beliefs are serious, it is a pity to have to escalate the price by buying proof, unless it is impossible to sell the crop (or the oils) without it. It may come to this one day, simply because some people will sell oils without certificates, claiming they are organic, when in fact they are not – just like the fruit and vegetable trade!
3 Aromachemistry – the Chemistry of Essential Oils
We are now going to take a look at the fundamentals of essential oils – the structure and effects of their chemical components. I want you to enjoy this chapter, and I hope you find it absorbing and stimulating.
Essential oils can be classified in several ways and if you know the chemical composition of an oil you can make a fairly good guess as to its therapeutic effects and possible hazards. There is no need for me to go into great detail – as my husband puts it, ‘It is quite safe to drive a car without being a qualified mechanic, so long as we understand the simple basic principles of how the car works and we have learnt to control it.’
I shall explain only the basics, very simply and I hope clearly, so that you can appreciate the significance of the components which make up the oils – and their relationship with one another. This way, you will get to know these precious gifts of nature and be able to use them in an understanding and respectful way.
Everything in the world, both living and non-living, is made up of chemicals. Most of the chemistry I learned at school was about things that are non-living and have never lived – this is called ‘inorganic’ chemistry. The chemistry which includes all living things (and those which have once lived) is called ‘organic’ chemistry or the chemistry of the carbon compound, since all organic substances contain carbon. The two main groups of chemicals in organic chemistry are referred to as chain or aliphatic and ring or aromatic (not necessarily meaning odorous).
Carbon, hydrogen, nitrogen and oxygen (this last accounts for nine-tenths of the human body!) are the basic building blocks of life itself, each of them being composed of atoms, the atom itself being thought at one time to be the smallest particle in existence.
Atoms
The building blocks of the universe! Every atom has a nucleus containing one or more protons, which are electrically positive, and one or more neutrons, which are neutral. Around the outside, depending on the particular atom, there are one or more electrons, each of which carries a negative electrical charge. These electrons are whizzing round and round the nucleus, rather like the earth orbits around the sun – ceaseless, never still. See Figure 3.1.
FIGURE 3.1: Hydrogen atom
The electrons orbit the nucleus at various distances from it. To feel really happy, the atom likes to have two electrons in the first ‘orbit’ (called a shell) around the nucleus – the second and further orbits or shells like to have eight.
As you can see from the diagram, a hydrogen atom is short of one electron – oxygen is short of two and carbon is short of no less than four! So each searches for and joins with other atoms capable of sharing electrons and therefore satisfactorily completing the number necessary for its stability. The atom is then content!
A simpler way to represent the ‘discontented’ or unstable atoms is to give them ‘arms’, i.e. – and =. These arms are called ‘bonds’ because they unite one atom to another.
Molecules
Once there are two or more atoms joined together, the group then becomes a molecule and Figure 3.2a shows a complete molecule of hydrogen, sharing the electrons.
You will notice that hydrogen only needs one more atom like itself to become stable. Oxygen, on the other hand, needs two hydrogen atoms to become a stable molecule of water (H2O). See Figure 3.2b. If we give the carbon atom four hydrogen atoms it will become a stable molecule of methane, (CH4) – Figure 3.2c, which is a gas; if we give the carbon atom two oxygen atoms (remember that oxygen has 2 arms) it will become a molecule of carbon dioxide (CO2), also a gas – the one we breathe out (Figure 3.2d).
FIGURE 3.2: a) hydrogen molecule; b) water molecule; c) methane molecule; d) carbon dioxide molecule
The bonds making up the water and the methane molecules are called ‘single bonds’, those making the carbon dioxide molecule are called ‘double bonds’, because there are two parallel bonds. Double bonds give a molecule a certain amount of rigidity, but they can separate fairly easily to provide an opportunity for other atoms to join in and share electrons as we shall see later on.
Now it begins to get interesting! Carbon atoms have a special ability to keep joining with other carbon atoms to form long straight or branched chains. Each time a carbon atom (with two hydrogen atoms) joins the chain, the molecule so formed is bigger and heavier than the one preceding it (see Figure 3.3).
We are nearly there!
FIGURE 3.3: The chain increases by the addition of CH2 each time
Isoprene Units
An isoprene unit is a molecule comprising five carbon atoms in a branched chain and is one of the two basic building blocks for essential oils. See Figure 3.4.
FIGURE 3.4: Isoprene unit
Terpenes
Some terpenes are hydrocarbons, being made up solely of carbon and hydrogen atoms in a chain. Because they are in a chain they are termed aliphatic. Although they are not classed as aromatic, they do have some aroma, and play a part in the therapeutic effect of the whole oil. Perfumers are interested in the individual chemicals within an essential oil and sometimes those oils with a large percentage of terpenes are partially or completely de-terpenated – meaning that some or all of the terpenes are removed from the natural oil (an oil so treated is also known as a folded oil – see fractionation in chapter 2. As already explained earlier in the book, the big essential