Having conducted a few tastings, I can safely say that anyone is capable of identifying flavours.

There are no right or wrongs in what flavours you personally find and how you identify with them. However, there is some science behind some very specific tastes. More specifically, there are flavour components that can be found in a whole variety of foods – a selection of these are known as terpenes.

Terpenes are a class of naturally occuring organic compounds which are abundant in the essential oils of plants. Essential oils being found in the “gummy” stuff exuded by plants and trees. Terpenes are also contributors to red, yellow and orange pigments. [encyclopaedia Britannica].

An organic compound is virtually any chemical that contains carbon; terpenes are molecules made up of 5 carbon atoms bonded to 8 hydrogen atoms in multiple chains (the smallest “monoterpene” is C10H16). They are often strong smelling compounds – monoterpenes are the most volatile, that’s why they give off fragrance.

When I first became aware of their existence I immediately made the connection with turpentine: the cleaner is made from pine resin, from which came the name. Terpenes can also be found in certain insects and butterflies, who use secretions with smell to deter predators. It also has an affect on some of their other development and behaviours.

In terms of the flavours that you will come across, Anethole is a terpene with an extra oxygen bond. It is an aromatic compound found in anise, fennel, sweet cicley and licorice.

Limonene, which has the taste and aroma of lemon peel, can be found in pine, hops, cannabis, and, as you may guess, citrus fruits. Therefore when drinking a gin made with pine needles people could suggest that their gin reminds them of grapefruit, or in a beer tasting, they might say a hop forward beer reminds them of cleaning fluid (limonene is in cleaning fluid).

Humulene is the terpene that gives beer that “hoppy” aroma. Myrcene, “the wonder terpene”, is found in overripe mangos, verbena, lemongrass, hops and wild thyme. Caryophyllene, you may have smelt in clove oil, rosemary or ylang-ylang.   Linalool is the lavender scented terpene, a scent that can cheer us up by amplifying our serotonin levels.

Pinene, the chef’s favourite, is found in lime peel, grapefruit, juniper, and in spruce tips. Indeed, if you have wandered through a forest that contains more than its fair share of spruce trees you may well have caught a whiff of pinene – moreso during springtime when the tips are growing in abundance.

And if you are lucky enough to find yourself sitting under a tree in a spruce forest in the spring you may start to ponder if a tree thinks or acts in any way to change its environment (and I quite understand if you don’t). But if you do, then you’d be as well to look at the terpenes that the tree creates for answers.


The blue ridge mountains

Terpenes were once thought to be the tree’s natural defense mechanism against insects as high doses of terpenes can be enough to kill humans let alone insects.

Yet, terpenes may also have a secondary function as they help the trees water themselves. Yes, read that back – they help trees water themselves. You see, we know terpenes are very volatile, they rise up from the trees, bonding to oxygen molecules and free radicals which can also be found floating about high above the trees. Once up there the three get together and form a party also known as an aerosol. These aerosols then get together with more aresols, forming a bigger party of aresols, and eventually forming clouds. Clouds formed in this way are much brighter and whiter when compared to clouds above cities, clouds that bond with pollution molecules rather than terpenes. You may have seen these clouds or have witnessed the terpenes in the air. If you have ever seen a blue haze over a forest it is the aerosols being dispersed by the sun – the most famous of which would be the blue ridge mountains of Virgina. These mountains are littered with conifers and therefore packed full with terpenes.

Whilst on the subject of alternative ways of thinking about intelligence, it may surprise you that understanding sound or interpreting what you see are not the keys forms of communication on this planet, far from it. Terpene communication looks like it might be the prime form of sub-terranial communication.  If you are small and have no eyes or ears then smell is the best form of communication – and key to those smells are terpenes. A plant’s terpenes can be very similar to the development hormones of the insects that prey on it, which then has an effect on those insects  [see Britannica again].

In addtion both bacteria and fungi use them to communicate with. In a study by a group of researchers at the Netherlands Institute of Ecology they concluded that bacteria and fungi respond to each other , they communicate and they can do so across great distances. Group leader Paolina Garbeva explains further, “Serratia, a soil bacterium, can smell the fragrant terpenes produced by Fusarium, a plant pathogenic fungus. It responds by becoming motile (becoming mobile/moving) and producing a terpene of its own.”

So the next time you smell some lavender, wander through a pine forest, or drink a heavily hopped beer, you might want to give a moment’s thought to what is actually going up your nose. You could just be about to drink a plant conversation!

Further reading:

Learn more on the terpenes we enjoy consuming from the following articles;

The leaf online talking about medical applications of terpene caryophyllenen http://theleafonline.com/c/science/2014/10/terpene-profile-caryophyllene/ 

Encyclopaedia Britannica  https://www.britannica.com/science/isoprenoid#ref1002598 

Chemistry infographics http://www.compoundchem.com/?s=terpenes 

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