Although the idea of chemical flavourings is well known, individual chemicals that add a particular flavour to a food rarely exist in pure form.  For example, a lot of things that smell quite nice taste disgusting.  It works the other way around as well: chloroform, for example, has a wincing smell that is cold to the touch, and heavy to lift and carry.  I did not think much of it, but from the screams and dramatic throes of every other victim in Agatha Christie novels, I was never sure I wanted to get close.  However once in the laboratory as a postgraduate I breathed it in by accident, onto my tongue, and found it tasted quite sweet.  Conversely, molasses for animal feed smells delicious, rather like treacle.  I am reliably informed that the taste of this feed fails to match its odour however.  The evidence for this was a fit of vomiting by a friend who dared, one cold Sunday morning, to taste the molasses used in her horse’s breakfast.

Flavour Options

The traditional reason that chemical flavourings have not assumed a big place in food manufacturing is that we can flavour food with herbs and spices, and have done for probably thousands of years.  These, however, are not flavourings as chemists would understand them.  The flavour of nutmeg, cinnamon or tarragon, are the result of a variety of compounds present.  Indeed, several may be shared between any two flavours.  Generally, known flavours like tomato or cranberry are not supplanted directly into foods, but chemicals that enhance the flavours can be used on top of ingredients that are already there.  We use many of these flavour enhancers without thinking about it.  Sugar, salt, lemon juice, vinegar and mustard are all ordinary kitchen ingredients but good enhancers of flavour.  Of course they can be flavours on their own, but are often used simply to enhance flavour.  Thus in putting the flavour back into our cooked carrot for selling on, we might add a little sugar and/or salt to do this.

The Colour-Flavour Confusion

Like our colour perception, our flavouring sense is also fallible.  For example, if you buy strawberry jelly from the supermarket, and make it up according to the instructions, it will be a nice red colour (as we expect, it being of the strawberry persuasion), and smell sweet and fruity.  Most of us will dive into eating it quite happily if we are hungry.  However, if you stop for a second and compare the smell of said strawberry jelly to the smell of fresh strawberries from the same supermarket, both the smell and flavour are rather different.  Fresh strawberries actually have little smell most of the time and taste quite sour.  The sourness is why we add sugar to them – to make them palatable.

This is the basis for my demonstration of strawberry jelly, which we started above with the analysis by colour.  I split the audience up into four groups, giving them one each of the jellies, one red, one orange, one blue and one green.  They are to smell the jelly and decide without saying anything, whether or not they think they have the strawberry one.  The response is different every time.  However, as well as all of them having ‘the strawberry jelly’, none of them do.  What we observe, is that it is strawberry flavouring, and not real strawberries, that are used to make it.  This has been exploited in some creative ways.  One of Heston Blumenthal’s more famous dishes is an orange and beetroot jelly.  There are two blocks – one is red and one is orange.  However blood orange is used so that the orange-flavoured one looks beetroot coloured, and paprika beetroot is used so that the beetroot-flavoured one looks orange.