How to Combine Flavours

A guest post by Mel Barrett

Mel Barrett writes a regular cookery column for the Wholesome Food Association. Mel is a former management consultant who, since leaving the corporate world, has worked with butchers, bakers and canapé-makers (and many others too!) who share her passion for food produced with integrity. She has written/co-written publications for Sustain (the alliance for better food and farming) on bread and London’s food economy, and is currently developing a new kind of cookery course. She has two young daughters. To see Mel’s growing collection of cookery columns, click here.

When I embarked upon the research for this column, I was hoping to come up with a resource that would help the home cook make a quick assessment, night after night, about which combination of ingredients might be thrown together for dinner. The well-read amongst you might remark at this point that I am entering into territory which has already been somewhat charted: books such as Page and Dornenburg’s The Flavour Bible, and Niki Segnit’s The Flavour Thesaurus, with their lists of ingredients and compatible pairings, claim to do just that. But, whilst undoubtedly inspiring, these books are limited in their use. Firstly, there are, by Segnit’s own admission, missing foods. Secondly, ingredients are like instruments in an orchestra: all must have a purpose, and all must be in harmony. I wanted something to make sense of all the components on a plate, not just two.

Food pairing

Aficionados of food pairing think they have the answer. Food pairing is a theory inspired by a collaboration between chef Heston Blumenthal and chemist Francois Benzi, based on the idea that foods work together when they share key aroma compounds. The flavour in our food is provided by a combination of molecules which only the tongue can detect (the five tastes, although scientists believe there are receptors for other substances, including fats); molecules which stimulate the ‘trigeminal’ receptors (e.g. pungent or astringent foods) and aroma compounds, for example, diacetyls (which smell buttery, found in popcorn and lobster) and pyrazines (which smell ‘roasted’, found in cocoa, peanuts and browned foods).

It is the various combinations of these 350 or so aroma compounds which make up an object’s distinctive smell, and its smell which makes up most of what we perceive as flavour (see my columns How to Create Flavour Part 1 and Part 2). Up until fairly recently, the make-up of smells was precious information, guarded jealously by food and perfume companies in secret notebooks and heavy vaults. But now, thanks to technology such as gas chromatography, ordinary people – for a fee – can get an insight into the composition of ingredients (via Leffingwell’s Volatile Compound Database for example, or websites such as Foodpairing). Some unusual combinations have been the result (pork liver and jasmine flower, anyone?).

Not everyone is a fan of food pairing. Harry J. Klee, professor of horticultural science at the University of Florida, whose experiments on tomatoes demonstrate that the link between taste, aroma and the way the brain perceives flavour is extremely complex, puts it thus:

That whole flavor-pairing c**p is just a gimmick by a chef who is practicing biology without a licence. (Drahl, C)

It seems others agree. Wender L.P. Bredie, a professor of sensory science at the University of Copenhagen, believes he has data that proves that the success of food pairing is down to the novelty factor, rather than pleasure inherent in the combinations themselves.

What is the alchemy?

So what, then, is responsible for that alchemy between ingredients, if not matching aroma compounds? To find out I would have to delve into the nature of pleasure itself, and answer two key questions:

1. Why do we find some flavours more pleasurable than others?
2. What is the magical effect one ingredient can have on another, which might increase or decrease this sense of pleasure?

Which flavours do we find pleasurable?

With up to 10,000 smells discernible by the human nose, flavour can be tricky to pin down. To help, almost any industry which trades in smell has its own lexicon. There is the Aroma Wheel ™ for wine, which helps wine buffs articulate, amongst others, various earthy, woody, floral, spicy and nutty notes; as well as wheels for coffee, maple syrup and even Comte cheese. Could it be that some aromas and some aroma combinations around these wheels are innately more pleasurable than others? Some argue no: that – with the exception of certain strongly pungent aromas – all responses to smells are learned.

According to Rachel Herz, cognitive neuroscientist and expert on the psychology of smell, the perception of pleasure is linked to emotions experienced when the smell is first encountered, familiarity, or meaning provided by cultural learning. One example cited to back this up is the attempt by the US military to develop a stink bomb, abandoned due to the impossibility of finding an odour that was considered universally unpleasant across different ethnic groups.

Others argue that humans have an innate preference for certain smells, such as those connected with essential nutrients, for example spices and herbs (many of which have antibacterial or digestive benefits), or those which have been key to our survival and development, in particular the aromas of smoked, roasted or fermented foods. Who hasn’t been seduced by the smell of frying bacon? Similarly, when it comes to tastes, we prefer substances which promise fast refueling in times of scarcity (sweetness and fat), or which indicate the presence of our essential amino acids (umami), to those which signal harm (sour and bitter) or cause pain (although the accompanying release of endorphins means the heat from piquant foods such as chilli peppers can become addictive!).

Conversely, pleasure decreases when the senses are not sufficiently stimulated. This may happen when:

• Insufficient taste and aroma is detected, either because not enough umami, saltiness, acid, sweetness and fat are present (food will lack tastiness or ‘body’), or because the food is low in volatile aroma compounds (e.g. protein or grains).
• Perception declines due to desensitisation (known as ‘adaptation’), which can occur in 1-5 minutes of continuous exposure to a strong taste or aroma. This is perhaps why roast meats with a stock-based sauce, or aged hams and cheeses – all rich in umami – work so well with a balancing taste, for example pungent sauces (horseradish; mint sauce; salsa verde) or sweet accompaniments (think roast pork and apple; lamb and apricot; aged ham and peach).
• There are too many aromas in one mouthful. Australian psychologist David Laing demonstrated that the brain can only recognise a limited number of smells at the same time. That’s not to say that a mix is not pleasant (think of spice blends such as garam masala); rather that the profile of individual aromas will not be discernible.

The power of other ingredients

Understanding the nature of pleasure provides the basis from which we can start to understand the power of different ingredients together. However, a warning should be provided at this point: flavour is complex. And, although happy to wade through details of experiments involving boiling celery and electronic noses, I would hate to be accused of extrapolating without a licence. Nevertheless, there are some fairly objective things we can say. Certain ingredients can enhance or decrease pleasure in the following ways:

1. Modify the perception of aroma

Things should taste of what they are, said Curnonsky, France’s first ever food writer. The following bring out the aromas of special ingredients:

• Sweet substances: Recent experiments have proven that sugars accentuate the mango aroma of mangoes, but good cooks have known for years that sweetness brings out the flavour of sweet foods (think of the historic pairing of mace with potted shrimps, or the more recently adopted vanilla with crab or lobster).
• 

  Photo by SingChan

  Sialagogues: Acid, salt and piquant substances (black pepper, cayenne pepper, ginger) are sialagogues (meaning they increase saliva), which enhances the perception of aroma.

• Aroma enhancing vegetables. It’s not entirely clear how these magic vegetables work, but experiments testing the effects of certain aroma compounds in tomatoes and celery have confirmed that they do indeed intensify the aroma of other foods. According to Witherly, the white and light green alliums do the job too.

Some substances can have negative effects:

• Tannin in red wines makes fish taste metallic
• Sensations which linger (pungent and piquant foods such as pepper, onions and ginger) make aromas which dissipate quickly appear weaker.

2. Modify the perception of tastes

• The aroma compounds of some ‘magic vegetables’ can enhance taste, for example celery intensifies umami, and tomatoes sweetness (see above)
• Using several types of umami greatly magnifies the sense of umami-richness (for example, meat plus mushrooms plus parmesan cheese)
• Sweetness decreases the perception of bitterness or sourness
• Proteins reduce the astringency of tannins in red wine (why tannic red wine is used in sauces accompanying meat, but never for vegetables)
• Piquancy can decrease the perception of sweetness.

Rules for combining flavours

Some concluding thoughts: what I found was that there is no such thing as an inherently bad combination of aromas, and that a match made in heaven is as much due to the associations which lie behind the ingredients as any alchemy between them. You could boil it down to a few rules:

1. Ensure there is lots of discernible aroma, including the top five for extra pleasure (roasted, fermented, smoked, herby or spicy)
   • Keep special aromas separate
   • Use aroma enhancers
2. Ensure umami, salt, sweetness and acid and fat are present in every mouthful, without there being an overall impression of sweetness, saltiness or sourness.
3. Provide richness by using fat and different types of umami, but make sure the richness is offset (by sweetness, pungency or heat in the case of umami, and acid, pungency or bitterness in the case of fat).
4. Link ingredients by cultural association or resonance to the eater.

We don’t need science to prove what many already know: some ingredients do special things to our foods. One day, science may be able to tell us exactly why (perhaps a special eighth taste on the tongue will be found, linking to an undiscovered neural pathway in the brain).

But nothing will change in millions of kitchens across the world. If a culture is making heavy use of a few key ingredients, you can bet they have magic in them (for example, parsley and garlic in classical French cuisine; garlic, ginger, chilli and spring onion in Chinese). The best advice is this: copy them. And to enhance your pleasure, learn a little about the food culture. What are the stories behind the ingredients? What are their customs and traditions? You really will enjoy your meal more.

Bibliography

Baldwin, E.A., Goodner, K. and Plotto, A. (2008). Interaction of Volatiles, Sugars, and Acids on Perception of Tomato Aroma and Flavor Descriptors. Journal of Food Science, 73: S294–S307. doi: 10.1111/j.1750-3841.2008.00825.x

Drahl, C. Molecular Gastronomy Cooks Up Strange Plate-Fellows. Chemical & Engineering News, Volume 90, Issue 25, pp. 37-40. June 18, 2012.

Herz, R.S. (2005). Odor-associative learning and emotion: effects on perception and behaviour. Chem. senses (2005) 30 (suppl 1): i250-i251. doi: 10.1093/chemse/bjh209

Kurobayashi, Y., Katsumi, Y., Fujita, A., Morimitsu, Y. and Kubota, K. Flavour Enhancement of Chicken broth from Boiled Celery Constituents. (2008). J. Agric. Food Chem., 2008, 56 (2), pp 512–516. doi: 10.1021/jf072242p

Malundo, T.M.M., Shewfelt, R.L., Ware, G.O. and Baldwin E.A. (2001). Sugars and Acids Influence Flavor Properties of Mango (Mangifera indica), J. AMER. SOC. HORT. SCI. 126(1):115–121. 2001.

Page, K. and Dornenburg, A. The Flavor Bible. Little, Brown and Company, 2008.

Prescott, J. Sensation and The Senses, in The Encyclopedia of Food and Culture, Gale Group, Inc. (via www.Answers.com).

Robinson, Jancis. The Oxford Companion to Wine. Oxford University Press, 2006.

Segnit, N. The Flavour Thesaurus. Bloomsbury, 2010.

Tortora, G.J. and Derrickson, BH. Principles of Anatomy and Physiology. Wiley, 2009.

Witherly, S. Why Humans Like Junk Food. iUniverse, 2007.

 

Text of this column © Mel Barrett, 2012

Photographs from Flickr used by Creative Commons License as attributed above