Savour the flavour
How the brain shapes your taste
New Zealand has come a long way in a short time in the international foodie stakes. I remember the 1970s when one of my mother’s friend’s idea of a bolognese sauce was a block of mince tipped into a frying pan – simply that, not even a sprinkle of salt for seasoning.
Now of course New Zealand is fantastic at producing great taste experiences. We can teach the French and Italians a culinary thing or two. And so we should if food and drink is how we expect to make much of our living for the foreseeable future.
Which makes one wonder about the secrets of taste. What is the psychology behind flavour?
Coffee seems an obvious place to start. We grow no beans and yet for some reason New Zealand has developed a proud and passionate national obsession.
Check the supermarket shelves and beyond the blends are the single origin grindings with lovely names like Brazilian Fazenda Nossa, East Timor Maubesse or Guatemalan Guaya’b. People have their furious debates about which method of brewing is better – Aeropress or Chemex.
So to speak to some experts, I call in on Nick Cowper who runs Christchurch’s Hummingbird Coffee with his brother Tim.
The pair began almost as schoolboys when their dad bought the business in 2000. Now they have grown it to be one of the country’s largest specialty producers, joining Bell Tea’s BrewGroup this year to continue its expansion.
First I confess to Cowper my own personal coffee brewing method might seem heathen.
After years of mucking about with plungers and paper filters, now I simply spoon espresso mix into a cup, add boiling water, and stir – just like instant. The sludge sinks to the bottom and the thick froth left at the top is the best bit.
Cowper tells me the technical term for this is steeping. And the froth is the crust. Immediately I feel rather more sophisticated.
However soon I discover that I hadn’t really been thinking about flavour creation from a food manufacturer’s perspective.
It is a little disappointing when Cowper says there are no shortcut sensory tricks to producing a taste experience. Much of his and his brother’s job involves travelling the world to source the best possible beans. ‘‘It is the basic quality of the bean that you taste.’’
On the counter in Hummingbird’s cupping room are a row of moisture readers and other lab instruments. Tim is about to check the beans for the day’s batch of roasting with scientific care.
Cowper says it starts with a visual inspection of bean quality – no weevils or deterioration. But you want ‘‘gingers’’, the surface flecks that show the crop has been naturally sun dried and so developed some taste-complexity.
And then of course there must be quality control right through the whole process. Freshness is everything, so soon as the beans have been roasted, ground and bagged, the boxes are on their way to the supermarket or cafe.
‘‘We deliver six days a week to the stores. And it’s there overnight. So while we’ve really grown as a company, we focus on producing little and often. We still hand-pack and hand-tag everything.’’
Even the roasting and blending is largely directed at creating product consistency, says Cowper.
Yes, there is a coffee house’s art. What turns people on is the intrinsic complexity of coffee’s taste. When browned the right amount, a green bean releases a cocktail of chemicals.
There are the enzymatics that are fruity and floral, the maillard compounds that are nutty or malty, the sugars which are vanilla and chocolate, the dry matter which is ashy or smoky.
And every coffee tree reflects its particular environment – its terroir – just like a grape vine. ‘‘Last year we had this beautiful naturally-processed Yirgacheffe bean from Ethiopia. We termed it berrylicious because it was just so fruity and full-on.’’
Cowper says most drinkers would find a single origin variety like this over-powering – too much of a novelty. So the goal of blending is to mix a number of such distinctive notes to create a rich 3D flavour experience.
The balance has to tick the box on a number of dimensions like body, acidity, and finish. And it also has to wind up having a strongly identifiable character.
‘‘It is like a craft beer or a malt whiskey. There has to be a depth, a complexity. And it has to be really memorable as well.’’
We seem to be tapping into one of the psychological secrets – creating memories. Didn’t Proust write a book about that?
However Cowper adds the blender’s skill still works mostly the other way round than you might expect, because a coffee house’s problem is that its raw ingredients are never exactly the same from one harvest to the next.
Being a natural product, the beans are always affected by the growing conditions. And suppliers come and go.
Floods in Uganda wrecked most of its crop last year. Cowper says for a while Panamanian farmers were new and striving hard for quality, but with success their efforts slackened off.
So instead a blend starts with a careful note of a style – Cowper says you can’t even preserve reference samples because the flavour dies – then there is a business of reproducing that taste formula for the supermarket shelves.
Cowper points to the samples of beans on the bench that currently compose Hummingbird’s Nectar blend – a name inspired both by an after-work nip of Glenmorangie malt whiskey, and also what Hummingbirds like to sip from
‘‘It is like a craft beer or a malt whiskey. There has to be a depth, a complexity. And it has to be really memorable as well.’’ Nick Cowper who runs Christchurch’s Hummingbird Coffee with his brother Tim
flowers, he says.
‘‘We wanted a Central American style – something soft, floral and acid, with no pointy edges.’’
At the moment, that is a mix of three beans from Ethiopia, Brazil and Costa Rica. But the proportions and roasting times might have to be adapted to either flatten off or highlight various flavour elements, depending on the pungency of this year’s supply.
And Cowper says sometimes there are complete substitutions, or five kinds of beans might be needed instead of three.
A big part of the psychology of taste is giving customers what they expect. It is not enough just to be memorable, he says. A premium product has to remain true to that carefully constructed memory.
This business of manufacturing great taste experiences is turning out more complicated than I expected.
Next I call up two food scientists at Otago University, sensory psychologist Dr Mei Peng, and Pat Silcock, manager of the product development research centre.
Silcock laughs guiltily when I mention coffee as a prime example of the rapid development of the nation’s palate.
‘‘I’m in the unfortunate position that my own coffee experience has also evolved over time. Now noone’s beans are good enough for me anymore. I’m facing having to learn how to roast my own beans to meet my standards,’’ Silcock confesses.
But getting down to what science knows about taste, Silcock says a misconception is that it is our simplest and most primitive of senses.
Silcock says it does start in a simple way with the taste buds – the chemical receptors which stud the tongue.
We have only five kinds of those to detect sweetness, saltiness, sourness, bitterness and umami – the pleasant meaty savouriness which is often associated with luxury products like pate or cured ham.
‘‘There’s some discussion now about there being a sixth taste for fat – for fatty acids. But opinion is mixed on that,’’ Silcock says.
The evolutionary logic for each of these receptor types is clear. Silcock says babies are born pretty much with just the one preference – sugar. Sweetness signals a high energy source. And human breast milk is particularly sweet.
‘‘It’s got a lot more lactose in it than cow’s milk. And you really have to start off with a liking for your mother’s milk – the population’s doomed if you’re already a picky eater at that stage.’’
A taste for salt develops later in infancy with exposure, says Silcock. Likewise, bitter and sour are at first disliked in a general way because they are a possible sign of the toxins plants use to defend themselves, or that something is fermenting and going off.
Yet life experience eventually shows broccoli and brussels sprouts are healthy to eat. Fermented products – when humans are in control – are part of the appreciated variety of what we can eat.
And umami is a signal of the amino acids – like the glutamate in monosodium glutamate – being released when protein is chewed. Again an evolutionary reason for a positive association, Silcock says.
So the mouth is set up to decode the essential nutritional value of whatever we put into it. Then of course, our nose – with its many thousands of different chemoreceptor types – continues the analysis as food’s volatile elements get airborne.
Silcock says there is a difference between odour and aroma. Just sniffing smells – a rose or furniture polish – is one thing. But when eating, aroma and taste become a subtly fused experience.
And the biggest impact with most food is not due to inhaling but swallowing – the ‘‘swallow-breath’’ which forces a concentrated blast of volatiles up the back of the nose as a mouthful goes down.
‘‘The strongest perception is then. You have a much bigger surface area exposed when the back of throat is being used as well.’’
A craft beer enthusiast as well as a coffee lover, Silcock says that is why beer tasters drink rather than spit like wine judges. ‘‘Swallowing is the important part with beer as that is where its bitterness comes out most.’’
However psychologically, taste and aroma are still just the beginning. Chipping in, Peng says from a sensory science point of view, it has become apparent that flavour is a complete state of experience. The mind is forming an image, an intricate memory made up of everything happening.
It may sound ridiculous, she says, but research shows drinking coffee in a brightly lit room makes it taste more bitter than exactly the same brew in a dimly lit one. Perhaps cafes ought to adjust what they serve to match their decor?
Mouth texture obviously is central to the experience of food. But so is the sound of its eating. Potato chip makers have to tune their recipes to create a signature snap at the moment they are being broken and their taste first released.
Peng says this is a reason for food rituals – the special cup we use, the sense of occasion we create. These are all extra sensory ingredients that frame our state of perception and so constitute a proper part of a flavour experience.
Silcock says the multidimensional nature of taste means that congruency, or sensory predictability, is a key requirement in creating a successful food product. We all hate surprises when it involves something going in our mouth.
‘‘Everything has to go together. If you see a lovely apple that smells good, has a nice colour, but you bite into it and it’s mealy, or its incredibly sour, then the perception doesn’t meet the expectation and it’s huge disappointment.’’
Silcock says researchers have tested people with meat-flavoured ice cream. If the subjects were warned, they might not like the ice cream particularly, but at least they didn’t gag like they did when given a spoon and anticipating a sweet taste.
So as with coffee blends, Silcock says food manufacturers may be in the business of selling product memorability, but that in turn puts a premium on being able to repeat the sensation.
It is why the New Zealand apple and kiwifruit industries have spent fortunes on developing export varieties that look how they taste.
It is why there are national-scale uproars whenever a manufacturer changes its factory location, or alters its ingredient mix, causing any kind of change in a familiar product line. Remember the howls about Marmite, Milo, Griffin’s Gingernuts, and a hundred other such instances?
Part of Silcock’s work is to help companies get it right. He says an Italian cereal bar maker recently had the problem of producing a low-sugar version of its range.
‘‘That changed the structure of the bar, which changed the timing of the release of the flavours. It broke up too fast in the mouth and so there was a need to compensate for the sugar removal with a compound that would break up the same way.’’
Using a glass tube poked up the nose of test subjects, and drawing off the swallow breath to analyse its chemical composition with a mass spectrometer in real-time, he was able to identify the aroma molecules that mattered and when exactly they were hitting the nasal cavities as people chewed.
Yes, the science of taste is getting that getting that sophisticated, Silcock says.
One last person I wanted to speak to was Professor Richard Archer of the Massey Institute of Food Science and Technology in Palmerston North.
His shtick is 3D printed food. What the heck kind of futuristic taste experiences is that going to give us?
Archer says the short answer is we don’t know yet. The team’s funding ran out before it could get into flavour production.
The project only got as far as creating a white and tasteless base material, a starch and polysaccharide batter, that could be deposited ‘‘pixel by pixel’’ in rice-grain sized blobs to build up a shape.
The next step would be to add the flavours and colours to the batter to make something you might want to eat.
Archer says he can only guess at the potential to produce something surprising.
‘‘You would be able to put really different flavours side by side. There’s no point making an analogue of a pizza – a real pizza is always going to be better than a 3D printed pizza.
‘‘But it could be a completely new food form with the juxtapositions you could create. Who knows what it would taste like if you put hot chilli beside menthol, beside dark chocolate?’’
Archer can imagine it as a fast food craze. Kids would dial in their own designs on an app. And already commercial 3D food printers are beginning to hit the market.
The 3D food printing researchers are also talking more nobly about using the technology to help solve any future world food shortage.
If powdered insects or seaweed could be used as a source of cheap protein to be woven into more attractively textured and coloured products, that could become big business.
But stop. Sorry, I’m beginning to lose interest right there. Too much information. It is reminding me again of my childhood horror at being presented with a plate of spaghetti topped with naked mince. The incongruency is mounting too fast.
Time instead to grab that bag of single origin special brew Cowper kindly left me with – something earthy and winey from an organic farmer’s co-operative in Ethiopia.
Let it steep in my special mug and form a crust. Ah, the joy of flavour experiences.
There’s no point making an analogue of a pizza – a real pizza is always going to be better than a 3D printed pizza.’’ Professor Richard Archer of the Massey Institute of Food Science and Technology in Palmerston North