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1. Taste
Can you list all of the basic tastes? There is sweet, sour, salty and bitter, for sure. But anything else? Nowadays, most researchers would include umami as the fifth taste. Umami, meaning "delicious taste," was first discovered back in 1908 by Japanese researcher Kikunae Ikeda. This taste is imparted by glutamic acid, an amino acid, and is most commonly associated with monosodium glutamate, itself a derivative of glutamic acid. Some would be tempted to throw metallic, fatty acid, kokumi and as many as fifteen other basic tastes into the mix as well-though even I haven't heard of most of them. And some researchers query whether there are even any "basic" tastes at all!
The mistake that many people make, though, when talking about food and drink is to mention things like fruity, meaty, herbal, citrusy, burned, smoky and even earthy as tastes. But these are not tastes. Strictly speaking, they are flavors. Don't worry, most people are unaware of this distinction. But how do you tell the difference? Well, hold your nose closed-and what is left is taste (at least assuming that you are not tasting something with a trigeminal hit, like chili or menthol, which activate the trigeminal nerve). So if we struggle to get the basics straight, what hope is there when it comes to some of the more complex interactions taking place between the senses? Taste would be simple, if it weren't so complicated!
Do you mean taste or do you mean flavor (and does it really matter)?
Most of what people call taste is actually flavor, and many of the things that they describe as flavors turn out, on closer inspection, to be tastes. Some languages manage to sidestep the issue by using the same word for both taste and flavor. In fact, in English, what we really need is to create a new word-and that neologism is "flave." "I love the flave of that Roquefort" would do the trick. Let's see whether it catches on. There are also challenges here from those stimuli that lie on the periphery. Just take menthol, the minty note you get when chewing gum: is it a taste, a smell or a flavor? Well, all three, in fact; and it also gives rise to a distinctive mouth-cooling sensation. The metallic sensation we get when we taste blood also has the researchers scratching their heads in terms of whether it should be classified as a basic taste, an aroma, a flavor or some combination of the above.
Most people have heard of the "tongue map." In fact, pretty much every textbook on the senses published over the last seventy-five years or so includes mention of it. The basic idea is that we all taste sweet at the front of the tongue, bitter only at the back, sour at the side, etc. However, the textbooks are wrong: your tongue does not work like that! This widespread misconception resulted from a mistranslation of the findings of an early German PhD thesis that appeared in a popular North American psychology textbook written by Edwin Boring in 1942. So now we have got that cleared up, let me ask, do you actually have any idea how the receptors are laid out on your tongue? No, I didn't think so. Something so fundamental, so important to our survival, and yet none of us really has a clue about how it all works. Shocking, no?
The taste receptors are not evenly distributed, but neither are they perfectly segmented as the oft-cited tongue map would have us believe. The answer, as is so often the case, lies somewhere in between. Each taste bud is responsive to all five of the basic tastes. But these taste buds are primarily found on the front part of the tongue, on the sides toward the rear of the tongue and on the back of the tongue.There are no taste buds in the middle of the tongue. Interestingly, though, many people (including chefs) tend to say that they experience sweetness more toward the tip of the tongue, they feel the sourness on the sides of the tongue and bitterness/astringency often seems more noticeable toward the back of the tongue. And for me, a pure umami solution has a mouth-filling quality to it that none of the other tastes can quite match.
The real question, though, is how have so many people been so wrong for so long? Part of the reason may be due to the general neglect of the "lower" senses by research scientists. Another factor probably relates to the "tricks" that our mind plays on us when constructing flavor percepts, things like "oral referral" and "smelled sweetness" (about which more later). As we will see time and again throughout this and the following chapter, in the mouth, very little is as it seems.
Managing expectations
Why, you might well ask, does a cook-be they a modernist chef working in a high-end Michelin-starred restaurant or you slaving away in the kitchen preparing for your next dinner party-need to know about what is going on in the mind of the diners they serve? Why not simply rely on the skills that are taught in the culinary schools or picked up from watching those endless cookery shows on TV? Why not focus on the seasonality, the sourcing, the preparation, and possibly also the presentation of the ingredients on the plate? That is all you need, isn't it? As a gastrophysicist, I know just how important it is to get inside the mind of the diner in order to understand and manage their expectations about food. It is only by combining the best food with the right expectations that any of us can hope to deliver truly great tasting experiences.
It really excites me to see a growing number of young chefs starting to think more carefully about feeding their diners' minds and not just their mouths. I'm sure this is largely down to the influential role of star chefs like Ferran Adriˆ and Heston Blumenthal, both of whom I have been lucky enough to work with. Where they lead, others surely follow. But that still doesn't answer the more fundamental question of what got the top chefs interested in the minds of their diners in the first place. After all, this certainly isn't something that they teach you at cookery school.
In Heston's case, it all started with an ice cream. In the late 90s, Heston created a crab ice cream to accompany a crab risotto. The top chef liked the taste and, after a little tinkering, believed it to be perfectly seasoned. But what would the diners say? (Typically, any new dish is trialed in the research kitchen across the road from the restaurant. Then, once it has met with Heston's approval-a slow and exacting process-the next step is to try the new dish out on a few of the regulars and see how they like it. Only if a dish passes all of these hurdles will it stand a chance of making its way on to the restaurant's tasting menu.)
Imagine the scene: just like in one of the chef's TV shows, you can almost see Heston looking on expectantly from the kitchens, waiting for the diners' approval as his latest culinary creation is brought out to the guinea pigs sitting at the tables. Surely the diners will think it tastes great, given who made it. But, in this case at least, the response was not what was expected. "Urrrggghhh! That's disgusting. It's way too salty." Well, maybe I exaggerate a little-but trust me, the response wasn't good.
What had gone wrong? How could one of the world's top chefs consider a dish to taste just right only to have some of his regular guests find it far too salty? The answer, I think, tells us a lot about the importance of expectations in our experiences of food and drink. In other words, it is as much a matter of what is in the mind of the person doing the tasting as what is in their mouth or on the plate. When the diners saw that pinkish-red ice cream (this was also evaluated in the lab with a smoked salmon ice cream), their minds immediately made a prediction about what they had been given to eat. Tell me, what would you expect to taste were such a dish to be placed before you?
For most Westerners, pinkish-red in what looks like a frozen dessert is associated with a sweet fruity ice cream, probably strawberry flavor. "Sweet, fruity, I like it, but it isn't so good for me"-all that goes through a diner's mind in the blink of the eye. After all, one of our brain's primary jobs is to try to figure out which foods are nutritious and worth paying attention to (and perhaps climbing a tree for), and which are potentially poisonous and hence best avoided. However, on the rare occasions when our predictions turn out to be wrong, the surprise, or "disconfirmation of expectation," that follows can come as quite a shock. It can, in fact, be rather unpleasant. The diners in Heston's restaurant presumably thought that they were going to taste something sweet, but what was brought out from the kitchen was actually a savory frozen ice. In other words, they were expecting strawberry and got frozen crab bisque instead! The savory ice may have been popular in England a century ago, but it has very much fallen out of favor these days.
In a great series of gastrophysics experiments, Martin Yeomans and his team at the University of Sussex, together with Heston, showed that it was possible to radically influence people's perception and liking of the frozen pink treat simply by changing the name of the dish. All it took to modify the participants' expectations in the lab setting was to tell them that this was a savory ice, or else give the dish the mysterious title "Food 386." The expectations that go with the name or description of the dish led people to enjoy the ice cream significantly more than those who had not been told anything about the dish before tasting it. Crucially, they no longer found it too salty either.
Research suggests that our first exposure to a flavor affects those that come thereafter, even once we know exactly what it is that we are tasting. And though the effects may not always be as dramatic as in the case of Heston's pink savory ice cream, we have probably all had our own experience of this. I still remember, on my first trip to Japan, fifteen years ago, buying a pale-green ice cream from a street vendor. It was a hot spring day and everyone seemed to have one of these refreshing-looking ices in their hands. I had absolutely no doubt that it was mint-flavored, just as it would be back in the U.K. But I recoiled in shock on tasting what turned out to be something most unexpected; it was, in fact, green-tea-flavored ice cream. Delicious in its way, but I must confess that I have somehow never been able to quite get over that initial surprise whenever I am served a bowl in Japan.
Whatever the name and/or description of a dish, and no matter what it looks like, these cues are always there, helping to set our expectations. And those expectations influence our judgments and perception, however subtly. Even when cooking at home, how those you serve experience your food is as much a matter of what is going on in their minds as it is a matter of what they put in their mouths. However, it is not just the color and other visual properties of food that set our expectations.
What's in a name?
Imagine yourself in a fancy restaurant, scanning the menu for something to eat. You already know that you want fish, but which one? Now, let's suppose you came across Patagonian toothfish. Would you order it? No, I didn't think so. Nor, for that matter, did anyone else. Sales of this veritable "monster of the deep" had been disappointing for years. No matter how chefs prepared it, diners just turned their noses up and chose something else instead. Their eyes would continue scanning down the menu, looking for something that sounded, how shall I put it, a little more enticing.
Would the response be different, do you think, if they were to come across Chilean sea bass on the menu? It certainly sounds a lot more appealing, doesn't it? The thing is, though, that these two names refer to one and the same fish! Sales of this currently sustainable fish have increased by well over 1,000%-yes, that's three zeros-in a number of markets around the world (including North America, the U.K. and Australia). The trick was simple: just change the name. This is one of the most impressive examples of "nudging by naming," as the behavioral economists like to call it. In fact, in no time at all, this fish started appearing on the menus of all the best restaurants, a trend that, even today, shows no signs of letting up. Once again, it is what is in the diner's mind, and the associations they make with different labels or descriptions that are crucial here.
The frozen crab bisque/smoked salmon ice cream and Patagonian toothfish cases are exceptional: they have, in fact, been chosen to make a particular point-about the importance of naming to our experience of food. Nevertheless, look around and one finds many everyday examples demonstrating much the same point. Have you ever wondered, for instance, why golden rainbow trout is so much more popular than regular brown trout? The traditionally trained chef's mind may immediately start to ponder differences in taste or texture, or perhaps to consider how the fish was dispatched. But why stop there? When was the last time you ate an ugli fruit (the result of the hybridization of a grapefruit-or pomelo-an orange and a tangerine)? Exactly. You have to wonder how much more popular this member of the citrus family could be had it been given another name. The decline in popularity of everything from faggots to pollack and Spotted Dick in recent years can, at least in part, be put down to their unfortunate names.
Great expectations
Some of you may already be wondering whether you could use the same naming "tricks" to enhance people's perception of whatever food or beverage product you happen to be serving. Unfortunately, though, I very much doubt that you will be able to increase sales of most everyday foods by anything like as much as the Patagonian toothfish-sorry, Chilean sea bass-example might lead one to believe. Nor, unless you have had your head very firmly stuck in the modernist cookbooks, will the colors of the dishes you prepare at home give as misleading an impression of the actual taste or flavor to come as the pinkish-red hue of Heston's frozen treat undoubtedly did. No one will, I presume, get the wrong end of the stick on seeing whatever you might be thinking of serving at your next dinner party. The colors of the foods we prepare normally give a pretty reliable indicator of the probable tasting experience. It is mostly in the modernist restaurant or when in parts foreign that things start to go awry. So relax!
