Sunday London Times
12-3-17

Gastrophysics: The New Science of Eating by Charles Spence

Hold your nose, and you can’t tell red wine and coffee apart. How our perception of food is shaped by all our senses, not just taste

Review by James McConnachie

It is an unusual book that makes you put it down, go to the kitchen and bite experimentally into a raw onion. But Charles Spence, a professor of psychology at Oxford University, is the man behind some of the most playful research in food science — and his delight in weird food facts is infectious.

The extraordinary point of the onion test is that it is hard to tell the difference between onion and apple if you hold your nose. The same is true for red wine and cold coffee. That is wonderful in itself, but it also makes a bigger point — and one that drives this fascinating book. Our perception of food, insists Spence, is shaped by all our senses, not just taste.

Chefs are exploiting this multisensory research in exciting ways. They are using flavoured smoke to deliver concentrated vapours to dishes, and experimenting with ambient aromas, most notoriously the gin and tonic mist concocted for a bar by “food artists” Bompas & Parr. Spence has long collaborated with Heston Blumenthal, at whose restaurant, The Fat Duck, diners ate a seafood dish while wearing headphones and listening to the sounds of the sea. This isn’t just musical wallpaper: it actually enhances the sea-saltiness of the food.

The big food and beverage companies have been quick to see the potential. In 2013, PepsiCo applied for a patent to embed scented capsules in their packaging, to compensate for the lack of aroma delivered by a soft-drinks can. Spence himself is famous, alongside his work with Blumenthal, for the “sonic chip” illusion. His experiment amplified through headphones the higher-frequency sounds as a volunteer bit into a Pringle, proving that you can persuade someone that their crisp is crunchier and fresher if it sounds that way. That research won him an Ig Nobel prize, a parody award for achievements “that first make people laugh then make them think”.

Crisp packets are made to be noisy, for the same reason — it persuades us that the contents are crispier. Supermarkets have long wafted the scent of baking bread, but “sonic seasoning” is now used to nudge our purchases, too. Or more than nudge. If a supermarket plays French music, you might expect a few more shoppers to choose French wine. But according to one survey, when French accordion music was played, 77% of shoppers bought the French wine on offer and 23% the German one. When the music was switched to a bierkeller band, the percentages were practically reversed. It is a dramatic difference.

Touch and sight are hard at work, too, every time we sit down in a restaurant. Luxurious fabrics and carefully chosen colours not only give a general sense of superiority, they influence our perception of tastes. Adding pinkish-red colouring to a drink makes it tastes sweeter, even if it isn’t, while an orange cup enhances the chocolateyness of a hot chocolate and a red plate makes you eat less than a white one. Food seen in motion, oddly, is particularly attractive to us. The slow-melt seen in Marks & Spencer’s famously erotic “this is not just a chocolate pudding” advert is thought to be one of the reasons that sales increased by a reported 3,500% — presumably over a short period, though Spence unfortunately doesn’t say.

As for touch, you can now buy textured spoons that Spence is hoping might enhance particular tastes or flavours — research is apparently in progress. The author himself once hosted a “lab dinner party”, he tells us, at which the guest chef wrapped the cutlery in rabbit fur.

He has also experimented on the effects of using heavier and lighter knives and forks. Surprisingly, diners using weightier cutlery not only think the food is better, but also that it is “plated more artistically” — and they are prepared to pay more for it. The “toy fork” effect is one of the many reasons that airline food tastes awful. That, and the arid atmosphere that dries out the lining of the nose and depresses that crucial sense of smell. Blumenthal apparently recommends a nasal douche before starting your airline meal. You could also try leaving on your noise-cancelling headphones while you eat, as the constant roar of the engines suppresses our ability to taste. Perception of sweetness is especially affected, but other tastes survive high-altitude catering better.

This might explain the bizarre finding that tomato juice is found in 27% of the drinks served on board planes — it is even ordered by people who never normally touch the stuff. Tomato juice (and the Worcestershire sauce in a Bloody Mary) is rich in umami, the so-called fifth taste. And our perception of the intensity of umami, uniquely among the tastes, is actually increased by high levels of background noise.

One of the pleasures of this book, as with molecular gastronomy, is in the creative extravagance of the technology. But there is a fine line between what is fun and ridiculous, exciting and vulgar, and luxury culture (including “fine dining”) sometimes blunders across it. You might quite fancy an “anti-griddle”, which can flash-freeze any food you put on it. You might be entertained by Riedel’s limited-edition champagne glass, which comes with a porcelain cap designed to amplify the sounds of bursting bubbles. Or by Bompas & Parr’s £57 baked-bean spoon, which incorporates an MP3 player and transmits sound through your jawbone, so you can season your chilli-flavoured beans with Latin samba or barbecue- sauce ones with the blues.

I found it harder, though, to smile at the Spanish restaurant that served grilled lemons with shrimp and patchouli on an iPad displaying crackling flames. Even Spence, who is clearly an upbeat sort of person, fails to warm to the new “digital lollipop”, which delivers a mild electric shock direct to the taste buds to stimulate certain tastes. Mostly metallic ones. “You should be electrocuting their nostrils instead,” he comments — taking us back to the idea that smell is the primary sense in our perception of flavour.

I yearned for more scepticism of that sort and more hard science. The title “gastrophysics” is a bit misleading, as this book is really about food technology, psychology and marketing. And while Spence is an engaging writer, and a top specialist in his field, at times he feels too close to the food-and-beverage industry — which indeed largely funds his Crossmodal Research Laboratory. The theatrical trickery of a modernist chef is one thing. What can be hidden in your box of cereal is, perhaps, another.

It is fun to bite an onion, in other words, but less fun to be sold one that you thought was an apple — and that is clearly where the food corporations are heading.