Eating with your eyes and ears

As chef Tristan Welch took his pineapple upside down cake off the Naked Scientists' BBQ and let it cool, Katie Haylor spoke to sensory scientist Barry Smith about how vision and hearing come into the world of food...

Chris - Tristan, the moment of truth has arrived. We have to lift the lid on the barbecue.

Tristan - Oh ho ho!

Chris - These look really good!

Tristan - You see they're bubbled up beautifully, and they're perfectly cooked. You can see that crisp on the outside, slightly golden on the top, and if you look on the edges there, they've got that beautiful golden brown colour.

Chris - The man was right and his upside-down cakes have cooked in their tins on the barbecue. We're just pulling them off now. The sausages look pretty good too Tristan. I hand it to you, you cook a mean sausage on the barbecue, even if it is gas.

Tristan - Well, who knows, maybe I'll make a career out of it. I don't know.

Katie - Barry - my mouth is watering in the studio. It sounds really good. But what about sound and sight when it comes to food? Because we've dwelled on smell, and taste, and touch, as you said. What about what food sounds like or looks like?

Barry - All of these things make a difference. I mean, if you think of the colour of food, if the colour is wrong, you don't want to eat it. There was a lovely experiment done by Wheatley in the 1970s where he had people in an ultraviolet room eating steak, peas, and chips, and asked to say whether the steak was tender, how were the chips, how were the peas; they were discussing the food. And then he flipped the real lighting on, and you saw the steak was blue, bright blue; the chips were green; and the peas were red. And some people had involuntary retching. That's funny, because they'd already been discussing and talking about the food. So it shows you that how food looks will have a big impact on whether it's acceptable. And then of course, sound. Interesting, when we're thinking of chefs like Tristan, you're thinking of them using sound to assess their cooking. Does the pan sound too angry? Is the sizzling too high? Do I turn it down? But also, when we're on aircraft, the sound of white noise in our ears - 89 decibels or above - has an impact on the brain's ability to process information from the tongue. So salt, sweet, and sour are reduced considerably, maybe 10-15%. So if you want a better experience when you're reaching on an aircraft, take your noise-cancelling headphones; or eat something with umami, because umami seems to be immune to this effect. And what's got lots of umami on an airplane? Tomato juice, because tomatoes are rich in umami. So that's why people have bloody marys on a plane and at no other time.

Katie - What about just the beautiful outdoors? I mean, Chris and Tristan and Eleanor are outdoors. What about being able to see trees and smell grass and things like that?

Barry - Yeah, I think you're getting all of those wonderful sights and sounds. Remember, some of our happiest memories - especially from childhood, if we had a happy childhood - are being outdoors in summer, having picnics. Those are happy occasions. So the smell of freshly cut grass, the smell of all that chlorophyll; these are odours which remind us of happy occasions. And when you also think of eating outside, you're in a very natural setting, and in fact perhaps we're even reminded of some of our evolutionary ancestors. It was when they were sitting around fires, cooking food for the first time, that they were extending their daylight hours by light from the fire; they were safe from predators; they developed jaws that were not so strong, because they didn't have to have enormous bite strength to eat raw meat; they were getting these new, cooked flavours. So I think there's something almost ancestrally wonderful about watching meat colour and brown and give off roasted aromas. And then we're going to get the flavours we expect and see the smoke passing before our eyes. All of that is part of the experience of eating outdoors and having a barbecue.