Sandpaper and silk: texture and flavour perception

Bitter chocolate textures

Sandpaper and silk: texture and flavour perception

by Jozef Youssef17 November 2015

Chef Jozef Youssef takes a look at how texture can affect flavour perception and the experience of eating.

Sandpaper and silk: texture and flavour perception

Chef Jozef Youssef takes a look at how texture can affect flavour perception and the experience of eating.

View more from this series:

Jozef Youssef on multi-sensory dining

Jozef Youssef founded the collaborative gastronomic project, Kitchen Theory, to explore the multi-sensory elements of eating.

Jozef Youssef founded the collaborative gastronomic project, Kitchen Theory, to explore the multi-sensory elements of eating. An experienced chef with stints at The Connaught, The Dorchester and The Fat Duck under his belt, he has worked with scientists, chefs and artists to further his knowledge in this fascinating area. He is the chef-patron of the Kitchen Theory experimental dining experiences as well as the author of Molecular Gastronomy at Home, a simple introduction to the science behind modernist culinary techniques.

Jozef Youssef founded the collaborative gastronomic project, Kitchen Theory, to explore the multi-sensory elements of eating.

Jozef Youssef founded the collaborative gastronomic project, Kitchen Theory, to explore the multi-sensory elements of eating. An experienced chef with stints at The Connaught, The Dorchester and The Fat Duck under his belt, he has worked with scientists, chefs and artists to further his knowledge in this fascinating area. He is the chef-patron of the Kitchen Theory experimental dining experiences as well as the author of Molecular Gastronomy at Home, a simple introduction to the science behind modernist culinary techniques.

For the penultimate article in my series on multi-sensory dining, I am tackling texture. This may well be the shortest article of the five because, of all the senses considered in relation to gastronomy, touch (along with sound) is one of the least researched. This is mainly due to the fact that conventional definitions of flavour do not include texture. But how important is the role of texture in experiencing flavour?

Does texture matter?

Let’s start out with something very simple to help us answer this question; what makes a crisp, a crisp? Think of your favourite crisp brand. Flavour will factor into your choice, but is that all that makes them your favourite? For many, it is the size, thickness (or thinness) and the mouthfeel – the crunch in the mouth (which also belongs in the sound domain) – which, along with a particular flavour, make up the characteristics of their favourite crisps. Dare we say the texture, weight (and sound) of the packet itself may even be a characteristic which endear us to our favourite brand?

Think about throwing all the elements of your next Sunday roast in a blender before serving it to your family and friends. If texture was irrelevant to flavour, those beautiful crispy potatoes, rare beef, perfectly cooked vegetables and home-made gravy would be just as delicious after a good blitz. Clearly we have certain associations, perceptions and preferences for the physical attributes of food which go beyond just how they look and taste.

So far so simple. Everything I have mentioned above is hardly mind blowing, nor is it really that experimental, but it is important to highlight the role that texture plays in the simplest terms. I’m now imagining that perfect crème brûlée with a glass-like sugar disc waiting to be shattered into velvety custard. The texture is a big part of what makes it a great dish – a disappointing top equals dissatisfaction.

The contrast between the caramel disc and custard proves how important texture is.
For one subject, chicken was only ready to serve when it felt 'pointy'.

Synaesthesia

When researching for our last dining concept, Synaesthesia by Kitchen Theory, I read a book by Dr Richard Cytowic (who collaborated with us in the development of the dinner) and I came across research on a synaesthete called Michael Watson. This man was unique; as well as other interesting forms of synaesthesia, he had a very interesting and rare form in which foods in his mouth generated actual tactile sensations in his hands! As he ate food, he would feel different shapes, weights and textures in the palm of his hand. Watson had different tactile sensations for all kinds of tastes – spearmint, for instance, gave him a feeling of running his hand along a tall, cool column of glass or marble and chicken was only ready to serve once it felt ‘pointy’, like placing his hands on a bed of nails. This obviously got me thinking about this link between taste and external tactile stimulation and I turned to science to explore this link further.

Here’s a question for you: do rough textures such as sandpaper match better with salty, bitter notes or sweet, creamy notes? And how about soft textures such as velvet? Which of the tastes mentioned would they work with? For most people, it makes sense that rough textures match salty/bitter notes and the softer textures correlate to sweeter/smoother notes. The question now becomes: can external tactile stimulation in the hand actually accentuate a diner’s perception of different notes in a dish?

Marinetti’s cubes

To test this concept, we developed a dish intended as an homage to Filippo Tommaso Marinetti. Marinetti is known best as the author of the Manifesto of Futurism which he wrote in 1909 and The Futurist Cookbook published in 1938. What made futurist cooking so revolutionary was that it drew on food as a raw material for art and cultural commentary reflecting the futurist idea that human experience is empowered and liberated by the presence of art in everyday life. Marinetti saw food as the ultimate promise of optimism – a gateway to sensual freedom. He also very much advocated the idea that guests should run their fingers over various textures in order to augment the mouthfeel and even flavour (and intensity) of the elements in a dish. This inspired our Marinetti Cubes which are black (to remove colour cues); seven inch cubes with each of the sides covered in a different textured material – natural wood, velvet, plastic, Velcro (both sides), and sandpaper.

Amazingly enough we found that some of our guests did genuinely perceive differences in the taste and mouthfeel of the dish, based on the textures they ran their fingers over on the cubes. The textures affected around twenty percent of our guests, five percent of whom had pretty strong reactions (which include the guest who got ‘cotton mouth’ from touching the fuzzy side of Velcro; a table of two who couldn’t stop commenting on how much saltier the dishes became once they touched the sandpaper and my favourite, the guest who had to touch the velvet side of the cube to get through one particular dish because she felt the rough textures made everything too crunchy and noisy!) We are so interested in this idea that we have included the texture cubes in our latest experimental dining concept Mexico by Kitchen Theory.

Wider implications

If tactile sensation can be used to enhance taste and flavour, there could be practical applications. How about channelling this research towards our growing concern with high sodium levels in processed foods. Given the ability of rougher textures to enhance saltiness in a dish, simply eating with a slightly grainy textured spoon might allow us to reduce the salt in our diet without even noticing its absence. Could we find a way to cut back on sugar using a similar idea? Silk-covered chocolate mousse pots, for example. Plenty of chocolate companies use silky textures in their television and print ads to plant the idea in our minds that their product is smooth, creamy and sweet. This is just taking that concept to a more physical level.

Crockery and cutlery

Also on the topic of texture, let us not forget our cutlery, crockery and glassware. Does a Michelin-starred meal taste better with heavier cutlery? Apparently so. The team at the Crossmodal Laboratory in Oxford conducted an experiment with more than 130 diners at a hotel restaurant in Edinburgh. The results showed that simply using high-quality cutlery normally reserved for banquets resulted in customers willing to pay fifteen percent more for their food, compared to people eating the same meal with lower-quality utensils. And as for glasses, just think about how much more pleasant a good wine, Scotch or brandy tastes out of the right glassware.

Kitchen Theory at home

Much of what I have discussed in this article is intuitive, but it is worth paying a little more attention to textures when cooking and entertaining at home. Here are some ideas for bringing texture into your own kitchen.

Food

Textural balance on the plate is vital. Think of that perfect crisp caramelised sugar on the crème brûlée, the charred surface of a roasted piece of meat with a smooth creamy mash and slow roasted garlic, a crusty piece of country bread with a soft French cheese and a chunky fig chutney. Be mindful of the balance of textures within each dish in order to stimulate and pique your guests’ interest at different points within the course. Baked or fried fish, chicken or duck skin is perfect for adding crispy texture as are baked Parmesan or chia crisps and dehydrated purées.

Linen

Introduce a variety of fabrics with tablecloths and napkins. Perhaps try different textured napkins to accompany different courses?

Plates

Smooth, round, ridged, angular; what best fits the dish you are serving on it? For example, rustic, Nordic-style dishes look great on a piece of bark.

Cutlery

Research would suggest heavier is better! But bear in mind there needs to be continuity, your nice minimal crockery may not look great with clunky, heavy cutlery.

Texture cubes

Take a leaf out of our book and fabricate your own version of the texture cubes. Even different swatches of materials stuck on a small card could potentially work. The point is to give guests something to play with and see if you get any reactions. This isn’t an exact science… yet!

Plenty of chocolate companies use silky textures in their television and print ads to plant the idea in our minds that their product is smooth, creamy and sweet. This is just taking that concept to a more physical level.

Jozef Youssef