Professor Charles Spence analyses how the sense of touch can be enhanced in the drinking experience.

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The Midas Touch is the name given to the casual touch on the arm that social psychologists have shown could encourage customers to go with your drink suggestion, not to mention tip more generously should tactile contact occur when the bill is being delivered.

Then, of course, there is the drink itself. Now, unless it comes with a straw, you can pretty much guarantee that the customer is going to pick up the receptacle in which the drink is served before they have tasted your latest creation. The single most important factor is the weight and balance – though all aspects of the glassware (or receptacle) will likely help set expectations in the customer’s mind about what they are about to taste. These expectations anchor and bias the subsequent tasting experience. So my advice is to make sure that it feels like a quality experience.

There is the shape, the texture, not to mention the temperature of the receptacle. It all matters. Across a range of objects, from cutlery to wine and beer bottles and bowls, the general rule is the heavier the better (though finer glassware could come into it). Top chefs know this intuitively, as do, I am sure, many cocktail makers. Of course, the firmness of the receptacle is important too. You would never serve a cocktail out of a plastic glass would you? It would just seem cheap, right? But beyond that it is simply too light and lacks firmness or substance. Even if you know exactly what you have been served, the experience will be lessened somehow.

With regards to temperature, the evidence suggests that the people around you will look just that little bit warmer if you happen to be holding a warm drink in your hand. No, really. This, perhaps, helps to explain why the rocks glass in which I was served a cocktail at the Apothecary Bar came in bubble-wrap. It helped insulate my hand from the icy contents of the glass while delivering an unusual and playful texture. Not soon forgotten, I can assure you.

Causing a stir

Modernist chef Jozef Youssef has been caused quite a stir with his A Taste of Chivas experiences. The same whisky was served in two different glasses – one small, smooth and round, the other larger, angular, and made of cut glass. Often diners suspect that the drinks in the two glasses must be the same, yet they really do seem to taste, and smell, different.

Then, he brings out his Marinetti cubes, opposite sides both covered with Velcro, sandpaper, silk, or some such intriguing material. While it certainly doesn’t work on everyone, there are a fair number of guests for whom running their hand across the different materials really does bring out something different in the drink.

Shapes, as well as textures, influence what people will pick up in a drink and how much they will enjoy the tasting experience. Generally speaking, we find that rounder shapes are more consistent with sweeter tastes, while more angular shapes tend to match bitter and sour-tasting drinks instead.

Here at the Crossmodal Research Laboratory in Oxford, we find the spicy ginger note in a ginger biscuit is rated as more pronounced if we serve the biscuit from a rough plate than from a smooth one. I am sure the same would work with a textured glass. After all, the lips are among the body’s most sensitive skin sites, at least those that are typically available for stimulation in the average cocktail bar.

Given the above, you will now understand why we have been working with Darrol Roberts (robertswineware.com) to investigate the consequences of etching, or ribbing, the lip of the glass for people’s experience of different drinks. While the smoothness of glass is great, surely there have to be some situations in which you just want to deliver ‘a bit of rough’. My guess is that by drawing the drinker’s attention to their mouth in this way, the flavour experience might just be enhanced.

One interesting thing is that, while the texture in the hand can sometimes augment the in-mouth experience, at other times it can set up a contrast. There are few hard and fast rules, but I think that it is something worth experimenting with. So, next time you find yourself behind the bar with a few moments to spare, why not get yourself a few swatches of velvet, silk, and sandpaper, and give it go?

Taste sensations

Finally there is the drink itself. It too will have a certain temperature, a texture, such as creamy, foamy, and it may well impart a certain mouthfeel, such as the astringency associated with young oaked red wine or an overstewed cup of black tea. That sensation of creaminess turns out to be so much more than merely a mouthfeel/texture. Add a creamy aroma to a drink, and people will swear that the texture has changed too. Change the music and it can change the perceived creaminess of chocolate as well.

Touch, then, is rarely just a matter of what we feel, but is often influenced by what is going on with the other senses at the same time. The temperature of the drink matters, though the problem is that the lower its temperature, the less efficiently the taste buds work (hence, for instance, the more sweetness you need to add to deliver the same taste experience).

So, while rarely considered, I believe touch really is so much more important to the drinking experience than most people might intuitively think. A growing body of research shows that the tactile properties of the receptacle can influence the drinker's experience in predictable ways, be it enhancing the perception of quality or accentuating an element of the tasting experience, such as flavour, mouthfeel, taste, or texture.

So, the next time you find yourself thinking about what receptacle to serve your latest concoction in, just remember to make sure that it feels right.