Ready for a virtual cocktail...

According to the headlines, thanks to a clever mix of electronics, cocktail glasses of the future will change water into wine and trick our senses into thinking we are drinking anything and everything.¹

Nimesha Ranasinghe², a former researcher at the National University of Singapore has come up with a decidedly imaginative invention that is attracting widespread coverage in online press, in blogs and on social networks: the Vocktail. This glass is capable of transforming plain water into a clever mix of sensations reminiscent of those aroused by a glass of wine or orange juice, or even a mojito.

This may sound like a trick worthy of the greatest visionaries, but this virtual cocktail glass actually stimulates three of our senses. A light-emitting diode changes the colour of the liquid; electrodes on the rim of the glass directly stimulate our taste buds to make us perceive tastes, while a tube releases odour compounds evoking the aroma of the desired drink.³ The idea is to give us the impression that we are sipping on something other than water. Sounds incredible, doesn’t it?

Yet there’s nothing very virtual about it, as the colour sensation is procured by a change of... colour, and the aromatic sensation by the use of... food aromas. The taste sensations are actually the only thing that is virtual, as our taste buds are electrically stimulated without the use of any tasty chemicals. However, while this device may not be all that virtual, its magic lies in the fact that it makes it possible to instantly change the characteristics of the same drink and go, for example, from a mouthful of red wine to a mouthful of mojito. Sounds like fun! Fun, maybe, but limited nonetheless.

Toneless colours

With regard to the visual aspect, a simple LED alters the colour of the transparent liquid to make it look like a drink flavoured with red berries, orange, mint, etc. There’s nothing new about that, as we’ve known for decades that the colour of a drink influences our perception of its flavour⁴, enabling an ordinary white wine to be passed off as a red.⁵ Colour isn’t everything though: The opacity or transparency of a liquid also plays an important role in how we perceive it. This characteristic cannot be modified here, making it impossible to simulate the whiteness of milk or the opacity of a full-bodied Bordeaux. The Vocktail’s use of LEDs to give water a particular colour opens up certain avenues but, rather than it being capable of simulating any drink, the range of possibilities is actually somewhat limited.

Following your nose

When it comes to aromas, the limitations are even more apparent. In fact, as it stands, if we fancied a Vocktail, we would need to have the aromas corresponding to the desired drinks on hand and ready to use: a mojito aroma, one for red wine, another for beer, Coke, and so on. Each in its own reservoir. The prototype has three reservoirs, which allow for a little fun but nothing like the hundreds of drinks imaginable. Ideally, we would need to have a stock of basic aromas which, when cleverly combined, would enable us to recreate the aroma of a real drink. That is far more complex than it seems, and would require dozens of reservoirs, making the cocktail glass significantly heavier. Precise, nuanced blending of each component proves another technological challenge. This idea was already floated at the turn of the 21^st century and start-ups promised the transfer of odours via the internet. This led to significant investments and a big buzz in specialist media and on early social networks, but to resounding flops once launched on the market.⁶ However, research is still ongoing, and it may well be possible, one day. There is still one problem with Vocktails though: Unfortunately they don’t release aromas in the right way. In fact, for the illusion to be convincing, it is important that we don’t just sniff the aroma, but that we exhale it. In other words, the aroma must stimulate our olfactory system by passing through the back of the throat as we exhale (retronasal perception) and not through the front of the nose as we inhale (orthonasal perception).⁷ The effect is not the same; only retronasal perception creates the aromatic sensation of consuming a particular drink. Without it, a beverage may even seem more insipid, as, when we sniff it, we get the impression of a strong flavoured drink, followed by a disappointing void. So it’s a bit of a let-down! One solution, already used in scientific studies on the sense of smell, would be to insert a plastic tube into your nose to deliver the aromas directly to the back of your nasal cavity. But who would want to insert a tube into their nose at a ‘Vocktail party’?

Electric flavours

Probably the most innovative aspect of a Vocktail is that it recreates sensations of taste simply by electrical stimulation of our taste buds. Who has never tried putting their tongue on both terminals of a 9-volt battery and felt a tingly sensation and a peculiar taste?⁸ This electrical taste⁹ is thought to be due to the displacement of ions found in saliva, such as sodium (Na+) and hydrogen (H+). This explains why adjusting the current emitted by the electrode would make it possible to mimic a salty sensation, generally that of sodium chloride (NaCl), or the tangy sensation of the acid compounds releasing hydrogen (H+) ions. It is even feasible that small electric currents such as these could stimulate our taste buds directly.¹⁰ Either way, most research studies mention the ability to evoke salty or sour tastes, but very rarely sweet or bitter tastes. Examining the scientific articles that served as a basis for the Vocktail prototype leads us to a similar conclusion: The only significant sensations this glass simulates are salty and sour tastes.¹¹ Moreover, this device only stimulates the tip of the tongue, which is not comparable to a sensation produced throughout the mouth. This stimulation also stops as soon as contact with the glass is broken (and, of course, we don’t tend to keep our tongues on a glass for long). That is perhaps why Nimesha Ranasinghe and his team are interested in other stimulation devices just as amazing as the Vocktail, such as electronic lollipops¹² or smart chopsticks.¹³

Something for a cabinet of curiosities?

Although far from delivering on all its promises, the Vocktail remains an interesting device, a hallmark of infinite human inventiveness and the desire to explore new possibilities. Is it to be consigned to a cabinet of curiosities, alongside other objects such as a radio hat, tilted glasses for reading in bed¹⁴ or an olfactory alarm clock?¹⁵ Not necessarily. The fact that this invention is creating such a buzz is probably because it piques the interest of a welcoming audience and has the potential for future developments. Be that as it may, researchers in sensory sciences, who are fully aware of the limits of such a device, are looking at it with an amused yet equally watchful eye. After all, we don’t often get the chance to indulge our wildest sensory dreams. But when we do, it feels really good. At the end of the day, the fact that this story is itself virtual is of little relevance.