Face To Face With A Wine Tasting 'Electronic Tongue'

Nov 18, 2015

Food scientists at Washington State University have an unusual new partner to help them evaluate drinks, medicines and sweeteners. It's called the "electronic tongue.”

In the latest application, a research team at Washington State University is collaborating with Ste Michelle Wine Estates to study sugar and carbonation in sparkling wine -- specifically how sweet and bubbly to make your bubbly.

A traditional way to approach this is to serve sparkling wine with different attributes to a tasting panel. I was among more than 120 volunteer tasters in this study at a sparkling wine tasting in Pullman, Washington.

I was asked to rate the aroma and then the taste. After four samples I have to take a break to rest my palate, and after seven wines I'm done. But in a lab two doors down the hall, a robot taste tester can analyze up to 20 samples at one sitting.

A $90,000 tasting machine

Professor Carolyn Ross ordered this $90,000 ‘electric tongue’ for her lab in the School of Food Science. Ph.D. student Kenny McMahon used the e-tongue to re-run the wines we just tasted.

McMahon points out the instrument doesn’t actually look like a tongue. The main feature is a robot arm that dips a sensor head into 1-ounce glasses lined up in a carousel. And the device does not respond, 'Hmmm... tasty!'"

"No, it doesn't give human quality aspects or human sounds,” McMahon said.

"There's a sensor for sweet, for salty, sour, bitter, and umami - that meaty, brothy taste,” Ross explained. “There's also a sensor for metallic and for spicy."

Ross bought the electronic tongue from the French instrument maker Alpha MOS.

"We're one of the early academic institutions to purchase one and kind of get in on the ground floor with seeing how it works,” she said.

Better than humans?

The electronic tongue doesn't gag or tire. The instrument is proving useful to winnow fields of samples and eliminate subjectivity. Its data feeds into research papers and presentations. In this case, the wine industry gets information on how their production tweaks affect the flavor and bubbles -- and what consumers notice and value.

But can the machine replace the humans at some point?

"No, no,” Ross said. “The complexity of our perception can't be replicated by an instrument."

Some of my fellow human panelists at the wine tasting agree. Alexandria Wyandt and Victoria Minette are both food science majors.

"I don't think it will totally take over,” Wyandt opined. “I think it will help and advance a lot of things that people can't and take out the human error."

"There's a lot about what consumers 'like' that the tongue can't give you,” Minette added. “So even if the tongue says it has a perfect taste profile, if the consumers don't have that in their mind as what is ideal, it’s not going to be able to tell you what is a good product."

WSU's food scientists found a high degree of correlation between the human panelists and machine results when they previously analyzed sweeteners, apple ciders, red wine and beer. When people call something bitter, so does the machine.

The electronic tongue is finicky though. Ross said it doesn't like solid food.

"It has to be in liquid form,” she said. “The sensors are very sensitive. We have to make sure there are no fat particles or no big particles. We have to filter everything.”

Commercial purposes

Manufacturer Alpha MOS said the pharmaceutical and beverage industries are other early adopters of the e-tongue. Alpha MOS Americas General Manager Andrew Cowell said it helps the pharmaceutical industry minimize human or animal taste testing of investigational drugs where the object is to make bitter medicines more palatable.

"Coffee and tea producers use it for quality control and to achieve batch-to-batch consistency," he added.

Cowell said other buyers of the expensive instrument include soft drink companies to monitor metallic tastes and sweetness, and beer makers to measure bitterness.

The electronic tongue has been on the market for more than three years. Alpha MOS ships about a dozen to the USA each year.

The electronic tongue works by applying a small electric current in the liquid sample. The device measures voltage differences which can reveal which molecules are present. Software analyzes and translates the identified compounds into the quantifiable components of taste.

Intelligent Sensor Technology, Inc. (Insent) of Japan also makes an e-tongue. On its website, the manufacturer said it began selling overseas in 2006. It said it has sold more than 100 to laboratories around the world.

Research teams from the University of Massachusetts-Lowell, at several different universities in Spain and at institutes in India are now working on miniaturizing e-tongues to make the technology portable and cheaper.