Electronic nose identifies beer quality

A team of researchers from the University of Melbourne have developed an “electronic nose” for craft brewers to determine beer quality, as the growing industry strives for greater quality control measures.

The “e-nose” is a small circuit board which is placed over a sample of beer which measures the gases emitted and uses machine learning to assess the quality of the beer.

It is the latest iteration of an ongoing project which started out using Lego prototypes to ensure a perfect pour and measure bubbles and carbon dioxide in beer, before the researchers, including Associate Professor Sigfredo Fuentes and PhD candidate Claudia Gonzalez Viejo, advanced the idea.

“We’ve been working on it for four years, we did it with Lego models [to start with],” Professor Fuentes told Brews News.

“The main objective was to pour the same amount every time, if you do it manually there are different velocities and it’s all over the place.

“So with the robotic pourer and a high-definition camera we can video the pouring, how the foam forms and dissipates, the colour of the beer, assess the size of bubbles and separate between small, medium and large.

“Then the e-nose measures temperature using infrared. We don’t put anything in contact with the beer, and there are nine gas sensors that analyse all the volatiles that are released in the pouring.”

The sensors in the “e-nose” are calibrated to measure these volatiles, namely gases like carbon dioxide, ethanol, methane, hydrogen, hydrogen sulfide, carbon monoxide, ammonia and benzene, all of which can affect beer quality and differ between fermentation styles.

“We have a really efficient intelligence model developed and a database of around 250 different brands not only from Australia, but around the world.

“Even small brewers can put their samples in, we acquire the data and we can position the beer among the brands and styles.

“We did some trials with La Sirène on the Lambic beers they had, and they were really happy, they were positioned with a few Lambic beers from Belgium.”

Gas chromatography instruments can analyse beer vapours, but this would require sending samples away to be analysed and can be costly according to the researchers, which is why a small portable device will allow practical application in the brewery.

It’s being launched at a critical time for the industry as brewers grow and look to maintain quality control throughout their core and limited release ranges, which have caused problems like product recalls in recent years.

Biometric indicators

The electronic nose has also been used by the researchers in conjunction with biometric indicators such as heart rate, body temperature, brainwaves and facial expressions to gather more information from consumers while tasting a product.

“Those physiological changes are an unconscious response so they are basically what we have imprinted throughout evolution, our relationship with food and beverage is ancient, since before language even,” explained Fuentes.

“Food appreciation is around 80 per cent unconscious, so the bitterness or sweetness for example is all conscious, but that is only 20 per cent of the information.

“So with the physiological changes we can tap into the unexplored parts.

“Sensory science after the Second World War has only based on conscious [responses] and we’re the first to put all this physiology and analysis and emotional response to beer.”

Fuentes said that the team had developed 25 parameters which are used in machine learning and artificial intelligence.

“Just with those parameters we can assess whether people will like it.

“We generate a model to assess whether they come from different fermentation types, like top, bottom or Lambic.

“It’s 96% accurate and we can also assess by different cultures whether someone will like the beer just with the pouring aspect, and different sensory aspects, like the bitterness they’re going to find.”

Bacterial infections

As brewers continue to strive for the new, exciting and experimental beers, quality control will rise even further to the fore.

That’s why the next step in the University of Melbourne research will be to explore and learn to be able to identify bacterial infections in beer.

“This semester we’re trying to target faults in wine and beer from different origins, whether that’s bacterial or chemical contaminants,” explained Fuentes.

“We contaminate the beer, so we know what it is and see how the electronic nose can compare those.

“People aren’t going to drink it, but we will calibrate the electronic nose against gas chromatography so we can target it to specific faults using machine learning.”

The researchers originally experimented with dogs’ sense of smell to determine faults in beer, but for obvious reasons moved to a more technology-focused approach.

“Dogs can sniff compounds in parts per trillion, if you train them they can even detect insects in a field.

“We have trained them to detect brettanomyces, which happens in the barrels of wineries.

“The electronic nose is going to be more efficient, dogs are efficient but you need to keep them focused because they get bored!”

Future research

“Our new project is assessing beer’s effect on happiness. There’s a compound called hordenine, an alkaloid that comes from barley grains [which has been shown to “significantly contribute to the mood-elevating effects of beer“] so it’s not just alcohol making you feel happy.

“We’re doing tests of alcoholic compared to non-alcoholic beers from the same brand, and you can see objectively if the beer is making you happy or it’s a mixture of compound and alcohol.”

In the meantime, to make the e-nose more accessible to brewers and commercially viable, the University of Melbourne researchers are looking at downsizing the sensor and integrating rechargeable batteries.

They say it will allow brewers greater flexibility, as the current version needs to be connected to power an a computer via USB.

“Small brewers can do it with just a pouring, we can get a lot of information from that.

“In Australia in general and Victoria in particular, there’s a bloom of craft beer breweries, we’re coming to a beer peak here in Victoria, people are willing to try new beers but in the long term they go back to their preference.

“If you don’t do analysis to maintain your competition and modify your product, you are condemned to fail.

“The commercialisation of the e-nose is to support small brewers and craft brewing, they can’t have a trained panel of people, it takes years to train them, so the only way they can assess quality of beer is the brewer or someone trained to do it.

“The brewer can say yes it’s fine, but in the market, for every new product you need to do a proper analysis of sensory and appreciation of consumers.

“To compete commercially you need to have strong and accurate technology,” Fuentes explained.

Any interested brewers can find out more about Professor Sigfredo Fuentes and the e-nose project on his University of Melbourne research profile.

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