Beer is a commonly consumed beverage worldwide, and beer connoisseurs will tell you that a beer’s flavor is important to its quality rating. Sometimes beer flavors can be altered if they are poorly stored, and unlike wine, changes in chemical composition do not improve the beverage over time. So how can you tell if you are about to indulge in stale beer? Chemists from the Complutense University of Madrid have got you covered with an application and some sensors that measure the freshness of beer.
The new method uses a polymer sensor that changes color when it detects furfural, a compound that appears when beer ages and gives it a stale flavor. The sensor can be controlled via smartphone application, which was also created by the team.
The team, led by Elena Benito-Peña and María Cruz Moreno-Bondi, created a simple, low-cost method that measures whether beer has gone stale by using a sensor and a smartphone application.
Until now brewers have measured furfural and other freshness indicators using methods that employ chromatography techniques.
"But these methods involve the use of expensive equipment and sample preparation is very time consuming,” said Benito-Peña.
Instead, this system uses sensor discs, composed of a polymer similar to the one in contact lenses, to detect the presence of furfural in beer. The sensors change color, from yellow to pink, when they come into contact with a beer containing furfural.
"We have incorporated an aniline derivative into the sensor material, which reacts with the furfural and produces a pink cyanine derivative that allows us to identify the presence of the marker in the sample. The intensity of the color increases as the concentration of furfural in the beer rises and, thus, as more time passes since the beer was produced," said Benito-Peña.
To accompany the sensors, the team developed a mobile application for Android smartphones that takes a picture of the sensor disc in order to identify how much furfural is present in the beer. This data indicates the degree of freshness.
The application is currently available open source, and the team plans to make it available for iOS in the near future.
The idea of the sensor and application came from a meeting with the Mahou-San Miguel brewing company, in which Benito-Peña was informed of the technical difficulties the company was having when it came to detecting furfural directly at the production facilities.
"The measurements have been taken using samples sent directly from the brewing company with different production dates and distinct degrees of aging. These same samples were also sent to a laboratory where they were analyzed using gas chromatography coupled with mass spectrometry. The results we obtained were completely comparable," said Moreno-Bondi.
While the technology has been initially designed to cater to brewing companies, the researchers emphasize that it can be used on many other food products as well, such as honey, milk and coffee.
UCM collaborated with the Mahou-San Miguel brewing company to help further its research.