Nobody wants stale beer. Thanks to a group of chemist-scientists, there is now a smartphone app that can tell if your cold brew has gone stale.

A compound called furfural gives aged beer that dreaded stale taste. The chemist team created a polymer sensor that will change colors when it detects furfural in a batch of brew. They also developed a sensor-controlled smartphone app that can determine the level of furfural.

Prior to the study, brewers have been using chromatography techniques to measure if a batch of aged beer has gone stale. With no alternative techniques, the process of detecting furfural and other indicators of freshness can be expensive and time-consuming.

In the newly developed process, the team used polymer sensors that are comparable to the ones used in making contact lenses. These sensors are designed to turn from yellow to pink in the presence of furfural in a substance. The color intensifies depending on the concentration of the furfural detected.

Cheers To Fresh Beer

The smartphone app can analyze the photos of the sensor disc by identifying furfural content. Brewers can use this data to determine the beer's freshness level.

"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," said Elena Benito-Peña, one of the chemists who led the team from the Complutense University of Madrid.

The sensor-and-app development followed a meeting with Mahou-San Miguel, which has been experiencing technical difficulties in furfural detection directly at the company's production plants. Benito-Peña shared that the new system has produced "very satisfactory" results.

For the tests, the team used beer samples taken from the brewing plants. The samples differed in aging degrees as well as production dates.

The same samples were analyzed using the conventional processes of gas chromatography and mass spectrometry and the results were comparable with the ones produced by the sensor and app.

The open source smartphone app will soon become available via Apple iOS. As an open source app, other programmers can tweak and make it work on other platforms. This suggests that it can be used in wide-scale breweries.

The study is published in the Analytical Chemistry journal.

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