App to Reveal if Your Beer is Fresh or Stale

In this scorching heat, chilled beer is what comes to your rescue but what if it has gone stale, threatening to spoil your party? No worries as now there is a smartphone app that can tell you if your beer is fresh to be gulped down tonight.

Chemists from the Complutense University of Madrid have developed a method that allows brewers to measure the freshness of beer by using a polymer sensor that changes colour upon detecting furfural - a compound that appears when this beverage ages and gives it a stale flavour.

The sensor can be controlled from a smartphone app.

Depending on the beer type and its storage conditions, its flavour may be altered as a result of changes in the chemical composition produced during beer that, unlike what occurs in wines, has a negative effect on the quality of the flavour.

Now, the researchers Elena Benito-Pena and Maria Cruz Moreno-Bondi developed a simple, low-cost method capable of measuring whether or not beer has gone stale.

Until now, brewers have measured furfural and other freshness indicators using methods based on chromatography techniques.

"But these methods involve the use of expensive equipment and sample preparation is very time-consuming," said Benito-Pena.

The new method consists of sensor discs that detect the presence of furfural in beer.

These sensors, made from a polymer similar to the one used to manufacture contact lenses, have been designed to change colour (from yellow to pink) when they come into contact with a beer containing furfural.

"We have incorporated a 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 chemists explained.

"The intensity of the colour increases as the concentration of furfural in the beer rises and, thus, as more time passes since the beer was produced," they added in a paper published in the journal Analytical Chemistry.

The team has also created a mobile app for Android smartphones that, by taking a picture of the sensor disc, allows for the identification of the amount of furfural present in the beer.

With this data, the degree of freshness can be determined.

The app is available as open source and any programmer can utilise and modify it to be used on other platforms.

It will also be available for Apple IOS devices soon.