New quick stale-beer tester could prove food freshness

It’s the worst of things for a seasoned beer drinker – chugging down a beer, only to find that it is stale. By then it’s too late. The tastebuds have been ruined and you might as well embrace an early night’s sleep.

But a solution is at hand: Chemists from the Complutense University of Madrid have found a cheap and quick way for people to measure how fresh their beer is.

Their solution uses a polymer sensor which changes colour when it detects furfural. This is a compound that pops up when beverages age to the point where they start going stale. The sensor can be dropped in a drink, where it changes colour from yellow to pink when it comes in contact with any beer that contains furfural.

Writing in the journal Analytical Chemistry, chemist Elena Benito-Peña said: “The intensity of the colour increases as the concentration of furfural in the beer rises as more time passes since the beer was produced.”

That reaction is sensitive enough that beer drinkers can still take a chance on only slightly stale drink – if they’re stuck in the desert and have no other option. The linked smartphone app then tells would-be drinkers how stale the beer is, depending on the intensity of the colour change.


Up until now, breweries have had to use a complicated and expensive process to check if their beverages had gone off. This has made it prohibitively expensive for bars and consumers to further check their drinks. Elena Benito-Peña said: “These methods involve the use of expensive equipment and sample preparation is very time consuming.”

The system has been tested at breweries, where its findings were measured against the results from the breweries’ own – much more expensive – checks. It was also tested against freshness tests at a laboratory.

Beer is just the start, according to the team’s research paper. “The global market for this product is huge. But it can also be used with other food products, such as honey, milk, coffee, etc.”

That application could be greatly beneficial in countries where a great deal of food is thrown away because it goes stale right after purchase. In South Africa, nine million tonnes of food are thrown away every year, according to the Institute of Waste Management.

Fixing a problem for beer drinkers could go a long way to fixing a great problem for all consumers.

Subscribe to the M&G

These are unprecedented times, and the role of media to tell and record the story of South Africa as it develops is more important than ever.

The Mail & Guardian is a proud news publisher with roots stretching back 35 years, and we’ve survived right from day one thanks to the support of readers who value fiercely independent journalism that is beholden to no-one. To help us continue for another 35 future years with the same proud values, please consider taking out a subscription.

Sipho Kings
Sipho Kings is the acting editor-in-chief of the Mail & Guardian

Related stories

Advertising

Subscribers only

Poachers in prisons tell their stories

Interviews with offenders provide insight into the structure of illegal wildlife trade networks

Covid-overflow hospital in ruins as SIU investigates

A high-level probe has begun into hundreds of millions of rand spent by the Gauteng health department to refurbish a hospital that is now seven months behind schedule – and lying empty

More top stories

The politics of the Zuma-Zondo showdown

Any move made by the Zondo commission head or by former president Jacob Zuma must be calculated, because one mistake from either side could lead to a political fallout

Museveni declared winner of disputed Uganda election

Security personnel out in force as longtime president wins sixth term and main challenger Bobi Wine alleges rigging.

Pay-TV inquiry probes the Multichoice monopoly

Africa’s largest subscription television operator says it is under threat amid the emerging popularity of global platforms like Netflix and Amazon Prime

​No apology or comfort as another Marikana mother dies without...

Nomawethu Ma’Bhengu Sompeta, whose funeral will be held this weekend, was unequivocal in calling out the government for its response to the Marikana massacre
Advertising

press releases

Loading latest Press Releases…