Analysis of 467 beers reveals tens of thousands of unique molecules

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Germans have taken their love of beer to the next level with a new detailed study of the unique molecules in ales and lagers from around the world.

Scientists in Munich, in the beer-loving state of Bavaria, used advanced mass spectrometry techniques on 467 popular beers from Europe, the US and more.  

Around 80 per cent of the ‘tens of thousands’ of molecules they discovered aren’t yet described in chemical databases, they reveal. 

Their analysis takes only 10 minutes to detect thousands of metabolites per beer, making it a powerful new method for quality control, they claim.

Scientists in Germany used mass spectrometry to quantify the chemical complexity in beer from around the world. From left, a stout, a red ale, a pale ale and a lager (stock image)

Scientists in Germany used mass spectrometry to quantify the chemical complexity in beer from around the world. From left, a stout, a red ale, a pale ale and a lager (stock image)

WHAT IS MASS SPECTROMETRY? 

Mass spectrometry (MS) is an analytical detection technique used to determine information about individual chemical molecules.

MS is based on ionisation and fragmentation of molecules in the gas phase.

Since molecules fragment in a unique manner, the resulting ion fragmentation pattern can be used to obtain structural information for a given molecule.

In forensic science, MS has become the technique of choice for the definitive identification of a wide variety of evidence. 

‘Beer is an example of enormous chemical complexity,’ said study author Professor Philippe Schmitt-Kopplin at the Technical University of Munich. 

‘Thanks to recent improvements in in analytical chemistry, comparable in power to the ongoing revolution in the technology of video displays with ever-increasing resolution, we can reveal this complexity in unprecedented detail.’

For the analysis, published in Frontiers in Chemistry, the researchers used 467 beer types, which had been brewed in the US, Latin America, Europe, Africa and east Asia, including lagers, craft and abbey beers, top-fermented beers and Belgian gueuzes. 

They used two powerful methods – direct infusion Fourier transform ion cyclotron resonance mass spectrometry (DI-FTICR MS) and ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-ToF-MS). 

DI-FTICR-MS can predict chemical formulas for the metabolite ions in beers, while UPLC-ToF-MS uses chromatography to predict their exact molecular structure.  

They found about 7,700 ions with unique masses and formulas, including lipids, peptides, nucleotides, phenolics, organic acids, phosphates and carbohydrates – of which around 80 per cent aren’t yet described in chemical databases.

Because each formula may in some cases cover up to 25 different molecular structures, this translates into tens of thousands of unique metabolites.

‘Here we reveal an enormous chemical diversity across beers, with tens of thousands of unique molecules,’ said first author Stefan Pieczonka, a PhD student at the Technical University of Munich.

‘We show that this diversity originates in the variety of raw materials, processing, and fermentation.’

The beers’ molecular complexity is amplified by the so-called ‘Maillard reaction’ between amino acids and sugars.

Stamp issued in 1983 celebrating the history of the Reinheitsgebot, commemorating its 450th anniversary. While no longer actual law, the Reinheitsgebot is still regarded as an important tradition and for many brewers a guideline on how German beer ought to be made

Stamp issued in 1983 celebrating the history of the Reinheitsgebot, commemorating its 450th anniversary. While no longer actual law, the Reinheitsgebot is still regarded as an important tradition and for many brewers a guideline on how German beer ought to be made

ALE OR LAGER?  

Beers are generally made out of four ingredients – grain, hops, water and yeast.  

All beers can be classified as an ale or a lager.

Ales use top-fermenting yeasts – yeasts with cells that are carried to the top of the fermenting liquid. 

Lagers use bottom-fermenting yeasts – yeast cells collect at the bottom of the fermenting liquid.

Bottom-fermenting yeasts work effectively at lower temperatures than top-fermenting yeasts.  

The Maillard reaction is what gives bread, steaks and toasted marshmallow their toasty or sweet malty flavor. 

It’s also responsible for turning sweetened condensed milk into Dulce de leche (the delicious South American spread) after just three hours in boiled water. 

‘This complex reaction network is an exciting focus of our research, given its importance for food quality, flavor, and also the development of novel bioactive molecules of interest for health, said Pieczonka.

Their state-of-the-art mass spectrometry method could be used for quality control in the food industry – such as identifying any dubious ingredients in beer that violate its Vorläufiges Biergesetz (Provisional Beer Law) of 1993. 

Vorläufiges Biergesetz was a revision of Germany’s hallowed, 500-year-old Purity Law, known as the Reinheitsgebot. 

The decree, originally imposed by the southern state of Bavaria on April 23, 1516, stated ‘no ingredients other than barley, hops and water are to be used’ in making beer – although Germans later realised the importance of beer’s fourth key ingredient, yeast. 

Nowadays, beverages that are sold as beer are open to a large number of brewing types and raw materials, the researchers point out, which could lead to adulterations.  

‘Today it’s easy to trace tiny variations in chemistry throughout the food production process, to safeguard quality or to detect hidden adulterations,’ said Schmitt-Kopplin.  

The German experts say advanced mass spectrometry techniques can identify ingredients in beer that shouldn't be there

The German experts say advanced mass spectrometry techniques can identify ingredients in beer that shouldn’t be there

Beer needs to include four key ingredients to be technically classified as such – water, yeast, hops and a certain type of grain. 

Beers were either brewed from barley as the grain, or barley with the addition of either wheat, rice, and corn. 

Wheat beers tend to be found throughout Germany, while rice beers are popular throughout Japan but are fairly rare in British supermarkets. 

For centuries, brewers have been adding extras to their four ingredients like fruit, vegetables, chocolate or even oysters for extra flavour. 

One Illinois-based brewer even added the ingredients of a pizza – tomato, oregano, basil and garlic – for its Mamma Mia! Pizza Beer.   

SCIENTISTS PROVIDE THE BEST ESTIMATES YET OF HOW MANY BUBBLES ARE IN A PINT OF LAGER 

There’s up to 1.5 million bubbles in a glass of gently-poured lager, a 2021 study reveals. 

French scientists say their estimate is for a 250 ml (nearly a half-pint) glass of commercial lager with a 5 per cent alcohol content. 

The experts calculated the amount of carbon dioxide (CO2) bubbles in lager – which accounts for its creamy white froth –  and imperfections in a glass that make the CO2 bubbles form. 

Lager still doesn’t fizz up quite as much as champagne, however – research shows there are more bubbles in the sparkling wine than lager when comparing the same volume of both drinks. 

For their study, the researchers first measured the amount of CO2 dissolved in Heineken, the commercial lager, just after pouring it into a glass. 

Using this CO2 value and a standard tasting temperature of 42°F (6°C), they calculated that dissolved gas would spontaneously aggregate to form streams of bubbles wherever crevices and cavities in the glass were more than 1.4 micrometre in width.

Read more: Scientists calculate the amount of bubbles in a glass of lager  

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