German researchers have solved the mystery of why some native beers have higher arsenic levels than those present in water tested before brewing – use of diatomaceous earth as a clarifier.
Diatomaceous earth is the fossilized remains of diatoms, hard-shelled algae with silca cell walls that lived millions of years ago, and is widely used to filter beer and wine.
Mehmet Coelhan from the Technische Universitat in a poster presentation to the 245th National Meeting & Exposition of the American Chemical Society on April 7, that the discovery could be of importance for breweries and other food processors.
140 German beer samples tested
Alternatives to diatomaceuous earth – which has GRAS status in the US – were available, he explained, while simple measures like washing it with water prior to use can remove arsenic.
Testing 140 samples of beer sold in Germany, Coelhan and his team checked levels of heavy metals including arsenic and lead, as well as pesticides, natural toxins that can contaminate brewing grain, and other products.
The World Health Organization (WHO) limit for arsenic in drinking water is 10 micrograms/liter but some beers tested exceeded these levels.
Excess drinking more harmful
After analysing all materials – including malt and hops used during brewing – for arsenic, Coelhan said the team found that the arsenic was released into beer via kieselguhr (diatomaceous earth) used to remove yeast, hops and other particles and give the beer a clear appearance.
Tests revealed that some kieselguhr samples release arsenic, although the resulting arsenic levels in beer were only slightly elevated, and it is not likely that people would get sick from drinking beers made using this filtration method.
“The arsenic is still at low levels — the risk of alcohol poisoning is a far more realistic concern, as stated in previous studies on the topic,” Coelhan said.
Beers brewed in at least six other countries had higher arsenic amounts than German beers, Coelhan said, citing but not naming a report published four years ago.