Beer filtration could add arsenic


beer

Why is there arsenic in your beer? © Shutterstock

The Germans take the purity of their beer seriously. Back in the 16th century the Reinheitsgebot, or beer purity law, specified that the only ingredients that could be used in beer were water, barley and hops. Once it was realised that yeast was involved in the brewing process that was allowed as well. Today, the Provisional German Beer Law allows slightly different components but it certainly doesn't specify that arsenic can be added to the beer. Mehmet Coelhan of the Weihenstephan research centre at the Technical University of Munich, Germany, however, has found that that is exactly what brewers might unwittingly be doing. He suggests that the material used to filter beers might add arsenic at the same time as it removes yeast.

A 2008 paper found high levels of arsenic in Italian beer - up to two and a half times the legal limit of 10μg/l in the US and Europe - but they didn't investigate where that might have come from, explains Coelhan. The Weihenstephan research centre, which focuses on beer related research and carries out a lot of analysis for the brewing industry, analysed nearly 360 samples of beer for heavy metals. They found that some had levels over that 10μg/l threshold. And, added Coelhan, 'there is almost always arsenic in beer'.

The puzzle was that when the team analysed the water, malt and hops used, they couldn't make the amount of arsenic in those ingredients add up to the level of arsenic in the beers. The answer, says Coelhan at the 245th ACS National Meeting & Exposition in New Orleans, US, lies in the material used to filter the beers after fermentation, kieselguhr.

Coelhan's team found that there could be large amounts of what Coelhan calls 'extractable arsenic' in the substance, which is a diatomaceous rock made from fossilised algae. Kieselguhr is mined in various countries, mainly the US, France and China, and once powdered is used by brewers to remove yeast and sediment from beer. Some of the kieselguhr that Coelhan analysed released arsenic at up to 12μg/l, but Coelhan adds that there are no regulations on acceptable levels of arsenic in beer.

Janet Hock from the Centre for Urban Health at Indiana University, US, who is discussing arsenic exposure at the meeting, explains that at the moment it isn't clear what level of arsenic is acceptable. 'The concern is how much of a health risk is added via arsenic coming in through food (or beer) - does it push it to a higher risk level than we can accept?' she adds. The other variable is of course that we don't drink beer constantly in the same way we're always consuming water. That says Hock, further complicates trying to quantify the health risks. 'Is the gap between arsenic "loading" long enough to allow recovery and reversal of whatever pathways have been activated?' she says. 'I find very little literature on the resilience of humans to arsenic, let alone intermittent arsenic intake.'

However, as well as switching to a different filtration method, explains Coelhan, brewers could switch to using kieselguhr with low levels of arsenic or to treat the material to remove the arsenic before use. If beer can remove arsenic so could other solvents, perhaps even water. For this research the team in Munich only received kieselguhr samples from breweries, not from keiselguhr suppliers. More analysis is needed to quantify the different commercially available sources.


Related Content

Chemistry World podcast - May 2013

2 May 2013 Podcast | Monthly

news image

Robert Lovitt tells us about algae biotechnology, Patrick Holland discusses nitrogen fixing chemistry and the team cover the ...

Trouble brewing

31 July 2008 Premium contentFeature

news image

Chemical reactions during storage can destroy a beer's flavour. Henry Nicholls finds out how brewers are striving to stabilis...

Most Read

First experimental evidence of a boron fullerene

14 July 2014 Research

news image

Distorted 40-boron atom fullerene detected mixed with quasiplanar isomer

Linguistic statistics enable synthetic prophetics

17 July 2014 Research

news image

A metric more commonly used by search engines to analyse language can now power organic chemistry retrosyntheses

Most Commented

Royal Society of Chemistry's flagship journal now free to access

16 July 2014 News and Analysis

news image

Chemical Science will follow gold open access model from January 2015 and waive author fees for two years

Science minister replaced in UK cabinet reshuffle

15 July 2014 News and Analysis

news image

Greg Clark replaces David Willetts as minister for science and universities