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Study: Common Coffee Toxicants Cannot Be Simultaneously Reduced in Roasting

coffee roaster

Chemical compounds acrylamide and furan occur naturally during the coffee roasting process.

New research suggests that simultaneously mitigating the presence of two common food-born toxicants in roasted coffee is impossible, since one increases with longer, darker roasts, while the other decreases.

Conducted by researchers at the food chemistry institute at Germany’s Technical University of Braunschweig (Technische Universität Braunschweig), the study found that the chemical compound acrylamide formed quickly during the browning phase, but decreased as roasts went longer and darker. Meanwhile, furan/methylfurans concentrations were lowest with the lightest roasts and increased as roasts darkened.

Both chemical types have been a popular subject among food chemistry researchers due to their presence in popular foods, as well as their classifications among public health agencies.

The International Agency for Research on Cancer (IARC) has classified acrylamide — which occurs naturally during most baking, roasting or otherwise browning of foods — as a “probably human carcinogen” while the United States EPA has classified it as “likely to be carcinogenic to humans.” Furan also falls into the IARC classification of “probably carcinogenic.”

roasted coffee

The new German study comes with the caveat that coffee is also loaded with antioxidants that are believed to be beneficial to human health. Multiple recent studies have suggested regular coffee consumption can help fend off death from all causes, including cancers.

The new study sought to determine whether acrylamide and furan levels in roasted coffee could be reduced by altering roasting times, temperatures and profiles. The study also explored results from different mechanical roaster types (drum or hot air), as well as coffee types (a Vietnamese Robusta and a Brazilian natural Arabica).

“The overall conclusion from the data in this study is the confirmation that a simultaneous mitigation of acrylamide and furan/methyl furans by varying the roasting parameters is not possible,” the open-access study states. “This proved to be true for both the analyzed Brazil Arabica and Vietnam Robusta samples.”

The researchers further noted that strategies to mitigate the presence of food-born toxicants might negatively affect properties desired by consumers.

Additionally, the researchers noted that the presence of acrylamide and furan in consumable coffee is significantly affected by brewing and preparation methods, for which the study did not account. This study focused solely on the impacts of roasting.

“For lower content of acrylamide, darker and longer roasts can be recommended,” the authors wrote. “On the other hand, the characteristics of the coffee will be completely changed and most consumers will not accept that due to lower acrylamide content resulting in only dark roasted (espresso type) coffees on the market. Moreover, furans will be higher in darker roasts.”

The complete study was published in the journal Plant Beverage Research.

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1 Comment


Specific information on what these two chemicals DO in the human body, and what harms result, and, most important, some idea of threshhold “dose” of the two chemicals.
Further, are there other compounds in coffee that mitigate the unwanted effects of these two chemicals, and to what extent.

Some usable information on the practical dangers from these two chemicals is in order. Until then this is mostly fact for its own sake. Not practically usable.

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