One Large Coffee, Hold the Dirt - OZY | A Modern Media Company

One Large Coffee, Hold the Dirt

One Large Coffee, Hold the Dirt

By Anne Miller


Dirt. In your coffee. Yech. 

By Anne Miller

Gross alert: Those grounds you shoveled into the filter this morning may have included more than coffee — dirt, twigs, parchment, husks and other “impurities” might also be in there.

Yuck. Why? Blame a pending coffee shortage trigged by climate change. For example, Brazil typically exports 55 million bags of coffee annually. This year, predictions put production around 45 million, thanks to a drought.


If you’re a coffee supplier, trying to boost the amount in each tin of grinds you sell so business doesn’t dry up along with the plants — well, you get the idea.

A new test, developed by a team at the State University of Londrina in Brazil, can detect impurities in coffee grounds. Coffee companies say no grind may be perfectly clean and some impurities are likely — nature isn’t spotless. But the scientists say they’ve found enough impurities in some blends to believe that there’s something more nefarious going on.

Suzana Nixdorf, who led the study, explained the science behind the test via email: Coffee has a specific composition of sugars (carbohydrates), so it’s possible to test the carbohydrates in a sample ground coffee and then compare the results, mathematically, to the known carbs in good coffee. And to see where the grinds come up short. Because a lot of the mystery bonus compounds can look like coffee grinds, it’s almost impossible to tell the tiny granules apart in the can just by sight.

But this is an issue with ground coffee only. Coffee beans, roasted or otherwise, can’t hide impurities the same way.

Let’s be clear: Nixdorf didn’t call out any specific brands. And she’s not saying that every coffee company plays so fast and loose with your morning cuppa Joe.  

But she was very clear in her advice: If you want to make sure you’re really drinking coffee in the morning, and not a bit of Amazonian top soil too, buy roasted beans and grind them yourself. 


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