Scientist Babineh Mahmoodi from the École Polytechnique Fédérale de Lausanne claims in an article for Science News that coffee is naturally alkaline. She explains that acidity is associated with an increase in protonation of acids by proteins resulting in strong acids. Proteins are found at both ends of the molecule, which is a key reason coffee actually tastes less acidic.
"So let's get to the bottom of this," writes Mahmoodi. "Perhaps the caffeine that so many claims drives coffee's acidity has little to do with the acidity itself." Instead, she believes that the acid is from substances in the roasted coffee.
Interestingly, when coffee beans are roasted for less than 40 seconds they result in coffee that has significantly lower levels of acidity. By roasting for less time the concentration of acid declines (although it is not statistically significantly lower).
So when looking at the actual acidity of coffee one can see that even in poorly brewed coffee, it is unlikely that any portion of coffee would be particularly acidic.
What does it all mean?What do you think about the differing opinions on coffee's acidity? Have you ever noticed that coffee has a different, potentially unpleasant acidity when it is roasted or ground differently?
ABSTRACT Coffee is naturally alkaline and the pH of the coffee has more to do with the acid content of the coffee rather than the acidity of the coffee. Coffee itself is about 50% acid. Coffee extracts are less acidic than coffee brewed from freshly roasted coffee beans. Coffee is much less acidic than tea and significantly less acidic than lemon juice. Although coffee contains some organic acids and sugars, there are many natural substances that remove or reduce these acids. These substances and treatments have given coffee its overall neutral pH of about 4.