Acidity and Coffee: Fact vs. Fallacy

acids contribute more to sweet and sour tastes than to bitterness or upset stomachs

I’ve been serving up coffee in some way or form for years now. I consistently hear customers comment on coffee and its acidity.   Many coffee drinkers I’ve encountered have related stomach upsets, or “gut rot” they attribute to the acidity in coffee. Others relate it to a bitter taste or metallic bite.

A recent posting on the website Coffeechemistry.com clears up some of these misperceptions:
“Some people aren’t able to drink coffee because it bothers their stomach, but is it really the acid? In terms of the pH profile (a measure of acidity), coffee rates as low-acid, coming in at 4.5 – 6.0, depending on the coffee (A pH of 7.0 is neutral). Most sodas, diet sodas, orange juice and lemonade are significantly more acidic, at 2.0 – 3.0 pH.”

It goes further to say, “Acidity in coffee is not related to its pH level, and is actually considered to be a desirable quality. Acidity refers to the flavor profile, similar to the sensations you experience when drinking wine: the tartness, brightness, zing or various regional influences in the bean, that hit both your tongue and your palate when you take a sip.”

I was curious about how this relates directly to the gut rot problem. So I turned to Joseph Rivera, founder of CoffeeChemistry.com and coffee science guru. Here’s what he had to say about coffee’s acidity:
“The effects of pH on coffee are quite significant – typically the lower the pH (i.e., higher acidity) the greater the ability for volatile compounds to escape the cup and enter our nose – a good thing. Though there are some minor exceptions to this.

Stomach= 2-3pH Coffee= 4-6pH

Another common misconception is that acids are bitter, and that is incorrect. At least in coffee, which is made up of over 20 carboxylic acids – citric, malic, lactic, acetic, etc – all these acids are “sour/tart” – a characteristic due to the presence of H+ ions in solution. Bitterness, which they are confused with, is typically caused by amines – i.e., caffeine, nicotine, etc – and products formed during the roasting process.

As far as the stomach is concerned – we commonly see   a pH 3 range in most people. If so, this would make the “acidity” in our stomachs 32-1,000 x more potent than coffee with a pH of 4.5-6.0. When people talk about coffee upset stomach, its not due to coffee’s acidity (since it’s much lower than what is already there) but due to other effects and compounds found in coffee.”

Acidity is a pleasing characteristic of coffee. Think of the phosphoric acid added to sodas or citric acid in sweets and citrus, or malic acid found in all things apple. Perhaps high caffeine upsets the stomach, or maybe the 18-22% of solubles extracted from the ground coffee sit a bit heavy in the stomach of some. If so, you might want to drink darker roasts and brew coffee a bit weaker without losing too much flavor to hit a more drinkable sweet spot.

On the other hand, if it’s bitterness you shy away from, medium to lighter roasts tend to have bright, sparkling notes. Typically East African and Central American coffees will set you straight.  Truly great coffees marry the entire palate with a balance of sweet , sour and bitter notes that are often reminiscent of some our favorite taste associations: citrus and berries, stone fruits, chocolates, vanillas, caramels and sugars, malts, nuts and sweet vegetables.   A huge factor in creating that balance is the activity and character of the coffee’s acidity.  Both a mild and bright acidity can move the tasting experience along any number of paths.

Hopefully that clears up some confusion about coffee and acidity and gives you and coffee drinkers in your presence something to consider as you linger over your next cup.

Cheers- Ryan