Coffee is slightly acidic with a pH ranging from 4 to 5, with 4 being the most acidic. However, its acidity depends on various factors.
Why is coffee acidic? Here are five reasons.
- As the coffee cherry develops on the tree – citric and malic acids are formed, giving it a tart or acidic taste like that of a lemon or a green apple.
- Coffee plants that grow in high altitude and shady areas are more acidic than those grown in other conditions; the former has cherries that are packed with higher levels of organic acids, caffeine, and sugars.
- The level of chlorogenic acid, sucrose, fructose, and other organic acids depend on the plant species. For example, Robusta coffee has twice as many chlorogenic acids than other beans.
- Coffee processing affects the level of acidity of coffee beans. Naturally pulped coffee beans are less acidic than washed ones. Washing takes away fructose, sucrose and other content from coffee, making it more acidic.
- Roasting breaks down organic acids, resulting to a metallic taste in your brew.
There are also other reasons why your coffee could taste more ‘acidic’; like letting it sit for a few hours whether on a hot plate or anywhere else because of the chemical reactions that increase its level of acidity.
So, is my cup of coffee acidic?
Chemically speaking, coffee is acidic because it contains acidic properties such as chlorogenic acid, tannins, and polyphenols. The caffeine in coffee also stimulates the release of more stomach acid, causing stomach irritation to some people. However, that’s different from describing your coffee as an acid or a base, because when compared to some the pH values of common beverages from the FDA, coffee is tolerable.
For example, Kenyan coffee has a PH of 4.3; while blueberry lemonade has 2.9 PH, Grapefruit Juice has 3.6 PH and apple juice has a PH of 3.8. In fact, coffee is less acidic than soda and beer!
If you’re not sure whether your coffee is acidic or not, you can dip litmus paper into your coffee. When it turns red, your coffee is acidic. Those who want to get an accurate scale can squirt a few drops of coffee into a container. Just add a few drops of the indicator and check whether the coffee is acidic or alkaline based on the indicators PH scale.
Anthony is a professional barista in the city of Chicago. He has written for many online publications on various topics related to coffee.