Not all people know that coffee is sour. Sometimes customers ask me, “Why is this coffee sour? Is it spoiled?” So, I thought that I have to write about it. This question is often asked by people who used to drink either robusta or the blends where it prevails.
Sour coffee and acidic coffee are completely different notions. The acidity of coffee, or that slightly sour note, is perhaps one of the most controversial characteristics of the coffee taste, but it is one of its constituents. If the coffee is sour, it means that there was a mistake at some stage of the brewing process.
Coffee beans grow like berries on coffee trees in a tropical climate. A little sourness is a standard characteristic of tropical fruits. Coffee is no exception, and almost all arabica beans taste sour. The higher the beans grow, the higher the intensity of sourness is. Acidity is highly-rated in coffee around the world, so high-altitude coffee is considered one of the best. For the same reason, washed arabica is of greater value around the world than natural arabica since this processing method contributes to the intensification of acidity.
As a rule, coffee gourmets come across this coffee type while searching for a new, interesting, and unusual taste. In fact, sourness is responsible for the variety of coffee flavors. We can tell one coffee blend from another by the type of acidity. There are three types of acidity:
- citrus (lemon, orange; for example, Costa Rica);
- floral (somewhat reminiscent of Isabella grape; for example, Ethiopia Yirgacheffe, Yemen);
- cocoa (a nutty flavor; for example, Nicaragua).
What about robusta? There is no acidity in robusta. Therefore, if you don’t like sour flavors, you can choose this type of coffee.
Which are the parameters that determine how acidic the coffee will be?
- place of growth. The higher it grows, the more organic acids it contains because the ripening time increases;
- degree of roast. The coffee with a dark roasting degree tastes less acidic;
- processing method. Washed coffee is always more acidic and has a clean taste profile;
- brewing method. Pour-over coffee has pure acidity; the acidity in espresso is concentrated; the coffee brewed in a cezve, a siphon coffee maker, and a Moka pot loses acidity;
- brewing time. With the shorter brewing time, the acidity is more pronounced.
All these features are characteristic of traditional coffee acidity. However, coffee can taste sour because it wasn’t properly extracted or, on the contrary, it was over-extracted. In fact, you won’t confuse this coffee because this sourness will be accompanied by bitterness, low sweetness, and a short aftertaste.
Don’t be scared if your coffee tastes acidic. If you’re switching from robusta to arabica, the first impression will be unusual, and at first, you’ll have to get used to it. After you get accustomed to it, you’ll never return to a plain bitter taste.