What factors impact coffee’s acidity?
While there are several factors that can impact the coffee acidity level, three, in particular, stand out: The coffee’s roasting level, the bean type, and its extraction method.
The roasting process plays a vital role in the final acidity level of your coffee. During roasting, chemical reactions occur that can heighten or dull acidity. The general rule of thumb is: the darker the roast, the lower its acidity. The types of coffee roasts are as follows:
● Light roast – Lightly roasted coffee tends to have higher acidity. Since the beans are roasted for a shorter period at lower temperatures (around 356–401°F), they retain more of their original characteristics, including acidity. This acidity is what gives light roasts their bright, vibrant, and complex flavor notes.
● Medium roast – With medium roasts, the acidity is more balanced. Roasted to temperatures between 410–428°F, medium roasts strike a balance between preserving the beans' original acidity and introducing new flavors from the roasting process. This balanced profile makes medium roasts popular among casual coffee drinkers.
● Dark roast – Pushed to temperatures beyond 464°F, a dark roast has the least acidity of all. The dominant flavor notes in these roasts come from the roasting process, resulting in a sweeter, full-bodied cup with an intense and robust flavor profile.
Type of bean
Various types of coffee beans will also largely influence the level of acidity in your morning brew. That’s because some coffee beans themselves contain more acid than others.
● Arabica beans – Tend to be more complex, acidic, and flavorful than Robusta beans
● Robusta beans – Less complex, have less sugar, and contain twice as much caffeine as Arabica beans, resulting in a less acidic brew
Even after you have selected a bean and designated a roasting level, the acidity of your coffee can be further impacted by the method of extraction—or how the water is passed through the coffee grounds.
While no two brews are exactly alike, here’s a general ranking from least acidic to most acidic extraction methods:
● Cold brew
● French press
● Drip or pour over