Coffee Myths: Light Roasts & Acidity
It is a common misconception that light roasted coffee is more acidic than darker roasted coffee. All coffee has a pH of roughly 5, regardless of roast. There are slight variations in the chemical composition of various origins and varietals, but the impact on your daily cup is negligible.
While the overall pH is the same, there are different types of acids in different roasts of coffee. Acids chemically break down when exposed to heat, so light roasted coffee has a different acid composition than its dark roasted counterpart due to the differences in roasting time and temperature.
Our taste buds can register some acids more easily than others. This phenomenon is called “perceived acidity”: variations in how tart something seems, despite a constant pH. The acids present in light roast are more easily detected by our palates. Citric acid for instance, the primary acid found in lemons, is often a characteristic of light roast coffee, and is likely why light roasts get such a tart reputation. So, while it is false that light roast is more acidic than darker roasts, it often has a higher “perceived acidity” and generally makes for a brighter, fruitier cup.