What is a common mistake when brewing coffee?

Using the incorrect grind size is a common mistake when brewing coffee because it can significantly impact the extraction process and, subsequently, the flavor of the coffee. Each brewing method has an optimal grind size that corresponds to the time the coffee is in contact with water. For instance, a coarse grind is typically suitable for methods like French press, which involves longer brewing times, while a fine grind is ideal for espresso, requiring a quick extraction. If the grind size is not appropriate for the brewing method chosen, it can lead to under-extraction or over-extraction, resulting in a cup that lacks balance and complexity. Proper grind size ensures that the flavors are adequately extracted and contributes to achieving the desired taste profile of the final brew.