Effect of fine grinding of coffee grinder on acidity and bitterness of coffee

The fine grinding of a coffee grinder has a significant impact on the acidity and bitterness of coffee, which is mainly related to the extraction rate, release of chemical components and taste experience brought about by fine grinding.
Finely ground coffee powder has a large surface area and can quickly contact more coffee particles when water flows through it. This high surface area allows the water to more quickly extract dissolved substances in the coffee, especially acids. Fine grinding often results in a significant boost in acidity when brewing, especially when using premium coffee beans, which can reveal bright fruit acids and refreshing flavors. This is an advantage for those who like their coffee sour, but for some drinkers, too much acidity may cause an unbalanced taste.
Another important effect of fine grinding is the increase in bitterness. With fine grinds, coffee grounds tend to be over-extracted, especially if steeped for a long time or brewed incorrectly. When coffee powder is soaked too much, in addition to sourness, bitter components (such as chlorogenic acid and caffeine, etc.) are also released. These bitter substances tend to cover the original flavor of coffee, resulting in a single taste and lack of layering.
In order to balance the acidity and bitterness brought by fine grinding, baristas often adjust the brewing method and time according to the specific brewing method. For example, when using a fine grind for espresso, short brew times and high pressure can quickly extract rich flavors while controlling the balance of acidity and bitterness. However, if finely ground and used for French press, the bitterness will tend to increase due to the longer steeping time. The effect of fine grinding on the acidity and bitterness of coffee is complex and subtle. While it can enhance the acidity of coffee and reveal richer flavor layers, it can also cause over-extraction and increased bitterness. Therefore, when choosing a fine grind, it is critical to master the appropriate brewing time and method.