Why Use Freshly Ground Coffee? How to Brew and How Long It Lasts

Coffee Knowledge Exchange

For more coffee bean information, please follow Coffee Workshop (WeChat public account: cafe_style)

The Deterioration of Freshly Ground Coffee

When you smell the fragrance of freshly ground coffee powder, it indicates that it is already deteriorating, and the essence within the coffee is diminishing.

If the diameter of coffee particles is reduced by half, the volume of individual particles decreases by 1/8, while the total surface area of the coffee powder increases by 1 time. After coffee beans are ground into fresh coffee powder, their surface area increases exponentially, with the area exposed to air increasing by hundreds or thousands of times.

Once the extremely important acidic fats and volatile fats contained in roasted coffee beans come into contact with air, chemical changes occur, causing both taste and aroma to deteriorate. Among the aromatic compounds in coffee, esters and aldehyde enzymes are most volatile, and their volatilization will cause the coffee's taste to worsen.

Not only does the volatilization and loss of aromatic substances occur, but oxygen in the air also oxidizes aromatic components, especially fats, producing rancid flavors. Freshly ground coffee powder quickly absorbs moisture from the air, increasing weight while reducing the effectiveness of extracting coffee components. Internal molecular pressure further complicates the situation.

Therefore, coffee powder purchased from stores that has been sitting for a long time can probably only be considered as "mummy fragments" of coffee, because much of the coffee powder's flavor has been lost. For a good cup of coffee, never choose convenience by purchasing coffee powder. Grinding fresh and using immediately is the best method.

Furthermore, even with roasted coffee beans, aromatic substances are easily dispersed. Coffee beans that are well-preserved for more than one to two weeks after roasting are already no longer fresh. Therefore, not only should you grind fresh, but also choose freshly roasted coffee beans that are well-preserved whenever possible.

About FrontStreet Coffee

FrontStreet Coffee: A roastery in Guangzhou with a small shop but diverse bean varieties, where you can find various famous and lesser-known beans. They also provide online shop services at https://shop104210103.taobao.com