Understanding and Preventing Sourness in Espresso

The sour taste in espresso often comes from under-extraction. This process pulls out acidic compounds early on, leaving the coffee tasting sharp and tangy. Surprisingly, different factors can influence this, not just the beans or grind size.

A lower water temperature can lead to sour espresso. Optimal brewing temperature is between 195-205°F (90-96°C). Below this range, the coffee's acids are extracted more readily, enhancing sourness instead of achieving a balanced flavor profile.

Finely ground coffee increases surface area, leading to faster extraction. However, if the grind is too coarse, the water flows too quickly, under-extracting the coffee. This under-extraction releases more acidic compounds and results in a sour taste.

The ideal extraction time for espresso is 25-30 seconds. Anything shorter can lead to sourness due to insufficient extraction. Interestingly, even a difference of a few seconds can dramatically alter the taste, making it crucial for achieving balance.

Surprisingly, overly fresh beans can make espresso sour. Freshly roasted beans release CO2, which can interfere with extraction. Waiting a few days post-roast allows gases to escape, leading to a more balanced and less sour espresso.

Espresso beans grown at higher altitudes tend to be more acidic. The cooler temperatures slow down coffee cherry maturation, leading to higher acidity and a brighter flavor profile.