If you’re a coffee lover, you probably already know that espresso is the foundation for many popular coffee drinks. But what exactly do extraction and tamping have to do with creating a perfect cup of espresso? Let’s explore the science behind espresso to understand how these two elements are essential for making great espresso.
What is Extraction?
Extraction is the process of pulling flavor out of ground coffee beans. When hot water passes through freshly ground coffee, it draws out compounds like caffeine, proteins, and oils that give espresso its unique flavor. The ideal extraction rate will yield an evenly balanced cup of espresso with no bitter or sour notes. To achieve this, baristas carefully measure out specific quantities of coffee and grind size to ensure that all the flavors are properly extracted from the beans.
To determine if an espresso shot has been properly extracted, baristas use a refractometer to measure Total Dissolved Solids (TDS). The TDS measures the strength of an espresso shot by measuring how much soluble material is dissolved in it—the higher the number, the stronger the shot. Ideal extraction should fall between 0.85-0.93% TDS for a single shot or 1.45-1.65% TDS for a double shot.
What is Tamping?
Tamping is another key element in creating great espresso shots—it involves pressing down on freshly ground coffee in order to compact it into a puck shape before brewing begins. This helps create even pressure during extraction so that all of the grounds are exposed to hot water at once instead of some being over-extracted while others remain under-extracted due to uneven distribution within the portafilter basket. A well-tamped puck also creates resistance which helps regulate flow rate during extraction; too little resistance can result in an overly fast flow rate which leads to weak shots whereas too much resistance can lead to over-extraction and bitter shots. Professional baristas often spend hours practicing their tamping technique in order to achieve optimal results every time they pull shots.
Making great tasting espresso requires precision from start to finish – from grinding fresh beans and carefully measuring them out, all the way up until tamping them down into a perfectly shaped puck before brewing begins. With experimentation and practice, any home barista can learn how to master extraction and tamping for delicious drinks every time. So next time you make yourself an espresso drink – take note of each step in order to get your own perfect cup.