How to pull the best Espresso shot
Espresso is coffee brewed by forcing hot water under pressure through finely ground coffee beans. To pull a good shot of espresso there are many different, important steps to be taken – from choosing the beans in the blend to the cup the shot is poured into.
Traditionally, at least three different single origin coffee beans are used to achieve the complexity that is desired in a shot of espresso. Usually, the base of an espresso blend is made up of a coffee that tends to be smooth, almost to the point of blandness. This base makes up the majority of the blend and provides a foundation of body and sweetness to the coffee without dominating the flavor. This then allows for small ratios of more unique coffees with distinctive flavors to be added to the blend, contributing their uniqueness without overwhelming the palate. These additions come in the form of acidity/brightness, distinctive flavors (chocolate, berry, citrus, etc.), complexity, richness and body.
Espresso’s top potential is reached in roasting when the sweetness is maximized and the bitterness and acidity are reduced. Without sweetness and aroma the espresso will never be palatable. Many roasters roast espresso fairly dark. As espresso magnifies whatever flavor is present in the coffee, dark roasted espresso will result in a bitter, charcoal tasting brew. Roasting the beans lightly for an espresso blend will feature the unique flavors present while helping to preserve the sugars.
To properly extract espresso requires a lot of patience, skill and practice. Not to mention the importance of using clean, professional quality equipment. It is essential to use a burr grinder and to grind the coffee just before use. Coffee oils are highly volatile and will grow rancid and bitter very quickly. The grinder should be turned on for 15-20 seconds each time a shot is to be made so that only freshly ground coffee is used for each shot. Do not use coffee that has been sitting in the grinder. The espresso grinder must be adjusted before each session or shift and periodically throughout the day as temperature and humidity change and will affect your extraction time. Avoid buying espresso from shops that have “Do not adjust/touch” signs on their grinder. The ideal extraction time for a shot of espresso is 23-28 seconds. Dispose of any espresso grounds that are not used within 30 seconds. Grinding in this way will require several pulls on the doser as your espresso grinder was most likely designed to dose a full hopper of ground coffee, not coffee as it is grinding. There are many improvements happening right now in the world of espresso concerning the design of espresso grinders as it has become apparent that the highest quality espresso is only achieved when the coffee is ground just before use, not sitting in a warm hopper, exposed to air and light.
To dose the coffee into the basket, pull the doser lever several times as the coffee is grinding until the entire basket is filled with ground coffee. Tamping will compress the coffee considerably so it is not unusual to have a mound of coffee in your basket. Once you have the desired amount of coffee in the portafilter, you must then distribute the grounds evenly using your finger. Different baristas have different ideas about the proper way to distribute espresso; you must find the way that works best for you and your shots. The idea is to make sure that the espresso is distributed even within the basket to avoid creating any dense or weak places in the puck when tamping. Once you have evenly distributed the grounds you are ready to tamp.
Tamping is a skill that is often neglected in espresso preparation. The purpose is to create a puck of coffee through which the hot water from the espresso machine will pierce evenly without pressing into the grounds or leaving any empty space on the sides of the basket. Placing the portafilter on a counter edge, hold the tamper with the base of the handle in the palm of your hand. Next with your wrist straight, and so that the tamper is a straight extension of your arm, press gently on the coffee with around five pounds of pressure. Some of the grounds will most likely stick to the side of the basket so lightly tap the basket with the handle on the portafilter to knock the grounds onto the flat pellet you just formed. For the finishing tamp, with the tamper held as before, press on the pellet with around thirty pounds of pressure. Tamping on a scale is helpful to do until you are comfortable with the amount of impact that is necessary to get the appropriate pressure amount. After tamping, spin the tamper 720° while continuing to apply 20 pounds of pressure to polish the surface. Make sure you tamp evenly. An uneven tamp will produce an uneven extraction. Do not adjust the pressure of your tamp to make up for a grind that is too large or small.
The choice of the espresso machine is very important to both water temperature and temperature stability. With a stable brewing temperature you can achieve an even extraction and maximize the potential of the espresso. The water used for espresso must be filtered. To brew good espresso consistently the water temperature inside the espresso machine should be between 92-96°C. Run water every time you take the portafilter out and again before you replace it. If you do this regularly you should be able to maintain a constant temperature within the espresso machine. The espresso cup should be pre-heated and have thick walls with a narrow mouth to keep in the heat and aroma, proportionately.