It's brewing and coffee time
Espresso coffee, as its name implies, uses specific dosages of coffee during preparation. Years ago this used to be 7 grams per cup. Today, however, the use of specialty coffees, shorter toasting curves and lighter toasting colours has increased this value to 16 grams +/- 2 grams for two cups, as long as grain size and percolating times are respected.
Tamping ground coffee with a tamper restricts water flow, forcing the coffee and water to interact at the right pressure. Tamping should be firm and even, aiming to compact the coffee perpendicular to the filter without applying unnecessary force.
Pre-infusion is when you gently soak the puck of ground coffee in the filter before applying the full desired brewing pressure. The goal here is to ensure that water evenly penetrates the grounds so that the entire bed has the same amount of water flowing through it once extraction begins. This method tends to work quite well and evens out the water flow, extracting as much as possible from all of the coffee.
Extraction: a balancing act
When you make your cup of coffee, pressurized hot water is percolated through a layer of roasted, ground and compacted coffee to extract the drink we know and love, which then flows out from the filter spouts and into your cup. The way coffee is extracted defines the quality of the final result, the thickness of the cream on the surface and the fine and persistent texture.
Extraction is a balancing act. Ideally, you want to avoid under extraction, when the water passes too fast through coarse grains and doesn’t have time to capture all the precious substances, or over extraction which is exactly the opposite.