Researchers are challenging common espresso wisdom, finding that fewer coffee beans, ground more coarsely, are the key to an espresso that’s cheaper to make, more consistent from shot to shot, and just as strong.
While coarser grounds and a shorter shot time produce a consistent result that’s just as strong, the traditional method does provide a more complex flavor imparted by partially clogged flow. This is caused by some portions of the grounds undergoing less or more extraction, which can bring out different flavors.
One way to optimize extraction and achieve reproducibility is to grind coarser and use a little less water, while another is to simply reduce the mass of coffee.
Reducing the amount of coffee increases the extraction yield, since the extra room in the coffee bed allows for the water to brew more of the coffee. This means a barista can use 15 grams of coarsely ground coffee and still achieve consistent espresso with the same punch as the standard 20-gram espresso shot. This modification can result in very fast shots of less than 15 seconds, a higher espresso concentration and a different flavor profile.
Faster shot times happen when brewing coarser grounds because there is more space in the coffee bed for the water to move through.