Milling:

One of the most important steps in making a great espresso is to grind the coffee beans to the right size. Grinding the beans too finely or too coarsely can result in a cup of coffee that is too bitter or too weak. As a result, you’ll find issues of flow being too slow or too fast, respectively.

When you grind coffee beans, you break them down into smaller pieces that will be brewed to make the coffee. Different brewing methods require different grind sizes, so it's important to choose the right size for your espresso machine. When you grind the coffee, you want to aim for a consistency that is similar to table salt.

Mix:

Espresso is made by forcing hot water through finely ground coffee beans at high pressure. To create a delicious espresso, it's important to choose the right blend of coffee beans. Coffee beans from different regions and countries have different flavors and aromas, and they can be blended together to create a unique and complex flavor profile. When you're selecting coffee beans for your espresso, you'll want to consider factors like the roast level, the origin of the beans, and the flavor notes. A skilled barista can create a custom blend of coffee beans that is perfectly suited to your tastes. Coffee beans that are too old will not provide crema or great flavor. Crema is solidified CO2 gas suspended in the water.

Machinery:

The espresso machine is the most important piece of equipment for making a great espresso. Espresso machines use high pressure and hot water to extract the flavor and aroma from the coffee beans, and they require precise control to achieve the perfect balance. There are many different types of espresso machines available, from manual machines that require a high level of skill to operate to fully automated machines that can make espresso at the touch of a button. When you're choosing an espresso machine, you'll want to consider factors like the price, the features, and the level of control that you want over the brewing process.

Mastery:

Making a great espresso requires skill and technique. A skilled barista knows how to control the variables that go into making a great espresso, like the temperature of the water, the grind size of the coffee beans, and the pressure of the machine. They also know how to adjust the brewing process to create the perfect flavor profile for each individual cup of espresso. If you're new to making espresso, it's important to learn the basics of the brewing process and to practice your technique until you feel confident in your skills. With time and practice, you can become a master of the art of espresso-making.