While the title is not regulated, coffee shops use the title barista to describe the preparer of coffee and operator of an espresso machine.
Good espresso-making is essential to a barista's role. Latte art is a visible sign of a trained barista and well-frothed milk.
Baristas generally operate a commercial espresso machine, and their role is preparing and pulling the shot; the degree to which this is automated or done manually varies significantly, ranging from push-button operation to an involved manual process. Espresso is a notoriously finicky beverage, and good manual espresso making is considered a skilled task. Further, preparation of other beverages, particularly milk-based drinks such as cappuccinos and lattes, but also non-espresso coffee such as drip or press pot, requires additional work and skill for effective frothing, pouring and most often latte art.
The barista usually has been trained to operate the machine and to prepare the coffee based on the guidelines of the roaster or shop owner, while more experienced baristas may have discretion to vary preparation or experiment. To make the coffee well, there is a series of steps needing attention, including grinding the beans, extracting the coffee, frothing the milk and pouring.
Beyond the preparation of espresso and other beverages and general customer service, skilled baristas acquire knowledge of the entire process of coffee to effectively prepare a desired cup of coffee, including maintenance and programming of the machine, grinding methods, roasting, and coffee plant cultivation, similar to how a sommelier is familiar with the entire process of wine making and consumption. A barista can acquire these skills by attending training classes, but they are more commonly learned on the job.