Is it the Bean?
No. Inaccurate marketing and erroneous word of mouth have given many people the impression that the type of bean determines whether the brew is espresso or not. This is not true. Any type of bean can be used to make good espresso coffee.
Is it the Blend?
No. Although there are blends designed specifically for espresso, the blend does not make it espresso. The pursuit of the perfect blend for making espresso coffee has led to this common misconception. Some roasters might even argue that you can only make a good espresso with the right blend. 1st in Coffee offers a variety of espresso blends from illy, Lavazza and Segafredo.
Is it the Roast?
No. Popular thought might lead you to believe that espresso must be an extremely dark roast; however the espresso roast varies from region to region. In California, you would be most likely to encounter a dark or "French" roast. On the east coast of the US, a light roast is often preferred. And in Northern Italy, a medium roast is generally used. Any roast can be used to make good espresso. It is entirely a matter of taste.
Espresso distinguishes itself however, with the drastically different method by which it is made. Espresso is prepared by forcing hot water through finely ground coffee at high pressure. The temperature and pressure of the water emulsify flavorful oils from the coffee. Additionally, because the environment is highly pressurized, the espresso becomes supersaturated with micro bubbles of carbon dioxide extracted from the grounds, some of the oils cling to these bubbles and become crema.