What is an espresso?

Could you please explain what an espresso actually is? I’m curious about how it’s made, what makes it different from regular coffee, and why it’s considered the base for so many other coffee drinks like lattes and cappuccinos. Also, if possible, describe its flavor profile and texture compared to other brewing methods.

Espresso is a concentrated coffee beverage brewed by forcing a small amount of nearly boiling water under pressure through finely-ground coffee beans. It is characterized by its thick consistency and rich, bold flavor with a layer of reddish-brown foam called "crema" on top, which forms due to emulsification of coffee oils and gases.

Preparation and Equipment

• Grind: Coffee beans are ground to a fine, powdery consistency, similar to powdered sugar.
• Dose: A typical shot uses 7–18 grams of coffee, depending on the machine and desired strength.
• Extraction Hot Water: Water is heated to 90–96°C (194–205°F) and forced through the coffee at 8–10 bars (116–145 psi) pressure for 20–30 seconds.
• Yield: A standard single shot (1 oz or 30 ml) or double shot (2 oz or 60 ml) yields approximately 1/4 to 1/2 cup of liquid.

Characteristics

• Flavor Profile: Intense, full-bodied, and aromatic, with notes of caramel, chocolate, or fruitiness depending on the bean origin and roast. Bitterness is balanced by acidity.
• Crema: A golden-brown foam (1–4 mm thick) that retains aroma and acts as a protective layer for espresso’s volatile compounds. It dissipates within 10–15 minutes.
• Caffeine Content: Despite being a small volume, espresso is highly caffeinated (approx. 63 mg per ounce), though concentrated.

Cultural and Practical Significance

• Base for Drinks: Serves as the foundation for lattes, cappuccinos, macchiatos, americanos, and more by adding steamed milk, foam, or hot water.
• Caffeine Ritual: Central to Italian café culture ("bar"), where it is consumed quickly, often standing, to savor freshness.
• Barista Expertise: Requires skill in grinding dosing, tamping (compressing coffee evenly), and timing to avoid under-extraction (sour) or over-extraction (bitter).

Variations

• Ristretto: Shorter extraction (15–20 ml) using the same coffee dose for a sweeter, less intense shot.
• Lungo: Longer extraction (60–90 ml), resulting in a milder, diluted coffee.
• Doppio: Double-sized espresso shot (about 2 oz).

Historical Context

Invented in Milan, Italy, in the early 20th century, espresso machines evolved from Luigi Bezzerra’s 1901 patent to modern designs like the Faema E61 (1961), which introduced continuous pressure.

Espresso’s unique brewing method maximizes extraction efficiency, capturing soluble solids and volatile oils that define its distinctive taste and sensory profile.