Definition and brew parameters
The definition of espresso and the key parameters that govern its preparation.
- Coffee Basics Nerds
- 1 min read
Article 1 of 12 in Espresso Fundamentals/
What is Espresso?
- Definition: A concentrated coffee beverage brewed by forcing hot water under pressure through a compacted puck of finely ground coffee.
- Distinctive Features:
- Crema: golden foam of emulsified oils and gases.
- Intensity: strong flavor, high body, small volume.
- Brewed quickly (20–35 seconds).
Core Brew Parameters
- Dose: 16–20 g of ground coffee (typical double shot).
- Yield: 30–45 g beverage weight.
- Ratio: Commonly 1:2 (e.g., 18 g in → 36 g out).
- Time: 25–30 seconds ideal extraction window.
- Water Temperature: 90–96 °C (195–205 °F).
- Pressure: ~9 bars of pump or lever pressure.
Extraction Targets
- TDS: 8–12%.
- Extraction Yield (EY): 18–22%.
Flavor Outcomes
- Balanced espresso → sweetness, acidity, and body in harmony.
- Under-extracted → sour, sharp, thin.
- Over-extracted → bitter, harsh, hollow.
Summary
Espresso is defined by high pressure, fine grind, and short contact time. Key parameters—dose, yield, ratio, time, temperature, and pressure—determine whether the resulting shot achieves balance, intensity, and crema characteristic of true espresso.