An espresso is a small, concentrated coffee made by forcing hot water through finely ground coffee under pressure. A typical double uses about 18 g of coffee and gives roughly 36–40 g of liquid.
What to look for
- Balance. Sweetness, acidity and bitterness should sit together. No single one should shout.
- Body. Good espresso feels thick and syrupy, not watery.
- Crema. The hazel-brown foam on top. Nice to see, but it isn't proof of quality: very fresh or robusta-heavy coffee makes lots of crema too.
- Finish. A pleasant aftertaste, not a dry, harsh one.
The 25-second myth
Baristas often aim for 25–30 seconds, but it's a starting point, not a rule. A shot is right when it tastes right. Sour and thin usually means under-extracted (too fast or too coarse). Harsh and bitter usually means over-extracted.
Try this at a cafe: order the espresso before a milk drink. It tells you more about the beans and the barista than anything else on the menu.