Four variables: 18 g of coffee, yielding 36 g of espresso in 25–30 seconds at 92–94 °C. Tastes sour? Grind finer. Tastes bitter? Grind coarser. Always change only one variable at a time.

How do I make the perfect espresso?

Four variables: 18 g of coffee, yielding 36 g of espresso in 25–30 seconds at 92–94 °C. Tastes sour? Grind finer. Tastes bitter? Grind coarser. Always change only one variable at a time.

Why that is

Espresso is the most demanding coffee brewing method — and simultaneously the most predictable, once you understand the variables. Four parameters dictate the outcome:

1. Grind size — your biggest lever. It regulates how fast water flows through the puck and how much is extracted. Too fine = too slow = bitter. Too coarse = too fast = sour and watery. The grind size is the very first thing a barista adjusts.

2. Dose — the amount of ground coffee in the portafilter. The standard for a double espresso: 18 g (range: 16–20 g, depending on the basket and machine). The dose determines strength and body. Once dialed in, you rarely change it.

3. Brewing temperature — 92–94 °C for most roasts. Light roasts can take more heat (94–96 °C), dark roasts need less (90–92 °C). The temperature influences which compounds are extracted: sugars and fruit acids extract better at lower temps, while bitter compounds extract at higher temps.

4. Extraction time — the result of the first three variables. The target: 25–30 seconds for a double espresso (a 1:2 ratio, meaning 18 g in, 36 g out). You control the time indirectly by adjusting the grind size.

The starting recipe:

1. Dose 18 g of freshly ground coffee into the portafilter
2. Distribute it evenly (using a WDT tool or a finger-tap)
3. Tamp perfectly level with consistent pressure
4. Lock the portafilter into the group head, place a scale under the cup
5. Start the shot, start the timer
6. Stop the shot right as you hit 36 g in the cup
7. Was the time between 25–30 seconds? If yes: taste it. If too fast: grind finer. If too slow: grind coarser.

The golden rule of troubleshooting: always change only one variable at a time. If you change both the grind size and the dose at the same time, you’ll never know which change actually made the difference. Optimizing espresso is systematic work — small steps, taste every time, note the results.

Perfection is a moving target: fresh beans need a different grind size than older ones, and warm weather demands a different setting than cold weather. The “perfect” espresso is not a fixed state, but an ongoing process.

In practice at Green Wall Coffee

At Sophienstraße 27, I start every morning by dialing in the grinder. The very first cup goes straight down the drain — it’s the test run. After that, I pull 2–3 shots, tasting and adjusting until the extraction is spot on. For guests making espresso at home, I tell them: buy a scale (starts at 15 euros) and a timer. Without those two tools, making espresso is just guessing instead of a craft.

Related questions

• What are the four most important variables in espresso preparation?
• Why does my espresso taste bitter?
• Why does my espresso taste sour?

You can find more in-depth information in the article How to make perfect espresso. Or drop by Sophienstraße 27 — Mon–Fri 8am–5pm, Sat 10am–5pm.