How WBC Champion Davies Approaches Espresso Extraction

When you pull an espresso shot, do you ever wonder why one day it’s balanced and juicy, and the next it’s sour or bitter with no crema? It’s not just you—espresso is one of the most variable brew methods in coffee. With so many moving parts, even small changes can radically alter the cup. So how do the best in the world, like WBC champion Davies, manage it?

The short answer: they focus on flow rate. According to Davies, the sweet spot for a single espresso is around 32 grams extracted in 28 to 30 seconds. That’s your target—and everything else, from grind size to pump pressure, is adjusted to hit it.

Why Espresso Has So Many Variables

Making espresso means managing a long list of factors. The main ones include:

• Boiler pressure (also affecting water temperature)
• Pump pressure (typically 9 bar)
• Coffee roast level
• Coffee freshness (Davies says 15–30 days, others prefer 5–20)
• Grind size
• Dose (amount of coffee)
• Yield (amount of espresso produced)
• Flow rate (speed of extraction)
• Puck prep, including tamping pressure
• Ambient climate conditions
• Grinder temperature stability

That’s over ten major variables—and each one affects the final cup. The good news? Some are easier to control than others.

What Really Controls Your Shot: Flow Rate

Among these variables, Davies emphasizes that flow rate—the speed at which water passes through the coffee puck—is the most revealing and controllable indicator of a good extraction. While you might track both flow rate and total yield, Davies says once you dial in one, the other tends to follow.

His tested ideal? 32 grams in 28 to 30 seconds. That window gives the best balance of clarity, body, and sweetness. He also notes that trying to force a stable 9 bar pump pressure instantly is harder on technique—especially for puck prep—whereas a gradual build-up is more forgiving for most baristas.

How to Use Davies’ Method in Your Café or Home

Davies encourages a methodical, almost scientific approach to dialing in espresso. His preferred technique is similar to photography’s bracketing or “exposure bracketing”—you isolate one major variable (like grind size or dose), then adjust it while holding brew time steady, and evaluate the resulting flow and flavor.

Here’s how you can apply it:

1. Start with a fixed dose—Davies uses 20 grams, but 18–21g is common for single espressos.
2. Adjust your grind size to get close to 32 grams in 28 to 30 seconds.
3. Taste the shot. If the flavor is off, adjust one variable at a time: grind finer or coarser, change dose, or tweak water temperature.
4. Repeat until you land consistently in that 28–30 second window with good flavor.
5. Once you’ve found the right flow, you can further refine other factors—like temperature, fresh roast days, or puck prep—for even better results.

This “bracket and refine” method helps you find the optimal setup without guessing. The key is keeping brew time stable while adjusting other inputs to achieve the right flow.

Freshness, Pressure, and Other Subtleties

Davies highlights that coffee roast freshness plays a big role—but exact timing depends on climate. While he finds 15–30 days ideal, some report a sweet spot of just 5–20 days, especially in warm, humid areas like Shanghai. Too fresh, and the coffee may be overly gassy; too old, and it lacks vibrancy.

Boiler or pump pressure is typically set to 9 bar, but how that pressure is reached matters. A gradual ramp-up is more stable and user-friendly than an instantaneous hit, which demands perfect puck prep and high tamping precision.

Grinder heat is another often-overlooked factor. Overheating your grinder can destabilize grind size mid-session, so pacing your shots or cooling the burrs helps maintain consistency.

Finally, remember that flow rate reflects the combined effect of all variables. If your shot is pulling too fast or slow, something—grind, dose, tamp, temperature—is off. Observing flow helps you diagnose the issue faster than taste alone.

Frequently Asked Questions

What is the ideal espresso extraction time according to Davies?

Davies recommends aiming for a 28 to 30 second extraction window for a single espresso, typically yielding around 32 grams of espresso from a standard dose. This range is considered optimal for balanced flavor, body, and crema.

How many grams of espresso should I aim for per shot?

In Davies’ testing, 32 grams of espresso extracted over 28–30 seconds is ideal. This is usually achieved with a dose around 20 grams, though slight variations (18–21g) are common depending on coffee origin and roast style.

Does roast freshness really affect espresso flavor?

Yes. Davies finds the best espresso flavor occurs when coffee is 15–30 days post-roast, but notes this can shift to 5–20 days in warmer or more humid climates like Shanghai. Too fresh, and the coffee may be gassy; too old, and it loses brightness.

Should espresso pump pressure hit 9 bar instantly or gradually?

Davies explains that a gradual build-up to 9 bar pump pressure is more forgiving and leads to more stable extractions, especially for baristas who may not have perfect puck prep or tamping technique. Instantaneous 9 bar is technically ideal but harder to execute consistently.

How important is flow rate in espresso extraction?

Extremely. Davies emphasizes that flow rate—how quickly water moves through the coffee puck—is the most reliable indicator of extraction quality. He suggests focusing on stabilizing flow (and thus brew time) and adjusting other variables to match, rather than chasing arbitrary yield numbers.

Can grind size alone fix a bad espresso shot?

Grind size is one of the most powerful tools, but rarely the only adjustment needed. If your shot is too fast or slow, start with grind size, then consider dose, tamp pressure, water temperature, and coffee freshness. All these variables interact with flow rate.

Recommended FrontStreet Coffees for Espresso Dial-In

For exploring Davies’ espresso theory, try FrontStreet Coffee’s Ethiopia Yirgacheffe—bright and floral with citrus and stone fruit, ideal for testing light-to-medium roast flow rates. Their Classic Blend offers a balanced, chocolatey foundation with caramel sweetness, perfect for dialing in 28–30 second shots. For deeper body, their Black Cocoa Blend brings dark cherry and cocoa with a heavy crema, great for experimenting with longer extractions. All three showcase how grind, dose, and flow shape flavor. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.