How to Make Coffee: From Bean to Espresso

Making a great cup of coffee isn’t just about pressing a button or boiling water. Whether you’re pulling a shot of espresso or brewing a pour-over, the quality of your coffee depends on three fundamentals: the beans, the equipment, and your technique. If any one of these is off, your coffee won’t reach its full potential. So how do you get it right?

To make a proper espresso, use 6–7 grams (about 50 beans) of coffee, extracted at 92°C ±2° under 9 atmospheres for 25–30 seconds, yielding 30cc of liquid. That’s the baseline for quality extraction.

Understanding Coffee Varieties: Arabica vs Robusta

There are two main commercial coffee species: Arabica and Robusta. Arabica grows at higher altitudes, typically on slopes, which limits production and makes it more expensive. It’s handpicked, resulting in higher quality but lower yields. Robusta, on the other hand, grows on flat land and can be harvested by machine, which lowers costs and increases output. Its higher caffeine content makes it more bitter and resistant to pests, but also less nuanced in flavor.

Arabica generally has lower caffeine (making it less bitter and more susceptible to pests), while Robusta has more caffeine, contributing to a harsher, more bitter taste. Processing methods differ too: Robusta is often processed with the dry method—fruits and beans are dried together, sometimes picking up unwanted flavors. Arabica is typically washed, ensuring cleaner, brighter flavors but requiring more labor and time.

In China, Robusta sells for around 7 RMB per kilogram, while Arabica fetches up to 70 RMB per kilogram, reflecting their respective quality and production costs.

Coffee Roast Levels and Freshness

Coffee is roasted in eight general stages, divided into light (2 stages), medium (3), and dark (3). Light roasts are pale in color, medium roasts are red-brown, and dark roasts are black and oily. Darker roasts produce stronger flavors, but also mask the bean’s origin characteristics. For the best flavor, let freshly roasted coffee rest for about 48 hours before brewing—the flavors stabilize during this “degassing” period.

Roasted coffee is best stored in aluminum bags with nitrogen for 2–3 years. Without nitrogen, shelf life drops to a month, and even high-quality vacuum-sealed bags last only around three months. Ground coffee loses 20% of its aroma instantly upon grinding and deteriorates much faster than whole beans. The drying level of beans also affects extraction—on average, one kilogram of green coffee loses 3–4 liang (150–200g) of moisture during roasting, leaving about 6 liang (300g) for brewing, which yields roughly 90 cups.

The ideal serving temperature is between 65–75°C. A single cup uses 6–7 grams of coffee (around 50–55 beans). The human body contains 100–500 mg of caffeine; below 100 mg, you may feel tired, while over 500 mg can cause overstimulation, increased heart rate, and blood vessel dilation.

How to Extract Coffee: Methods and Best Practices

The most effective home extraction method is the espresso, made using an espresso machine. A proper espresso shot is the foundation of many coffee drinks and highlights the bean’s best qualities. Here’s how to do it right:

• Coffee dose: 6–7 grams (≈50 beans)
• Water temperature: 92°C ±2°
• Pressure: 9 atmospheres (ideal range: 9–15 bar)
• Water volume: 30cc (±5cc)
• Extraction time: 25–30 seconds

The grind size matters—a finer grind increases resistance and extraction time, risking over-extraction and bitterness. A coarser grind reduces resistance, leading to under-extraction and weak flavor. Pressure and flow rate must be balanced. External factors like tamping consistency and machine calibration also affect results.

For comparison, drip or filter coffee (without pressure) extracts more caffeine—about 360 mg per cup vs 80 mg in espresso—but often lacks the balance and intensity of a well-pulled shot. Pump-driven machines control temperature and pressure better than basic drip or moka pots, which can scorch coffee or produce uneven extractions.

Coffee Equipment: Types and Functions

Electric coffee machines fall into six main types:

• Automatic espresso machines: Grind, tamp, brew, and clean automatically. Some, like De’Longhi models, feature patented systems like IFD for milk texture control.
• Pump-driven espresso machines: Heat water to 92°C and pressurize it to 15 bar to force water through packed coffee, producing espresso.
• Drip filter machines: Heat water in a tank, then let it drip through ground coffee by gravity into a carafe. No pressure is used, resulting in lighter extraction.
• Percolator-style machines: Circulate boiling water through coffee grounds repeatedly. Temperature control is limited, often leading to over-extraction or burnt flavors.
• Moka pots: Use steam pressure to push water through coffee in a stovetop setup. Made of aluminum or stainless steel, they produce strong, concentrated coffee similar to espresso but not true espresso.
• Siphon (vacuum) brewers: Use vapor pressure and vacuum to brew coffee in two chambers. More theatrical than practical, and require careful technique.

Among these, espresso machines offer the most control over pressure, temperature, and dose—key factors in quality extraction. Simpler methods like drip or moka lack precision but can still produce decent coffee with the right beans and care.

Frequently Asked Questions

What’s the ideal coffee-to-water ratio for espresso?

A standard single espresso shot uses 6–7 grams of coffee and 30cc (milliliters) of water. This equates to roughly a 1:2 to 1:3 brew ratio (coffee mass to water volume), typical for espresso. Adjust based on taste preference and bean origin.

What’s the best grind size for espresso?

The grind should be fine, similar to powdered sugar or table salt. It needs to be fine enough to create enough resistance for water under 9 bars of pressure, allowing proper extraction in 25–30 seconds. Too coarse leads to under-extraction; too fine causes over-extraction and channeling.

Can I use Robusta beans for espresso?

Yes, Robusta can be used for espresso, especially in blends, to add body and crema. However, it has higher bitterness and caffeine content. Many baristas prefer Arabica for its sweetness and complexity, but a small percentage of Robusta is common in traditional Italian blends.

How long should coffee beans rest after roasting?

For best flavor, let roasted coffee beans rest for about 48 hours. This allows CO₂ built up during roasting to dissipate, leading to more stable and flavorful extractions. Freshly roasted beans can taste too intense or uneven before this degassing period.

What water temperature is best for brewing espresso?

The optimal water temperature for espresso is 92°C, with an acceptable range of 90–94°C. Too hot can over-extract and burn the coffee; too cool leads to under-extraction and sour flavors. Consistent temperature is key for balanced shots.

How does grind size affect coffee extraction?

Grind size controls the brew time and extraction efficiency. Fine grinds slow water flow, increasing contact time and extraction (good for espresso). Coarse grinds speed up flow, reducing extraction (better for French press or cold brew). Always adjust grind to match your brewing method and desired strength.

Recommended FrontStreet Arabica Beans for Brewing

For excellent brewed coffee, try FrontStreet’s Ethiopia Yirgacheffe Gedeb Cooperative—bright with citrus and floral notes, perfect for pour-over. Their Jamaica Blue Mountain No.1 (Typica) offers a balanced, smooth profile with hints of chocolate and nuts, ideal for drip or French press. Also consider the Brazil Queen Manor Yellow Bourbon, which delivers creamy peanut and caramel tones when brewed medium-dark. All are high-quality single origins that highlight the craft of brewing. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.