Unlocking the Espresso Secret
Beyond the 1:2 ratio: Understanding extraction, yield, and strength.
Thiha Aung
Contributor
Espresso is often misunderstood as simply 'strong coffee.' In reality, it is a complex suspension of oils, gases, and solids, forced into existence by 9 bars of pressure. To master espresso is to master the physics of water meeting resistance.
While most beginners focus on the 'look' of the crema, seasoned baristas look at the numbers. Total Dissolved Solids (TDS) and Extraction Yield are the true north stars of a great shot. In this guide, we break down the three distinct phases of a shot and how to manipulate them to achieve the perfect balance of sweetness and acidity.
The Three Phases of Flavor
As water passes through the coffee puck, it extracts compounds in a specific order. The first third of the shot (The Ristretto phase) is high in acidity and saltiness. The middle third brings the sweetness and sugars. The final third (The Blonde phase) introduces bitterness and astringency. Understanding this timeline allows you to 'cut' your shot at exactly the right moment to capture the sweetness while leaving the harsh bitterness behind.
The Essential Variables
Adjust these four variables one at a time to dial in your perfect recipe.
Dose
The dry weight of coffee. For modern espresso, we recommend 18g to 20g in a precision basket.
Yield
The liquid weight in the cup. A standard 1:2 ratio means 18g in, 36g out.
Time
The duration of the pump. Ideally, your yield should be reached within 25 to 30 seconds.
Temperature
Set your boiler to 93°C (200°F). Lighter roasts benefit from slightly higher heat to aid extraction.
Signs of Uneven Extraction
- Channeling: Small holes in the puck that lead to a watery, sour taste.
- Tiger Striping: While beautiful, inconsistent striping can indicate a poor tamp.
- Muddy Puck: Often a sign that your grind is too fine or your basket is underfilled.
- Lingering Bitterness: The tell-tale sign that you have 'over-extracted' the grounds.
The Importance of Water
Espresso is 98% water. If your water is too 'hard' (high mineral content), it will clog your machine and dull the flavor. If it's too 'soft,' it will taste flat and lack body. We recommend using filtered water with a mineral content of roughly 150ppm to allow the coffee's natural brightness to shine through.
