So often I walk into a cafe and there it is for all to see on the grinder. It's the gospel according to the Oracle who decides how the coffee should be - and yet? So often, bitterly (or was that sourly) disappointing…
For years, brew ratios, shot times, and yield numbers have been treated like sacred coordinates. This many grams in, that many out for an X:Y brew ratio. This many seconds to get that many grams out. Stamp it, ship it, do not question it - and yet, the espresso? Sub-par.
There IS a Case Against Treating the Science as Gospel
The Scientist in me questions the recipe…
- What were the environmental conditions on the day that the recipe was decided?
- How many days after roasting was that, and how was the coffee stored post-roast?
- If the espresso tastes bad, then what? Blame the roaster? The barista? The hygiene? The hardware?
The Case Against Strict Brew Metrics
1. Numbers Can Become a Crutch
A 1:2 ratio in 25 seconds tells you nothing about how the espresso tastes. You can hit every "correct" metric and still end up with a cup that tastes like burnt toast arguing with lemon peel. Likewise TDS (Total Dissolved Solids).
Espresso is a sensory craft. Palate wins. EVERY time.
2. Beans Are Not Identical
A dense light roast Ethiopian and a syrupy Brazilian natural will behave very differently at the machine. Attempting to force each into the same ratio and time window is going to deliver tears. It just doesn't work.
Light roasts might shine at longer brew ratios like 1:2.5 or even 1:3. A dark roast may well taste better with tighter ratios like 1:1.5. Not the same rules.
3. Shot Time Is a Result, Not a Goal
Time is a symptom of grind size and flow, not a flavour guarantee. If you chase 25 or 30 seconds and ignore the taste, you're optimising for a number, not a cup.
4. Pressure, Altitude and Equipment Vary
The same dose and ratio will produce different results on a machine with 9 bar pump pressure versus one with 6 bar, or on a commercial machine with a pre-infusion step versus a home machine without. Blanket rules fail to account for these variables.
So What SHOULD You Do?
Use ratios and times as a starting point, not a destination.
Start with something reasonable (say 18g in, 36g out over 28 seconds), taste the espresso critically, and adjust from there. Is it sour? Grind finer. Is it bitter? Grind coarser. Is it watery? Reduce yield or grind finer. Too intense? Extend the yield.
Trust your palate. It is the only instrument that matters in the cup.