Ratio is one of the strongest levers in espresso. It controls concentration and extraction balance more directly than most users expect.
What ratio means
Brew ratio is beverage weight divided by dry coffee dose. An 18g dose and 36g yield is a 1:2 ratio.
Lower ratios are more concentrated and syrupy. Higher ratios are lighter and often clearer.
Where to start
For medium roasts, start at 1:2. For lighter roasts, 1:2.2 to 1:2.5 can increase clarity and sweetness.
For darker roasts, 1:1.8 to 1:2 often reduces harsh bitterness.
How to adjust by taste
If shots are sour and salty, extend yield slightly. If shots are bitter and dry, shorten yield.
Move in small steps like plus or minus 2g out and retest.