Problem Cause
Under-extraction
Water hasn't extracted enough soluble compounds from the coffee, leaving behind desirable flavors
How to Identify This Issue
- 1Extraction time under 22 seconds
- 2Sour or acidic taste
- 3Thin, watery body
- 4Pale or blonde crema
- 5Shot runs too fast
Visual Cues
Ground texture and uniformity
Puck surface and distribution
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Solutions for Under-extraction
Grind Finer
Adjust your grinder to produce finer coffee particles. Make small adjustments (2-3 increments on most grinders) and pull a test shot.
Expected Result
Extraction time should increase by 3-5 seconds. Flavor should become more balanced with less sourness.
Increase Extraction Yield
Pull a longer shot, increasing your output ratio. Try moving from 1:2 to 1:2.5 (e.g., 18g in → 45g out instead of 36g).
Expected Result
More extraction, reduced sourness, sweeter and more balanced flavor.
Increase Coffee Dose
Add 0.5-1g more coffee to your portafilter basket. Ensure it's within your basket's recommended capacity.
Expected Result
More resistance, slower extraction, fuller body and more intense flavor.
Preheat Machine Properly
Allow your espresso machine to heat for at least 20-30 minutes. Run water through the group head before your first shot.
Expected Result
Stable brewing temperature, more consistent extraction, better flavor development.
In-Depth Guide
What under-extraction means
Under-extraction happens when water doesn’t dissolve enough compounds from the coffee. The result often tastes sharp, sour, thin, or hollow.
Why it happens
Most commonly:
- Grind is too coarse
- Shot time is too short
- Temperature is too low
- Dose is too low or yield is too low for the coffee
How to confirm
Look for a combination of:
- Fast flow (often < ~22s for a typical double)
- Pale/blonde crema early
- Thin body, “watery” texture
- Acidity without sweetness
Fixes (recommended order)
- Grind Finer (small steps)
- Increase yield slightly (extract a bit more)
- Ensure the machine is fully warmed and stable
FAQ
Q: Is under-extraction always sour? Often yes, but it can also show up as “hollow” or “empty” even without sharp acidity.