The Coffee Compass is a two-axis diagnostic tool created by Matt Perger at Barista Hustle for dialing in filter brews. It maps taste problems to concrete adjustments.
Vertical — Strength: too strong (intense, overpowering) ↔ too weak (watery, thin)
How to use it
Brew a cup
Identify the dominant off-flavor
Locate it on the compass
Follow the arrow back toward the center (“ideal” zone)
Adjust one variable at a time — grind size first, then temperature
Adjustment directions
Direction
Action
Extract more
Grind finer and/or increase water temperature
Extract less
Grind coarser and/or decrease water temperature
Increase strength
Use more coffee or less water (tighter ratio)
Decrease strength
Use less coffee or more water (looser ratio)
Quick reference
Taste
Diagnosis
Primary fix
Sour, sharp, lemony
Under-extracted
Grind finer
Bitter, harsh, drying
Over-extracted
Grind coarser
Weak, watery, flat
Too dilute (strength)
Tighter ratio
Intense, overpowering
Too concentrated
Looser ratio
Sour and bitter together
Uneven extraction
Fix technique (channeling)
Salty, quick finish
Severely under-extracted
Grind much finer
Astringent (tea-like dryness)
Over-extracted
Grind coarser, lower temp
Key insight
Grind size is the primary dial-in variable. Adjust temperature only after grind changes plateau. Ratio controls strength, not extraction — change it when the flavor character is right but the intensity is off.