# The Coffee Compass, a simple way to fix a bad brew

> When filter coffee tastes off, the fix usually isn't a mystery. A simple diagnostic framework from Barista Hustle tells you exactly which direction to adjust.

By Joey Krosch. Published 2024-03-14, updated 2026-08-17.

When a filter coffee tastes wrong, too sour, too bitter, oddly harsh, the
temptation is to change everything at once and hope. The Coffee Compass,
developed by Matt Perger and the team at Barista Hustle, gives you a
simpler, more direct way to diagnose the problem and fix specifically
that.

## The four quadrants

The framework maps how a cup tastes onto four zones, and each one points
to a specific, correctable cause:

**Sour and lacking sweetness**: under-extraction, not enough has been
pulled from the grounds yet.

**Bitter and astringent**: over-extraction, too much has been pulled,
including compounds you don't want.

**Salty or harsh**: uneven extraction, different parts of the coffee bed
extracted at different rates.

**Sweet and balanced**: the zone you're actually aiming for.

> **Why this beats guessing:**
> Instead of randomly adjusting grind, ratio and temperature all at once,
> the compass tells you which single lever actually addresses what you're
> tasting, which gets you to a good cup faster and teaches you the
> relationship between adjustment and result along the way.

## Fixing under-extraction

If your coffee tastes sour and thin, try one or more of: grinding finer
to increase surface area, extending your brew time for more contact,
raising water temperature slightly within the standard range, or using a
slightly higher coffee-to-water ratio.

## Fixing over-extraction

If it's bitter and harsh, the fixes run the other direction: coarsen the
grind, shorten the brew time, drop the water temperature slightly, or
reduce your dose a touch.

## A note on origin

Different origins respond differently to the same adjustment. Ethiopian
naturals, prized for delicate fruit character, generally do better with
gentler extraction than that character can survive being pushed hard.
Colombian washed coffees tend to be more forgiving and can handle more
aggressive parameters to bring out their clarity and brightness.

## Why this is worth learning properly

Once you've used the compass a handful of times, you start recognising
the specific taste signatures of under- and over-extraction without
needing to consciously run through the framework, it becomes intuition
built on a real, repeatable method rather than guesswork you never quite
learn from.

## The takeaway

A bad cup of filter coffee almost always has a specific, identifiable
cause. The Coffee Compass turns "this tastes off" into "this tastes
sour, so it needs a finer grind or more time," a genuinely faster and
more educational way to fix your brewing than trial and error.