Why coffee can taste sour and bitter at the same time.

If coffee tastes sour and bitter in the same sip, it is often uneven extraction.

Some parts of the coffee are under extracted (sharp, sour), while other parts are over extracted (bitter, drying). The fix is usually not a new recipe, it is consistency.

What to change first

1. Lock your recipe

• Weigh dose and water.

• Keep the same ratio and time target for a few brews.

2. Make your technique repeatable

• • Espresso: consistent distribution and level tamp.

  • Pour over: consistent pouring pattern and flow.

  • Immersion: consistent stirring and steep time.

3. Then adjust grind in small steps
   Once your process is stable, grind changes become predictable.

Fixes by brew method

Espresso

This is commonly channeling.

• Break up clumps, distribute evenly, tamp level.

• Confirm your basket and dose match.

• If the shot still flips between sharp and harsh, grind adjustments will not be stable until puck prep is stable.

V60 pour over

This is often an uneven bed or inconsistent agitation.

• Keep pours steady and repeatable.

• Reduce aggressive swirling and stirring.

• Make sure the bed looks level at the end.

AeroPress

• Keep steep time stable.

• Keep agitation consistent, or reduce it.

• Then adjust grind in small steps.

Plunger

• Grind coarser if you are getting harshness and sludge.

• Skim crust and floating fines.

• Decant immediately after plunging.

Moka pot

Sour and bitter together can happen when heat is too high and flow is inconsistent.

• Use hot water in the base.

• Keep heat low.

• Stop early, cool the base.

FAQs

Can one coffee be both under and over extracted?
Yes, if extraction is uneven across the bed or puck.

Why does this happen more with espresso?
Espresso is fast and pressurised. Small prep inconsistencies can create channels quickly.

Should I change the ratio to fix this?
Fix consistency first. Ratio changes are hard to judge if technique is unstable.