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percolation method

Chemex

A pour-over method using an hourglass-shaped glass vessel and a thick, proprietary paper filter, producing an exceptionally clean, tea-like cup by removing more oils and fine particles than a standard cone filter.

Coffee-to-water ratio
55–65 g per litre (typically 60)
Grind
Medium-coarse.
Water temperature
90-96 celsius (typically 94)°C
Contact time
210-300 seconds (typically 240)
Skill level
intermediate

Descriptive grind labels like this are illustrative starting points, not precise measurements — the same label can mean different particle sizes on different grinders. See the grind size guide for how to dial this in on your own equipment.

Expected flavour profile

Produces an unusually clean, light-bodied, tea-like cup — the thick proprietary filter removes more oils and fine particles than a standard cone filter, trading some body and sweetness for extra clarity and brightness.

Equipment

Common problems

  • Brew runs slowly due to the thick filter
  • Coffee tastes thin if ground too coarse

Grind slightly coarser than V60 to compensate for the thicker filter's added resistance.

Full troubleshooting guides

Taste variables you can control

Derived from CoffeeHQ's own Change the Taste guidance for this method, not a marketing feature list.

  • Grind size
  • Pouring pattern
  • Water temperature
  • Agitation
  • Filter
  • Dose
  • Water amount

Change the taste

Chemex is a pour-over dripper close enough to V60 that the same grind, pour and temperature guidance applies.

Tastes sour

(Chemex)

The brew tastes sour or thin, and often drains through faster than expected — usually under-extraction.

Try the first step below on its own, taste, then move to the next one only if needed.

ChangeTryWhyWatch for
FirstGrind sizeDecrease: a small step finerSlows the drawdown and usually increases extraction.—
Pouring patternCheck / reset: pour more slowly and evenly across the whole bedEven saturation extracts more consistently than fast, off-centre pouring.Very slow pouring can itself stall the brew if the grind is already fine.
Water temperatureIncrease: a few degrees hotterHotter water extracts more quickly, within the method's normal range.—
AgitationIncrease: ensure a full, even bloom before the main poursA poorly saturated bloom leaves parts of the bed under-extracted.—

Check for channelling first (water finding a fast path through the bed) — that can taste sour even with a correct grind, and the fix is even pouring, not a finer grind.

When to reset: Return to your usual grind and pour pattern before making a second change.

Full troubleshooting: Coffee tastes too sourFull troubleshooting: Uneven coffee bed after pour-over brewingRelated toolRelated tool

Want to know why? Extraction, Contact time

Tastes harsh or dry

(Chemex)

The brew tastes bitter or dry, often alongside a slow, stalling drawdown — usually over-extraction.

Try the first step below on its own, taste, then move to the next one only if needed.

ChangeTryWhyWatch for
FirstGrind sizeIncrease: a small step coarserSpeeds up the drawdown and usually reduces extraction.—
AgitationDecrease: pour more gently, avoid stirring the bedLess turbulence reduces the chance of over-extracting fines.—
FilterCheck / reset: check the filter isn't cloggingA slow drain can be a blocked filter or too many fines rather than a grind problem.—
Water temperatureDecrease: a few degrees cooler, especially for darker roastsSlower extraction can soften bitterness.—

When to reset: Check the grinder for excess fines before assuming the recipe alone is the cause.

Full troubleshooting: Coffee tastes too bitterFull troubleshooting: Pour-over brew stalls or drains too slowlyRelated toolRelated tool

Tastes weak

(Chemex)

The brew tastes thin in strength without being clearly sour.

Try the first step below on its own, taste, then move to the next one only if needed.

ChangeTryWhyWatch for
FirstDoseIncrease: add coffee to reach a standard ratioMore coffee for the same water raises strength directly.—
Water amountDecrease: use slightly less total water for the same doseRaises strength without necessarily changing extraction.—
Grind sizeCheck / reset: avoid using grind as the only lever for strengthGrind mainly changes extraction, not strength — dose and ratio are the direct levers.—

When to reset: Adjust dose or ratio via the ratio calculator, then keep grind unchanged until you've re-tasted.

Full troubleshooting: Coffee tastes weak or wateryRelated tool

Want to know why? Strength (intensity), Extraction

Tastes inconsistent

(Chemex)

The cup tastes inconsistent cup to cup, or hollow in the middle of the flavour — often uneven extraction across the coffee bed.

Try the first step below on its own, taste, then move to the next one only if needed.

ChangeTryWhyWatch for
FirstPouring patternCheck / reset: pour in a slow, deliberate spiral covering the whole bedImproves even saturation across the grounds.—
AgitationIncrease: ensure the bloom fully saturates before the first main pourAn incomplete bloom leaves dry pockets that never extract properly.—
Grind sizeCheck / reset: check for a consistent grind, not just the right average sizeA grinder producing a wide mix of fine and coarse particles extracts unevenly regardless of the average setting.—

When to reset: Focus on pouring technique before changing grind, since technique is the more common cause.

Full troubleshooting: Uneven coffee bed after pour-over brewingFull troubleshooting: Grinder produces inconsistent groundsRelated tool
See the full Change the taste guide

Cleaning & maintenance

Rinse the glass vessel after use; discard the filter and grounds.

None beyond routine cleaning.

Roasts and coffees that suit it

Work out your quantities

Tools for planning a brew with this method, and for adjusting one that did not go to plan.

Techniques for this method

The individual skills this method uses, each with its own adjustments and failure modes.

The whole sequence

Each step links to its own page; this is the order they belong in.

Improve your filter coffee

You brew pour-over or drip and want it to be the same good cup twice.

Filter brewing is forgiving enough that every change is legible, which makes it the best place to learn how the variables behave.

  1. A scaleThe cheapest thing that makes a brew repeatable.
  2. The kettleWhen the spout matters, and when it genuinely does not.
  3. Rinsing the filterTen seconds that do three useful things.
  4. BloomingLetting the gas out before it pushes the water away.
  5. Pulse pouringControlling agitation and contact time with the pour itself.
  6. Dialling inRatio for strength, grind for extraction — kept separate.
  7. Ratio calculatorScale a recipe to whatever you are actually brewing.