Pourover Technique
Sources: The Physics of Filter Coffee by Jonathan Gagné (2020)
Manual pourover (percolation) brewing offers the highest degree of control over filter coffee variables, but that control comes with a consistency requirement: small deviations in technique compound quickly across a brew. This page covers the habits and parameter logic that translate physics understanding into repeatable, high-quality results.
Core Principle: Measure, Don’t Guess
Consistency begins with measurement. Volumetric estimates for dose and water are insufficient — weight is required. A scale (preferably with pour-rate display) and a Coffee Refractometer for TDS are the minimum tools for serious pourover work. Unaided perception drifts over a session in ways that are hard to detect without data.
Water
- Use craft water or known-quality water with total alkalinity 40–70 ppm as CaCO₃ and total hardness 50–150 ppm as CaCO₃. See Brew Water Crafting.
- Shake large custom-water bottles before use; minerals can stratify.
- Tap water composition changes seasonally — monitor and adjust.
- Do not let water boil in the kettle for extended periods before brewing; significant evaporation raises mineral concentrations.
Kettle Temperature
- Light roasts: 99°C (off-boil) — high temperature extracts all compound families efficiently and delivers full sweetness. Near-boiling is recommended for all light-roasted Arabicas.
- Medium roasts: 92–96°C
- Dark roasts: 88–92°C — lower temperature selectively suppresses some of the harsh compounds that concentrate at higher extractions in darker beans. Reduce by ~3°C increments from 99°C until bitterness is acceptable.
Slurry temperature in the cup is approximately 5°C below kettle temperature for most drippers. Plastic drippers retain heat better than ceramic; ceramic better than glass. Preheat all drippers (especially ceramic and glass) immediately before use and always with the same method — delay between preheating and brewing changes starting temperature and therefore AEY.
Grind
- Dial in to a target of coarse sea salt appearance for a standard V60 recipe
- Start coarser than expected when dialing in a new grinder — begin where brews taste sour and thin, then progress finer until flavor peaks. Starting too fine makes diagnosis harder.
- Clean burrs regularly (every few weeks). Dirty burrs widen the particle size distribution and degrade flavor.
- Allow new burr sets to season (~first 1–2 kg of coffee) before expecting a stable dial-in.
- Room temperature affects particle size: warmer beans grind coarser. High-frequency grinding in a short session heats the burrs, shifting the distribution.
See Grind and Coffee Bed Hydraulics.
Coffee Dose and Brew Ratio
| Variable | Recommendation |
|---|---|
| Brew ratio (water:coffee) | 1:16–1:17 for most filter coffee |
| High-soluble coffees (Kenyans) | 1:17.5–1:18 |
| Decaffeinated coffee | 1:15–1:16 |
| Dose for a standard V60 | ~22 g |
Choose a ratio that suits your grinder quality (larger burrs allow higher ratios) and commit to it during dial-in — change ratio only after finding the optimal grind size.
Filter Preparation
- Fold the filter seam flat and press it against the dripper wall — a lifted seam allows water to bypass the coffee bed.
- Prerinse with cold tap water (not hot); the filter should adhere to the dripper wall. Let water drain; do not pour it out (pouring lifts the filter).
- After rinsing, begin brewing promptly — dripper temperature will fall if you wait.
- Note: tabbed vs. tabless Hario V60 paper filters produce measurably different results. Use one type consistently.
Coffee Bed Preparation
Shape the dry coffee bed into a nest (slight hollow in the center) before beginning the bloom. This allows bloom water to contact the bottom of the bed immediately, improving uniform wetting, especially for the lower coffee layers.
- Alternatively: gently shake the dripper left-to-right to flatten the bed, then make the nest with a finger
- Keep the bed shape consistent across brews
Bloom
- Bloom water: 2× coffee dose by weight (e.g. 44 g water for 22 g coffee)
- Duration: 45 seconds for typical specialty roasts; light roasts may benefit from up to 60 seconds due to higher CO₂
- Swirl the dripper gently after the bloom pour to ensure all grounds are wetted
- Bloom purpose: degas CO₂ (prevents gas bubbles from disturbing the bed during brewing), fully hydrate large particles, eliminate dry pockets that cause Channeling
Main Pours
Gagné’s reference V60 method uses bloom + 2 main pours; the Stagg X benefits from 3–5 pours due to its geometry.
- Pour water in a circular motion — avoid always hitting the same spot, which can hollow out the bed
- Maintain water height ~1 cm above the coffee bed for thermal stability
- Pour from consistent height (use a visual reference mark)
- Use a consistent flow rate — monitor by stream diameter or scale with pour-rate display
- Swirl the dripper gently after each pour to reset forming channels and flatten the surface
Detecting and Fixing Problems
| Symptom | Likely Cause | Adjustment |
|---|---|---|
| Sour, thin, empty | Underextraction — grind too coarse | Grind finer |
| Bitter, harsh, astringent | Overextraction or high fines | Grind coarser; check grinder burr condition |
| Fast drawdown, hollow taste | Channeling | More consistent bloom; swirl; level surface |
| Slow/clogging drawdown | Too many fines; bed too deep | Grind coarser; reduce dose; use thicker filter |
| Inconsistent results day-to-day | Temperature drift, water change, grinder heat | Check room temp, water source, grinder seasoning |
| Muted flavors | Low slurry temperature | Switch to plastic dripper; increase kettle temp |
Measure AEY with a Coffee Refractometer to distinguish extraction level from concentration effects. See Coffee Brewing Control Chart.
Measurement Protocol
To calculate AEY accurately:
- Tare and measure beverage weight (B) immediately after drawdown completes
- Sample a small amount in a glass dropper immediately (before evaporation)
- Wait 15 minutes for the sample to reach room temperature
- Zero refractometer with distilled water
- Measure TDS (C); clean prism with alcohol immediately after
- Calculate: EY = (C × B) / D
See Coffee Bed Hydraulics for the more precise formula accounting for retained water.
Changing Coffee or Roaster
Switching from one coffee bag to another — even the same variety, same roast level — can shift drawdown time and AEY. Denser beans generate more fines; different processing (natural vs. washed) changes hydraulic behavior. Do not aim to match AEY exactly across different coffees — dial in fresh for each new lot.
Remove quakers (pale, underdeveloped beans) and black beans before grinding; they introduce extraction noise and can degrade consistency.
Relevance to Kaiserblick
For Kaiserblick’s local distribution to El Salvador coffee shops, this framework is directly transferable as a training resource. High-altitude Salvadoran Arabicas — dense, light-roasted — require near-boiling water, careful bloom, and grinders with large enough burrs to minimize fines. Providing guidance on water quality and technique alongside each lot is part of the quality story Kaiserblick can tell.