Learn
Extraction science without the wall of jargon.
This learning space turns the brew science research into practical lessons: what changes extraction, how bloom and agitation behave, and where to start when dialing in.
The extraction spectrum
Under-extracted cups skew sour and thin. Over-extracted cups drift bitter and drying. BrewFlow now lets you explore how grind, heat, and brew time move you across that spectrum.
Learn
Brew Physics
Learn the four levers behind bloom, agitation, ratio, and pour strategy.
Open moduleBrew Physics
Every pour-over variable pushes one of four levers.
The research reduces all the noise into four controllable forces: time, temperature, particle size, and agitation. Learn those, and every recipe starts making more sense.
Time
Longer contact time extracts more.
If the brew finishes too quickly, cups taste sour or weak. If it drags, bitterness and astringency start to build.
Temperature
Hotter water dissolves coffee faster.
Raising temperature increases extraction speed. Lowering it preserves acidity but can leave the cup hollow if other variables stay the same.
Particle size
Finer grind means more surface area and more resistance.
Finer grinds raise extraction potential but also slow drawdown and can clog filters with fines.
Agitation
Movement changes how evenly water reaches the bed.
Agitation from pouring, swirling, or pulse additions boosts extraction, but too much drives fines into the filter and stalls flow.
Why recipes differ
CO2 and saturation
Blooming
Use about 2 to 3 times the coffee dose in bloom water for 30 to 45 seconds. That gives trapped CO2 time to escape so the rest of the brew can wet evenly.
Too short: dry pockets and sourness. Too long or too much bloom water: diminishing returns and a cooler bed.
Agitation control
Pour height
A middle-ground pour height around 8 to 10 inches gives useful turbulence without constantly splashing or clogging the filter.
Too low: gentle but can under-mix. Too high: stronger mixing, more turbulence, and more risk of fines migration.
Flow strategy
Continuous vs pulse
Continuous pours keep the slurry stable and even. Pulse pours add controlled bursts of agitation and are often easier to reproduce at home.
Finer grinds usually prefer gentler, more continuous pours. Coarser grinds often pair well with pulse recipes.
Ratio matters differently
Strength vs extraction
Brew ratio mostly changes cup strength, not extraction itself. A thin cup may need less water, not necessarily more extraction.
1:15 to 1:17 is the common baseline. Going too wide tastes watery; going too tight can taste heavy or muddy.
Start Here
Research-backed baseline
Beans
Fresh light to medium washed coffee
Ratio
20g coffee to 300-320g water
Grind
Medium-fine, aiming for a 2:30-3:00 total brew
Water
93C filtered water
Bloom
40-60g bloom for 30-40 seconds, then one gentle swirl
Continuous
Steady pour at roughly 5-7 g/s, finishing all water by 1:45-2:00
Pulse
3 to 4 equal pulses, allowing the slurry to drop before the next addition
Change one variable at a time so you can taste what the adjustment actually did.
Extraction Science
Change the brew variables and watch extraction shift.
This model is intentionally simple: finer grind, hotter water, and longer brew times all push extraction upward.
Roast profile
Suggested water range
94-96C
Grind tendency
Slightly finer
Dense light roasts usually need more heat and a bit more extraction energy to open up sweetness.
Predicted extraction
Balanced extraction
Your settings are close to a sweet spot with enough energy to taste clear, sweet, and complete.
Cup cues
What to change next
You are near a good baseline. Adjust ratio next if you want the cup stronger or lighter without changing extraction much.
Grind Size Guide
Translate grind language into actual grinder settings.
Brew guides often say “medium-fine” and stop there. This guide turns that into a micron range, texture cue, and real grinder starting point, plus the kinds of drippers and brew times each band tends to support.
Open the grinder conversion toolSelected band
Medium-Fine
Table salt
Micron range
550-650 um
Best for
V60, Origami, brighter cups
Starting point
13-18
Use this as a first dial-in point, then move finer for more extraction or coarser if the drawdown stalls.
Fine
450-550 um
8-12
Medium-Fine
550-650 um
13-18
Medium
650-750 um
18-22
Medium-Coarse
750-850 um
22-28
Device Comparison
See how the brewer changes clarity, body, and forgiveness.
Pick up to three brewers to compare side by side. Conical brewers magnify pour pattern and flow changes; flat-bottom brewers soften some of that sensitivity and often feel easier to repeat.
Fast flow
Hario V60
Bright, layered, expressive
Technique feel
Rewards spiral control and consistent pour speed.
Best for
Drinkers who want acidity, aroma, and transparent cups.
Filter style
Thin conical filter
Medium flow
Kalita Wave
Sweet, round, balanced
Technique feel
Flat bed and three holes make it easier to stay even.
Best for
Beginners or anyone wanting consistency without much fuss.
Filter style
Flat-bottom wave filter
Slow flow
Chemex
Tea-like, delicate, very clean
Technique feel
Needs coarser grind and patience because the filter is thick.
Best for
People who like crisp, light cups with minimal sediment.
Filter style
Extra-thick bonded filter