Lab notebook · home brewing, measured
The pour-over lab
An independent, measurement-first reference for brewing coffee at home. Every number on this site — ratios, temperatures, grind descriptions, competition recipes — links back to the standard, study or official page it came from.
Good home coffee is mostly a handful of controllable variables: how much coffee, how much water, how fine the grind, how hot the water, and how long the two stay in contact. Professional bodies such as the Specialty Coffee Association (SCA) publish targets for exactly these variables, and university researchers have spent the last few years re-testing them. This lab collects those numbers in one place, explains what each one does in the cup, and gives you simple tools to apply them with nothing more than a kitchen scale and a timer.
Start with the ratio
If you change only one habit, weigh your coffee and water. The SCA's brewing best practices recommend 55 g of coffee per liter of water (±10%) — roughly a 1:18 ratio — and many brewers work anywhere from about 1:15 to 1:18. The coffee-to-water ratio guide explains where those numbers come from (including the 1950s brewing control chart) and includes a calculator that shows its formula.
The lab's core references
Every page in the lab, grouped by section. Each section heading opens its index.
Brew methods 11 pages →
TechniquePour-over: bloom, pulses, drippersV60 vs. Kalita Wave vs. Chemex vs. Melitta-style, compared in one table.GuideHario V60 recipe guideSizes 01/02/03, Hario’s one-pour and staged recipes, two versions of the 4:6 method side by side, pour-rate cues and troubleshooting.GuideKalita Wave guide155 vs 185 sizes and filters, four roaster recipes side by side, flat-bed brewing steps, the UC Davis flat-vs-cone study and troubleshooting.GuideChemex recipe + historyMaker, roaster and SCA recipes compared, grams for 3- to 10-cup brewers, filter folding, and the 1941 patent to MoMA.GuideDrip coffee makers + SCA certificationWhat SCA Standard 310-2021 tests (90–96 °C, 1.15–1.55% strength, even extraction, holding), the SCA list as read, settings and troubleshooting.GuideFrench press guide30 g per 500 ml, coarse grind, a 4-minute steep, a slow plunge — and what studies say about cafestol.GuideCold brew guide1:5 concentrate vs 1:10 ready-to-drink, 8–24 h steeps, and what food-safety research says about storage.GuideAeroPress recipesThe official method and World AeroPress Championship winning recipes in a table.GuideMoka pot guideHow the stovetop pot works at 1–2 bar, and how to avoid a bitter finish.GuideTurkish coffeeExtra-fine grind, cezve and slow heating to a foam, ratios and heating steps from six sources side by side (weighed recipes 1:7.5–1:10), caffeine per small cup, and the 2013 UNESCO listing.GuideSiphon (vacuum) coffeeHow vapor pressure lifts the water and a vacuum pulls the coffee down, a 10-step method, four published recipes side by side (about 1:12–1:17), filters, safety, troubleshooting and a history from 1827.
Ratios & recipes 9 pages →
ToolCoffee-to-water ratio calculatorGrams in, grams out, with the SCA 55 g/L reference and French press, pour-over and moka ratios.ReferenceHow much coffee per cupGrams and level tablespoons per cup, which “cup” your coffeemaker means, and how NCA, SCA and maker rules compare.ToolPour-over ratio + pulse calculatorSCA 55 g/L vs the 1:15–1:17 most recipes use, bloom and pulse weights for any dose, and World Brewers Cup champion ratios 2013–2025.ToolIced pour-over calculatorJapanese-style iced coffee by weight: hot water vs ice (25–50% ice in eight published recipes), the total and hot-water ratios, and a melt check.ReferenceFrench press ratio by press sizeGrams of coffee for 8, 12, 17, 34 and 51 oz presses at 1:12–1:18, what a 4 oz press “cup” means, and a calculator.ToolAeroPress ratio + dilution calculatorFull-strength recipes at about 1:11–1:14 vs concentrate-and-dilute champion recipes, the two-ratio math, a labelled diagram and a calculator.ReferenceMoka pot ratio by pot sizeBialetti’s capacities for 1, 3, 6, 9 and 12 cup pots, basket doses from brew guides, the ≈1:10 they work out to, a labelled cross-section and a calculator.ToolEspresso ratio + yield calculatorDose, yield and shot time explained; ristretto 1:1, normale 1:2, lungo; SCAA, Italian and WBC definitions.ArchiveWorld Brewers Cup champion recipesEvery champion 2011–2026 with coffee and brewer, published doses, water, temperatures and grinds, a ratio chart, how the competition works and where sources disagree.
Brewing variables 6 pages →
ReferenceGrind size chartGrind by brew method, plus how contact time and grind size trade off.ReferenceWater temperature & chemistryThe 200°F ± 5° target, what the UC Davis research found, altitude, hardness and alkalinity.ReferenceDIY coffee water recipesDistilled water plus food-grade Epsom salt and baking soda: SCA hardness and alkalinity targets, published recipes in grams, and the ppm-as-CaCO₃ math.ExplainerCoffee bloom explainedWhy fresh coffee bubbles: CO₂ degassing by roast level and days since roast (ZHAW data), what bloom tests show, and a 2–3× water, 30–45 s method.ReferenceBrewing control chart explainedLockhart’s 1957 TDS-vs-extraction chart, its nine zones, and the new UC Davis sensory and consumer chart.ReferenceCoffee TDS + refractometersWhat a 1.3% reading means in grams and ppm, how a coffee refractometer reads a drop, published accuracy specs, a reading routine and a TDS calculator.
Beans & storage 4 pages →
ReferenceCoffee roast levelsLight, medium and dark: roast names by bean temperature, SCA/Agtron colour numbers and why labels disagree, caffeine by roast, and brewing adjustments.ReferenceCoffee freshnessRoast vs best-by dates, how long whole beans and grounds last by source, oxygen, moisture, heat and light, valve and nitrogen packaging, and the Penn State freezing study.GuideHow to store coffee beansContainers and reclosing methods compared (ZHAW 2022 opened-bag study), what the valve does, cupboard vs fridge vs freezer, step-by-step freezer portioning and a storage checklist.ReferenceCaffeine by brew methodMeasured mg per 100 ml and per serving for drip, espresso, moka, French press, AeroPress, cold brew, instant and decaf, what drives the spread, a range calculator, and FDA/EFSA guidance.
Gear 3 pages →
ExplainerCoffee scales explainedWhat a scale actually measures, flow rate, timers — and a note on the PourX Oura.ExplainerCoffee grinders explainedBurr vs blade, flat vs conical, fines and particle size distribution, with UC Davis and peer-reviewed grinding studies.ReferenceCoffee filters: paper vs metal vs clothWhat each filter lets through, cafestol as four studies measured it and where they disagree, bleached vs unbleached paper, filter sizes, rinsing and the 1908 Melitta filter.
Tools 5 pages →
ToolPrintable coffee ratio chartCups to grams of coffee and water at 1:15–1:18 and 55 g/L, for 8 fl oz and 5 fl oz coffeemaker cups.ToolPour schedule generatorDose and ratio in, timed pour table out: Kasuya’s 4:6 method (Philocoffea and HARIO Europe timings) or bloom plus pulses on Kalita Wave guide intervals, with a brew timer.ToolExtraction yield calculatorEY% from TDS, dose and beverage weight, with the full-immersion formula from UC Davis research and the 18–22% reference box.ToolWater hardness converterppm / mg/L as CaCO₃, grains per gallon, °dH, °fH, °e and mmol/L, with the USGS hardness band and SCA brewing-water ranges.ToolTemperature converter + altitude boiling point°F ↔ °C for brewing targets, and where water boils at your elevation (NWS standard atmosphere + NIST Antoine equation) against the SCA 195–205 °F band.
History & glossary 4 pages →
HistoryBrewing device history: percolator to AeroPressA dated timeline from the 1819 percolator to the 2005 AeroPress, with the patents behind the moka pot, French press, Chemex and V60, and where the records disagree.HistoryCoffee filter history: Melitta Bentz, 1908The 1908 utility model, the 1930s cone and filter bag, museum objects, a dated timeline, where the records disagree, and dates for other brewing devices.ReferenceCoffee brewing glossaryBloom, bypass, channeling, drawdown, extraction yield, fines, slurry, strength and TDS, A–Z with SCA definitions and a labelled pour-over diagram.Domain noteHello: what happened to pourxlab.comA sourced note on PourX, the Taiwanese company whose Oura scale used this domain, and where to start in the lab.
How this lab works
- Measure, then taste. Weights in grams, temperatures in °F and °C, times in minutes and seconds. Volume scoops are mentioned only when a source uses them.
- Sourced, not tested. We do not run taste panels or review products. Figures come from standards bodies (SCA), peer-reviewed research (UC Davis Coffee Center), competition organizers and encyclopedic references, and every page lists them.
- Nothing for sale. No shop, no affiliate links, no ads. Brands appear only where history or a cited recipe requires it.
Why the old name?
This domain previously belonged to PourX, a Taiwanese company whose Oura scale used lights to guide pour-over brewing. Links from older coffee articles still point here, so the coffee scales explainer includes a short, sourced history note on that scale, and the recipes page continues the theme readers expected. The lab itself is a new, unrelated project — see About and Hello.
New to measured brewing? Read in this order: ratio → grind → water → your brewer's guide. Change one variable per brew and write it down — that is the whole lab method.