Cup Engineering

An open lab for home coffee science

Understand the cup. Then design the next one.

Cup Engineering is where coffee knowledge goes to work: read the research, predict your brew before you pour, log what actually happened — and your data joins everyone's, making the models and the knowledge sharper. Sources cited. Uncertainty shown.

Predict your next brewRead the story of a brew
157 data points collected10 recipes0 logged brews
Brewing control chartlive model
ideal1:131:151:171:19141618202224260.81.01.21.41.6Extraction yield (%)TDS (%)

The method

One loop, better coffee every pass

01

Learn

The wiki tells the story of a brew in twelve chapters — extraction, ratios, grind, water, heat — every claim cited, every uncertainty admitted.

02

Predict

Set dose, ratio, grind, temperature and time. The calculator predicts TDS, extraction yield and where the cup lands before you pour.

03

Brew

Community recipes matched to the beans in the library, with concrete adjustments when a pairing isn't perfect.

04

Log

Record the real brew — TDS, rating, notes. Measured vs predicted is where your grinder and water start talking.

05

Analyze

Every logged brew joins everyone's on the open dashboard, and the accumulating data is what will calibrate the model. The loop closes, one cup at a time.

The bench

Tools on the bench

Flagship

Brew calculator

Dose, ratio, grind, temperature and time in — predicted TDS, extraction yield and a position on the brewing control chart out. Enter a refractometer reading to see how your gear bends the model.

Pour-overEspressoAeroPressFrench pressCold brew

The lab notebook

Every calculator run, save and logged brew is an anonymous data point. Watch the lab learn in real time.

157
events
64
sessions

Recipe library

Browse, save and submit recipes for every brewer — each tagged with the roast and process it was designed for.

Bean matcher

Every bean scored against every recipe, with concrete adjustments for the mismatch — grind finer, run hotter, shorten the pour.

Science wiki

The fundamentals, written for people who brew — with interactive models and a source for every claim.

This week

Latest from the scan

All updates →

Start here

The story of a brew

All chapters →
Chapter 1 · Fundamentals

Extraction, TDS and the Brewing Control Chart

The two numbers that describe every cup of coffee — how much you dissolved, and how concentrated it is — and how they relate.

Chapter 2 · Fundamentals

Brew Ratios

Why 1:16 became the filter default, what changes as you move away from it, and why espresso and cold brew use completely different numbers.

Chapter 3 · Variables

Grind Size and Particle Distribution

Surface area is what water actually sees. How grind size, fines and grinder design shape extraction.

Chapter 4 · Variables

Water Chemistry for Coffee

Coffee is 98 % water. Hardness, alkalinity and how to build a brewing water that flatters extraction.

From the library

Featured recipes, fresh beans

Pour Over (V60 / Kalita)

Hoffmann-style Ultimate V60

30 g · 1:16.7 · 95 °C

French Press

No-Plunge French Press

30 g · 1:16.7 · 94 °C

Espresso

Modern 1:2 Espresso

18 g · 1:2 · 93 °C

Brazil Cerrado Natural

natural · medium-dark

hazelnut, dark chocolate, brown sugar, heavy body

Kibingo Burundi 2026

washed · light

ginger peach puree, honeycrisp apple, panela, lemongrass, dried tropical fruit

Colombia Anaerobic Natural

anaerobic · medium-light

tropical, funky, pineapple, rum

Colombia Huila Pitalito

washed · medium

caramel, red apple, milk chocolate, balanced

Why this exists

Great coffee should be knowable, not folklore.

Cup Engineering turns coffee science into instruments you can brew with — and every logged brew makes them sharper.

Read the mission and the four commitments →