Cup Engineering

The science

The story of a brew

The physics and chemistry behind a good cup, written for people who brew — and written to be read in order, like a story. It begins with the two numbers that describe every cup, follows the water into the grounds and the bean back to the farm, and ends with you, dialling in tomorrow morning's brew. Each chapter stands alone too, so dip in anywhere.

Every claim is cited, sources are tiered by trust, and where the evidence is thin we say so — that's the deal.

  1. 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.

    5 min read · 10 sources (1957–2021) · reviewed 2026-09-05

  2. 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.

    4 min read · 6 sources (1996–2021) · reviewed 2026-09-05

  3. Chapter 3 · Variables

    Grind Size and Particle Distribution

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

    4 min read · 8 sources (2005–2026) · reviewed 2026-09-05

  4. Chapter 4 · Variables

    Water Chemistry for Coffee

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

    4 min read · 5 sources (2014–2018) · reviewed 2026-09-05

  5. Chapter 5 · Variables

    Temperature, Time and Agitation

    The three extraction levers you use after grind is set — and why they interact.

    4 min read · 8 sources (2015–2021) · reviewed 2026-09-05

  6. Chapter 6 · Variables

    Blooms, Pulse Pours and Pre-infusion

    Most recipes brew in stages — a bloom then several pours, a pre-infusion then full pressure, a steep with a stir. What the evidence actually says about each stage, and how the calculator models them.

    7 min read · 13 sources (2002–2026) · reviewed 2026-09-06

  7. Chapter 7 · Coffee Science

    Roasting: What Heat Does to a Green Bean

    Drying, Maillard reactions, caramelisation, first crack and development — and why roast level dictates how you brew.

    4 min read · 9 sources (1985–2020) · reviewed 2026-09-05

  8. Chapter 8 · Coffee Science

    Processing Methods

    Washed, natural, honey, anaerobic and wet-hulled — what happens between picking a cherry and bagging green coffee, and how it shows up in the cup.

    4 min read · 5 sources (2015–2026) · reviewed 2026-09-05

  9. Chapter 9 · Fundamentals

    Percolation vs Immersion: How Brewers Differ

    Every brewer is a variation on two ideas — water flowing through coffee, or coffee sitting in water. What each one does to extraction.

    5 min read · 7 sources (2005–2026) · reviewed 2026-09-05

  10. Chapter 10 · Coffee Science

    Species, Varieties and Terroir

    Arabica vs Robusta, the family tree of Bourbon and Typica, what altitude and density really do, and why Gesha costs what it costs.

    3 min read · 6 sources (1985–2026) · reviewed 2026-09-05

  11. Chapter 11 · Practice

    Dialling In: A Troubleshooting Guide

    Taste it, name the problem, change one thing. A practical diagnostic flow for any brew method.

    4 min read · 8 sources (1996–2021) · reviewed 2026-09-05

  12. Chapter 12 · Practice

    Freshness, Degassing and Storage

    What happens to roasted coffee over days and weeks, when it peaks, and how to slow the decline.

    3 min read · 7 sources (2014–2021) · reviewed 2026-09-05

  13. Chapter 13 · Practice

    Measuring Your Brew: Scales, Refractometers and Logs

    What to measure, what the instruments actually tell you, and how to turn a refractometer reading into an extraction number.

    4 min read · 5 sources (2015–2024) · reviewed 2026-09-05