COFFEE | ONE ROAST AT A TIME
Coffee, from living seed to the cup.
A curious home roaster exploring coffee biology, processing, fermentation and roasting — following evidence, recording experience and keeping the questions open.
AI-generated illustration — used because this is an armchair enthusiast’s educational project, not first-hand farm photography.
EXPLORE
Follow the part of coffee that interests you
Understanding Coffee
Fruit, seed, microbes, fermentation, processing, chemistry, species and climate — following coffee backwards from the cup.
Roasting
Real roast records, machine behaviour, practical experiments and what changes when the roaster itself changes.
Videos
Roasts, experiments, coffee learning and project updates from the Coffee | One Roast at a Time channel.
LATEST FROM THE NOTEBOOK
What I’m learning now
Recent notes, experiments and research-led rabbit holes from the project. This section updates automatically as new notes are published.
Coffee Roasting Thermodynamics – A Beginner’s Attempt to Understand What Is Actually Happening
While researching the move from my Gene Café CBR-301 to the Kaleido M2 Pro, I kept coming across the same word: thermodynamics. I knew,…
RoastAid: From Raspberry Pi Recorder to Roast Companion
RoastAid did not start as something I intended to use while roasting. In fact, it really started somewhere else entirely. Before RoastAid there was…
Learning What the Gene Café Sounds Like
When I first started experimenting with audio around the Gene Café CBR-301, the objective seemed fairly obvious. Could I detect first crack more reliably?…
UNDERSTANDING COFFEE
The questions behind the coffee
The educational side of the site follows one connected story: a living coffee seed, the fruit around it, the people and microbes involved in processing it, the chemistry left for the roaster, and ultimately the cup.
Coffee fruit & seed
What a coffee bean actually is, how the living seed is structured and why that matters long before roasting begins.
Processing
Washed, natural, honey and other processing paths — what is removed, what remains and what those labels can and cannot tell us.
Species & varieties
Arabica, Canephora, varieties and hybrids — and the genetic diversity hidden behind familiar coffee names.
Microbes & fermentation
Yeasts, bacteria, changing environments and microbial succession — treating fermentation as an ecosystem rather than a flavour recipe.
THE ROASTING NEXT CHAPTER
From Gene Café to Kaleido M2
The Gene Café has been the foundation of this project. The Kaleido M2 was ordered on 3 September 2026 and is now the next learning platform: more sensors, more control and a much clearer data path through Artisan.
The question is no longer which roaster to buy. It is what actually changes when more of the roast becomes visible — and whether better information leads to better decisions in the cup.
GENE CAFÉ REFERENCE
The practical guide I wish I had when I started.
The Gene Café remains an important part of the project and its evidence archive. The free 53-page CBR-301 Owner’s Field Guide brings together official documentation, photographs, direct observation and lessons from more than 160 real home roasts.
No email gate · Independent of Gene Café and Genesis Co., Ltd.
Useful resources
Coffee Water Calculator
A simple practical calculator for building repeatable brewing water from low-mineral water and measured mineral additions.
Method & Assumptions
How the project separates measurement, observation, interpretation and uncertainty — and why a convincing graph is not automatically a conclusion.
ONE ROAST AT A TIME
Learning in public, without pretending the questions are settled.
Some pages are based on published research. Some are based on recorded roast experience. Some combine the two. The aim is to keep facts, interpretation and open questions visibly separate — and to leave room for the answer to change when the evidence does.