The Science of Coffee

1) Water For Brewing Coffee

The Science of Coffee

Show Notes

A newer, updated version of this episode is out — listen here instead!

-----

Water really matters when you’re brewing coffee. Different waters can dramatically change how a single coffee will taste.

But what is the right water for the best coffee?

In this episode I will give you the answer, but I will first take you back billions of years to tell you the story of a single mineral and how it's responsible for making our coffees taste lame. Because here’s the thing: water science is chemistry, and chemistry is very complicated and easily forgettable. But with a great story, I’m hoping you’ll remember!

In the second half, I show you why Christopher Hendon’s book Water for Coffee made a big splash in the coffee community, but also why some academic chemists are critical of the book, and how this all manifested in the creation of the Specialty Coffee Association’s Water Quality Handbook.

And, to cap it all off, I offer you some environmentally conscious ways to get hold of good water for coffee, so your coffee brews can finally explode in flavour.

—---

Please spread the word about The Science of Coffee!

Follow me on Instagram and tag me in an Instagram story

Write a review on Apple Podcasts

Leave a 5 star rating on Spotify

Discover this episode’s sponsor BWT’s water filtration products. I use their Penguin Magnesium Mineralised cartridges and cafes can use their BestAqua ROC

Read Marcia Bjornerud’s amazing book, Reading The Rocks

Want more to listen to more documentary podcasts about coffee? Check out Filter Stories

Want to go deeper into water chemistry?

SCA’s Water Quality Handbook

BWT White Paper on the effects of magnesium (German)

How to add magnesium to your soft water out of the tap (scroll to bottom)

Christopher Hendon’s Water for Coffee

Certificate of Advanced Studies at Zurich’s Coffee Excellence Center online course

Read ‘The Craft and Science of Coffee’

Barista Hustle's Water course

James Hoffman's water video

Connect with my very knowledgeable guests:

Samo Smrke - LinkedIn and Instagram

Chahan Yeretzian - Linkedin

Frank Neuhausen - LinkedIn

Marcia Bjornerud - Academic profile

Christopher Hendon - LinkedIn and Instagram

The Science of Coffee is made possible by these leading coffee organisations:

BWT Water and More - https://link.filterstories.org/3EEpuxN

Marco Beverage Systems - https://link.filterstories.org/3T2YDzY

Trabocca - https://link.filterstories.org/3Tjn8bV

Eversys - https://link.filterstories.org/3CBkp6X

Oatly - https://link.filterstories.org/3exvlKS

Fiorenzato - https://link.filterstories.org/3T3nmUQ

Subscribe to my A History of Coffee podcast

Use ProfilePrint to find the coffee your customers loved last year (without a week of cupping!). Use promo code "FILTER" to get 10% off your first year of a Mini Beluga subscription. Click here to discover ProfilePrint's many uses.

What kind of racing car does the Gaggia Classic GT home espresso machine remind you of? Use discount code FS202610 to get 10% off.

Meet the Mazzer Super Jolly g, the iconic grinder that's got even better. Click here to learn about its super fast grinding, bump protection, and 100th-of-a-gram accuracy.

More from The Science of Coffee

Dec 8, 2025

For twenty years, the 2004 cupping form profoundly shaped the specialty coffee world. But on the hillsides of coffee farms, some of the form’s byproducts have been disadvantaging producers. In this episode, we follow two producers whose lives collided with the myth of universal quality. These stories reveal how a single idea of “quality” can close doors for the people with the least power in the supply chain. The new coffee evaluation form, the CVA, is still young, and with any luck it will keep evolving. I hope for a form that can empower even the smallest producers. Please support my work directly at Ko-fi.com/FilterStories Other ways you can help: Leave a 5 star rating on Spotify Follow me on Instagram and tag me in an Instagram story Write a review on Apple Podcasts Discover how I make these Filter Stories episodes by subscribing to my Substack newsletter Go deeper into the story of quality: The original Filter Stories episode about Murray Cooper in Ecuador, Firefly Specialty Coffee Association's new Coffee Value Assessment 2004 cupping form from the Specialty Coffee Association of America SCAA Coffee Cuppers Handbook (4th edition, 2011) Kenneth Liberman's book, "Tasting Coffee: An Inquiry into Objectivity" SCA's video series on the CVA presented by Peter Giuliano Use ProfilePrint to find the coffee your customers loved last year (without a week of cupping!). Use promo code "FILTER" to get 10% off your first year of a Mini Beluga subscription. Click here to discover ProfilePrint's many uses.

Dec 8, 2025

If you ask two specialty professionals what makes a high-quality coffee, you’ll likely get a surprisingly consistent answer: clean, sweet, juicy, bright. To an outsider, they would be forgiven for thinking coffee quality is universally defined. But the truth is more sober. In this episode, we examine how a simple cupping form helped create a universal idea of quality. We then look at the evidence that, in fact, it’s just the personal preferences of a small group of people masquerading as universal quality. Please support my work directly at Ko-fi.com/FilterStories Other ways you can help: Leave a 5 star rating on Spotify Follow me on Instagram and tag me in an Instagram story Write a review on Apple Podcasts Discover how I make these Filter Stories episodes by subscribing to my Substack newsletter Go deeper into the story of quality: 2004 cupping form from the Specialty Coffee Association of America SCAA Coffee Cuppers Handbook (4th edition, 2011) Cup of Excellence cupping form Kenneth Liberman's book, "Tasting Coffee: An Inquiry into Objectivity" SCA's video series on the CVA presented by Peter Giuliano Use ProfilePrint to find the coffee your customers loved last year (without a week of cupping!). Use promo code "FILTER" to get 10% off your first year of a Mini Beluga subscription. Click here to discover ProfilePrint's many uses.

Dec 8, 2025

For the longest time, coffees were dull and bitter. But then a small group of pioneers changed the world. In this episode, we travel back to the 1960s and ’70s to meet the trailblazers who realised coffees could taste distinctive: sweeter, brighter, cleaner. We discover how their personal preferences became a movement, then a form, and eventually a global definition of “quality”. Please support my work directly at Ko-fi.com/FilterStories Other ways you can help: Leave a 5 star rating on Spotify Follow me on Instagram and tag me in an Instagram story Write a review on Apple Podcasts Discover how I make these Filter Stories episodes by subscribing to my Substack newsletter Go deeper into the story of quality: Specialty Coffee Association's new Coffee Value Assessment 2004 cupping form from the Specialty Coffee Association of America SCAA Coffee Cuppers Handbook (4th edition, 2011) Michael Sheridan of CQI discussing the inter-organisational politics behind the Houston Expo announcement on Lee Safar's Map It Forward podcast Use ProfilePrint to find the coffee your customers loved last year (without a week of cupping!). Use promo code "FILTER" to get 10% off your first year of a Mini Beluga subscription. Click here to discover ProfilePrint's many uses.

Jul 28, 2025

For the longest time, the coffee community only cared about water’s impact ruining espresso machine boilers and kettles. But what about water’s impact on coffee flavour? In this episode, I tell the story of how the specialty coffee community came to understand water chemistry: the pioneering work of the computational chemist Christopher Hendon and British roaster Maxwell Colonna-Dashwood, the genesis of the SCA’s Water Quality Handbook, and where we are today understanding the impact of minerals on our water. I strongly recommend listening to the two episodes before this one first: Getting great water for coffee, step-by-step & The two ingredients in water that ruin your coffee, and the ancient story behind them Please spread the word about The Science of Coffee! Leave a 5 star rating on Spotify Follow me on Instagram and tag me in an Instagram story Write a review on Apple Podcasts Discover how I make these Filter Stories episodes by subscribing to my Substack newsletter Want to go deeper into water chemistry? Read the SCA’s Water Quality Handbook BWT White Paper on the effects of magnesium (German) Christopher Hendon’s Instagram where he’ll announce his new version of his book, Water for Coffee Do an online Certificate of Advanced Studies at the Coffee Excellence Centre Season 3 of The Science of Coffee is made possible by these leading coffee organisations: The Coffee Quest | BWT | TODDY | Algrano | Probat Note: this is a reworked version of my 2022 episode Water for Brewing Coffee, including portions of my 2024 episode How to think like a scientist, part 2. Use ProfilePrint to find the coffee your customers loved last year (without a week of cupping!). Use promo code "FILTER" to get 10% off your first year of a Mini Beluga subscription. Click here to discover ProfilePrint's many uses.

Jul 28, 2025

550 million years ago, earth was perfect. We had perfect water for coffee AND we were living in a vegetarian paradise! But then Earth changed—violently. The planet shifted from a peaceful, plant-eating paradise to a darker, more brutal world. And in this new world, the chemistry of water was forever altered. This is the wild story of how earth-shaking forces and the spirits of long-dead critters ruin your coffees today. This story will help you remember the two invisible ingredients in your water that have a huge impact on coffee flavour and your brewing equipment: calcium and hydrogen carbonate. Read Marcia Bjonerud’s amazing book, Reading the Rocks Please spread the word about The Science of Coffee! Leave a 5 star rating on Spotify Follow me on Instagram and tag me in an Instagram story Write a review on Apple Podcasts Discover how I make these Filter Stories episodes by subscribing to my Substack newsletter Season 3 of The Science of Coffee is made possible by these leading coffee organisations: The Coffee Quest | BWT | TODDY | Algrano | Probat Note: this is a reworked version of my 2022 episode Water for Brewing Coffee. Use ProfilePrint to find the coffee your customers loved last year (without a week of cupping!). Use promo code "FILTER" to get 10% off your first year of a Mini Beluga subscription. Click here to discover ProfilePrint's many uses.

See all episodes →