

Filter Stories - Coffee Documentaries
James Harper
Coffee stories with an extra shot of history and science. Filter Stories is a podcast revealing coffee’s hidden microscopic secrets, its powerful past, and how your choice of beans impacts tens of millions of people.
See the behind-the-scenes stories on Instagram @filterstoriespodcast.
If you haven’t already, please subscribe to the show and review us on Apple Podcasts and Spotify!
See the behind-the-scenes stories on Instagram @filterstoriespodcast.
If you haven’t already, please subscribe to the show and review us on Apple Podcasts and Spotify!
Episodes
Mentioned books

Jan 17, 2023 • 43min
5) Latte Foam
When was the last time you picked up a cappuccino with a mountain of foam perched on top? Maybe these are the cappuccinos you make every morning at home.
I personally really, really dislike them! The foam is cold, raspy, and gets in the way of the actual coffee liquid.
How much better would your mornings be if, instead, your cappuccino had that creamy, silky “microfoam” you find in a specialty coffee cafe?
In this episode, I take you deep into the bubbles of latte foam to show you what makes them, what destroys them, and how you can craft mouth-melting lattes.
Along the way I also settle the big debate: what is the actual difference between regular Oatly and Oatly Barista Edition!?
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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
Try Oatly Barista Edition (this episode’s sponsor) for yourself
Go deeper into latte foam science!
Measure your latte foam’s bubble size!
Marvel at tetrakaidecahedra foam for yourself
Check out Steven Abbott’s brilliant science website
Learn how to create microfoam with Lance Hedrick
Study milk science with Barista Hustle’s online courses
Connect with my very knowledgeable guests
Steven Abbott - website
Rituja Upadhyay - LinkedIn
Nidhi Bansal - LinkedIn
Thom Huppertz - LinkedIn
Sofia Eldhe - LinkedIn
Toby Weedon - LinkedIn
The Science of Coffee is made possible by these leading coffee organisations
BWT Water and More
Marco Beverage Systems
Trabocca
Eversys
Oatly
Fiorenzato

Jan 3, 2023 • 43min
4) Espresso Technology
A good espresso is a sublime experience: rich, sweet, and wonderfully caffeinated.
But, who woke up one morning and thought to themselves, ‘I’m going to build a contraption that forces a tiny amount of super hot water with incredible pressure through a bed of very finely ground coffee’?
Well, the fact is, the first “espresso” machine built 150 years ago was awful in almost every way. Worst of all, if you gave that coffee to anybody on the street, nobody would say it’s even an espresso!
But, over the decades, problems begat solutions that begat more problems that culminated in espresso machines like Eversys that produce gorgeous espressos at just the push of a button.
And it’s got me wondering: what is the perfect espresso machine? How far can we go?
But, before clicking play, be warned: this story gets explosive and bloody!
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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
Learn more about how Eversys espresso machines (this episode’s sponsor) produce high quality espressos
Listen to my A History of Coffee podcast series with Prof. Jonathan Morris
Pictures of the espresso machines featured in this episode
Angelo Moriondo (1884, “Big water boiler with gnarly bits”)
La Pavoni Ideale (1905, "Fire hydrant")
Gaggia Tipo Classica (1947, “Lever”)
Faema E61 (1961, “Retro 60s toaster”)
Eversys (2022, “push button”)
Want to go deeper into espresso machine technology?
Coffee Technician Guild’s Educational Courses
Barista Hustle’s The Espresso Machine course
Read Prof. Jonathan Morris’ book ‘Coffee: A Global History’
Do your own coffee museum tour in Italy!
MUMAC (Milan)
Rancilio Officina 1926 (Milan)
Accademia del Caffè Espresso (Florence)
Connect with my very knowledgeable guests
Jonathan Morris - Instagram
Hylan Joseph - LinkedIn
Giorgio Rancilio - LinkedIn
Anna Cento - LinkedIn
Carlos Gonzàlez - LinkedIn
Silvia Bartoloni - LinkedIn
Jonathan Besse - LinkedIn
The Science of Coffee is made possible by these leading coffee organisations
BWT Water and More
Marco Beverage Systems
Trabocca
Eversys
Oatly
Fiorenzato

Nov 22, 2022 • 1h 3min
3) Plant Genetics
How can you make better coffee at home? Well, an easy way is to buy higher quality beans.
But, I’m concerned this is going to get harder and harder for you in the future.
Climate change is making coffee taste worse while also pushing farmers into financial hardship.
In this episode we explore how genetic development can produce a coffee tree that might save the day. Is there a wild coffee tree happily growing in the forests somewhere that could be our silver bullet? What about if we mix existing documented species together?
But, the big problem is that genetic research is slow, and farmers can’t wait around. So, in the second half, we learn how coffee farmers in Kenya are trying to fix the problem right now.
And I’m actually tentatively hopeful the beans you brew in the morning are not going to get worse. But, it all depends on you, me and the coffee industry making a couple of changes right now.
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Please spread the word about The Science of Coffee!
Follow me on Instagram and tag me in an Instagram story - https://bit.ly/2Mlkk0O
Write a review on Apple Podcasts - https://apple.co/3sf87MV
Leave a 5 star rating on Spotify - https://spoti.fi/3yHkjcV
Learn more about how Trabocca, this episode’s sponsor, works with coffee farmers: https://bit.ly/3Tjn8bV
Support the work of World Coffee Research: https://bit.ly/3VtyoV6
Become a member of Kew Gardens: https://bit.ly/3yFZ8b0
Find some of Alvans Mutero’s (https://bit.ly/3T0NHTy) and Thiriku’s (https://bit.ly/3CCxHQJ) coffee to taste for yourself
Learn more about cloning coffee plants on my other podcast, Adventures in Coffee - https://bit.ly/3EFBmzG
Want to listen to more documentary podcasts about coffee? Check out Filter Stories - https://bit.ly/3zb5vnO
Connect with my very knowledgeable guests:
Sarada Krishnan - LinkedIn (https://bit.ly/3rW9dwB) and Research Gate (https://bit.ly/3VvzDTq)
Aaron Davis - Kew Gardens (https://bit.ly/3CAicZg)
Hanna Neuschwander - LinkedIn (https://bit.ly/3MvW2Mi)
Bernard Gichimu - LinkedIn (https://bit.ly/3VrOIFJ)
Learn more about the coffee varieties discussed on this episode:
SL 28 - https://bit.ly/3MvNIw6
SL 34 - https://bit.ly/3rTX2QX
Ruiru 11 - https://bit.ly/3CXmDPf
Batian - https://bit.ly/3EEls8M
The Science of Coffee is made possible by these leading coffee organisations:
BWT Water and More - https://bit.ly/3EEpuxN
Marco Beverage Systems - https://bit.ly/3T2YDzY
Trabocca - https://bit.ly/3Tjn8bV
Eversys - https://bit.ly/3CBkp6X
Oatly - https://bit.ly/3exvlKS
Fiorenzato - https://bit.ly/3T3nmUQ

Nov 8, 2022 • 53min
2) Coffee Extraction
How you brew your coffee dramatically affects what you taste. And I do mean dramatic! Brewing up the same bag of coffee beans can taste like a slice of heaven, or a slap in the face.
So, what exactly is happening at a microscopic level when water swirls through coffee grinds? Why does boiling water extract certain flavours, while letting the kettle cool for five minutes make it taste markedly different?
In this episode, we dive deep into the academic research conducted at the UC Davis Coffee Center so you can choose your flavour adventure: Do you like your coffees when they’re a sour bomb? A floral caress on the lips? A smokey drag on a pipe? Or a treacle of sweet syrup?
We also explore why it can be so difficult getting the same flavours from the same beans consistently. And finally, I equip you with tools so you can begin finding your perfect brew.
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Please spread the word about The Science of Coffee!
Follow me on Instagram and tag me in an Instagram story - https://bit.ly/2Mlkk0O
Write a review on Apple Podcasts - https://apple.co/3sf87MV
Leave a 5 star rating on Spotify - https://spoti.fi/3yHkjcV
Explore this episode’s sponsor Marco Beverage Systems SP 9 brewer and how it delivers consistent brews in the cafe (https://bit.ly/3Tgh18r)
Listen to the Adventures in Coffee episode about making dramatically different brews using the Aeropress: https://bit.ly/3TghsQ7
Want more to listen to more documentary podcasts about coffee? Check out Filter Stories - https://bit.ly/3zb5vnO
Want to go deeper into coffee extraction?
Mackenzie Batali’s fractionation research - https://bit.ly/3CFnvH0
UC Davis’ brewing control chart research - https://bit.ly/3CLoiGz
Take courses on coffee brewing with the Specialty Coffee Association - https://bit.ly/3EQFoVV
Study at the UC Davis Coffee - https://bit.ly/3TwSgod
Read ‘The Craft and Science of Coffee’ - https://bit.ly/3zb7bN8
Connect with my very knowledgeable guests:
Samo Smrke - LinkedIn (https://bit.ly/3EKrjtg) and Instagram (https://bit.ly/3IdrfRz)
Bill Ristenpart - Academic profile (https://faculty.engineering.ucdavis.edu/ristenpart/)
Mackenzie Batali - LinkedIn (https://bit.ly/3s7VRxr)
Peter Giuliano - LinkedIn (https://bit.ly/3yT66tv)
Danny Pang - LinkedIn (https://bit.ly/3Sd9mqq)
David Walsh - LinkedIn (https://bit.ly/3VEH7Uo)
The Science of Coffee is made possible by these leading coffee organisations:
BWT Water and More - https://bit.ly/3EEpuxN
Marco Beverage Systems - https://bit.ly/3T2YDzY
Trabocca - https://bit.ly/3Tjn8bV
Eversys - https://bit.ly/3CBkp6X
Oatly - https://bit.ly/3exvlKS
Fiorenzato - https://bit.ly/3T3nmUQ

Oct 25, 2022 • 1h 2min
1) Water For Brewing Coffee
A newer, updated version of this episode is out — listen here instead!
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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.
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Please spread the word about The Science of Coffee!
Follow me on Instagram and tag me in an Instagram story - https://bit.ly/2Mlkk0O
Write a review on Apple Podcasts - https://apple.co/3sf87MV
Leave a 5 star rating on Spotify - https://spoti.fi/3yHkjcV
Discover this episode’s sponsor BWT’s water filtration products. I use their Penguin cartridges (http://bit.ly/3Xiuq2a) and cafes can use their BestAqua ROC (https://bit.ly/3EPLIx9)
Read Marcia Bjornerud’s amazing book, Reading The Rocks: https://bit.ly/3EQIYj4
Want more to listen to more documentary podcasts about coffee? Check out Filter Stories - https://bit.ly/3zb5vnO
Want to go deeper into water chemistry?
SCA’s Water Quality Handbook: https://bit.ly/3TyWM5X
BWT White Paper on the effects of magnesium (German): https://bit.ly/3TqOFbq
How to add magnesium to your soft water out of the tap (scroll to bottom): https://bit.ly/3s5WYOm
Christopher Hendon’s Water for Coffee: https://amzn.to/3Tbo3LS
Certificate of Advanced Studies at Zurich’s Coffee Excellence Center online course: http://bit.ly/3xlIOel
Read ‘The Craft and Science of Coffee’: https://bit.ly/3zb7bN8
Barista Hustle's Water course - https://bit.ly/3z8zSKA
James Hoffman's water video - https://bit.ly/3Duxn8f
Connect with my very knowledgeable guests:
Samo Smrke - LinkedIn (https://bit.ly/3EKrjtg) and Instagram (https://bit.ly/3IdrfRz)
Chahan Yeretzian - Linkedin (https://bit.ly/3S4emO1)
Frank Neuhausen - LinkedIn (https://bit.ly/3gg4Fie)
Marcia Bjornerud - Academic profile (https://bit.ly/3eCYuEi)
Christopher Hendon - LinkedIn (https://bit.ly/3EXULMe) and Instagram (https://bit.ly/3eAUuo3)
The Science of Coffee is made possible by these leading coffee organisations:
BWT Water and More - https://bit.ly/3EEpuxN
Marco Beverage Systems - https://bit.ly/3T2YDzY
Trabocca - https://bit.ly/3Tjn8bV
Eversys - https://bit.ly/3CBkp6X
Oatly - https://bit.ly/3exvlKS
Fiorenzato - https://bit.ly/3T3nmUQ

Oct 18, 2022 • 4min
Introducing: The Science of Coffee
The Science of Coffee is a journey into coffee's hidden microscopic secrets to help you make even better coffee at home.
Across six episodes, documentary maker and coffee professional James Harper takes you deep into the world of water for coffee, coffee extraction, plant genetics, espresso technology, latte foam and sonic seasoning.
Subscribe to The Science of Coffee here: https://bit.ly/3TdDnHO
The Science of Coffee is a spin-off series from James Harper's documentary podcast Filter Stories.
Follow James on Instagram: https://bit.ly/2Mlkk0O
Listen to Filter Stories: https://bit.ly/3zb5vnO
The Science of Coffee is made possible by these leading coffee organisations:
BWT Water and More
Marco Beverage Systems
Trabocca
Eversys
Oatly
Fiorenzato

Feb 15, 2022 • 45min
Coffee’s Ticking Time Bomb
Sri Lankan coffee has delicious notes of chocolate and caramel. But it’s basically impossible to find, and we’re going to bet you’ve never drank it.
But that's really odd, because Sri Lanka has the perfect climate to grow coffee, and was once one of the biggest coffee growing countries in the world.
But Sri Lanka was the victim of an ecological ticking time bomb. And this bomb is still ticking, and is going to explode again.
In this special episode of Adventures in Coffee, producer James Harper takes co-hosts Scott and Jools on an adventure back in time, across Ethiopia, Yemen, Sri Lanka to trace the origins of this ticking bomb, and what it’s going to take to defuse it.
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Subscribe to Adventures in Coffee here: https://bit.ly/300V4jS
Sign up for the 2022 Barista League's High Density (free!) conference here: https://bit.ly/3BjAI78
Read Stuart McCook’s excellent book, Coffee Is Not Forever: https://bit.ly/3320rob
And follow his Instagram: https://bit.ly/3sJ2OVI
Follow Hansa Coffee on Instagram: https://bit.ly/3sOyLfr
Listen to James’ stories about El Salvador here: https://spoti.fi/3Lcnuhg
Help other people find the show by leaving a rating on Spotify: https://spoti.fi/3JYduHY
Help others find the show by creating a screengrab of this episode on your podcast player and sharing it on your Instagram stories. Tag us and we’ll reshare it!
Scott Bentley / Caffeine Magazine: https://bit.ly/3oijQ91
Jools Walker / Lady Velo: http://bit.ly/39VRGew
James Harper / Filter Stories: https://bit.ly/2Mlkk0O
A massive thanks to Lawrence Goldberg of Hansa Coffee, Ajantha Palihawadana, Professor Stuart McCook and Harm van Oudenhoven.

Jun 15, 2021 • 33min
Is really expensive coffee really worth it?
Would you ever pay £75 for 100g of coffee beans?
Today I'm sharing the most popular episode from Adventures in Coffee, a sister podcast to Filter Stories that I co-created.
I'd love to know what you thought of these Adventures in Coffee episodes so we can make an even better show for series 2. Just drop your thoughts in this 5 minute survey here: http://bit.ly/AIC_Survey
You can listen to more episodes from Adventures in Coffee here: https://bit.ly/300V4jS

May 27, 2021 • 25min
Coffee Cycle Saturdays
Today I'm sharing the story of a coffee drinker, Jools Walker, and how coffee helped her complete an inner journey.
Listen to more episodes from Adventures in Coffee here: https://bit.ly/300V4jS
Read Jool's book, Back In The Frame: https://amzn.to/2NTbb0r
Piano music written and performed by James Harper.

May 13, 2021 • 47min
6) The Future of Coffee?
Do you grind your beans fresh before brewing your coffee? If so, you are helping overturn a race-to–the-bottom with deep roots in colonial extraction that today is leaving millions of coffee farmers impoverished.
Or, at least, that’s what many specialty coffee companies would like you to believe. The truth is a lot less rosy.
In this final episode of A History of Coffee, Jonathan and James explore where the specialty coffee movement came from, whether it will succeed in arresting coffee’s race-to-the-bottom, and look into the future to understand what might be the future of coffee.
A History of Coffee is a collaboration between James Harper of the Filter Stories - Coffee Documentaries podcast and Jonathan Morris, Professor of History and author of ‘Coffee: A Global History’.
Visit Jonathan’s Instagram (https://bit.ly/37eMS3F) and Twitter (https://bit.ly/3jNr9ou)
& James’ Filter Stories Instagram (https://bit.ly/2Mlkk0O) and Twitter (https://bit.ly/3baTsJk)
Help other people find the show by leaving a review on...
Apple Podcasts: http://apple.co/3jY42aJ
Castbox: http://bit.ly/38sXdcH
Read Jonathan’s book, ‘Coffee: A Global History’ here: https://amzn.to/3dihAfU
Listen to the bonus episode on the ‘A History of Coffee’ podcast channel: http://bit.ly/2NArChO
Music featured in this episode:
La Traviata, Brindisi (Verdi) by MIT Symphony Orchestra: https://bit.ly/3eGUsIf
Infant Holy, Infant Lowly by Ann Alee: https://bit.ly/2SKlaY6