Filter Stories - Coffee Documentaries
Filter Stories - Coffee Documentaries

Filter Stories - Coffee Documentaries

James Harper

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Episodes

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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!

Recent Episodes

The Speed of Heat: How to roast more coffee, faster!
MAR 24, 2025
The Speed of Heat: How to roast more coffee, faster!
To roast coffee faster, you need to turn up the heat….right?   No!    In this episode, we explore the three powerful methods of heat transfer that revolutionised roasting. We’ll journey from humble beginnings—when roasting three kilos took half an hour—to machines that now roast hundreds of kilos of coffee in the time it takes you to boil a kettle.    But beans roasted at lightning speed look strange, and taste… well, you’ll find out. Join us as we test-drive an industrial tangential roaster where first crack remind me of fireworks crackers.    We also see the whale-sized roaster so massive it’s worth you a Guinness World Record.    We have the technology today to roast coffee faster than ever, so why aren’t we all roasting at recording-breaking speeds?   ---------------   Please spread the word about The Science of Coffee!Leave a 5 star rating on SpotifyFollow me on Instagram and tag me in an Instagram storyWrite a review on Apple Podcasts Discover how I make these Filter Stories episodes by subscribing to my Substack newsletter   Check out the Probat roasters mentioned in this episode:   Emmerich Spherical Roaster - "Pink Hydrant" Large ball roaster - “Sputnik in a pizza oven” G45 early drum roaster - “Old school steam train”  Early tangential roaster Sample tangential roaster - "Shoebox" Neptune 4000, the largest drum roaster in the world! - "The whale"   And there are lots of other specialty roasters from Probat I didn't have time to showcase, including their new hydrogen powered roasters. See them all for yourself!.   Theodor von Gimborn's wikipedia page     Go deeper into the science of roasting   Read Mark Al-Shemmeri’s coffee roasting blog Do a Certificate of Advanced Studies with the Coffee Excellence Centre Explore Barista Hustle's online roasting learning Learn more from Morten Münchow and his coffee roasting courses Read Morten’s paper in collaboration with the University of Copenhagen on Roasting Conditions and Coffee Flavour Follow Filter Stories on Instagram for my infographics Learn more about first crack on my episode Coffee Roasting, Part 1: How heat transforms coffee beans     Season 3 is made possible by these leading coffee organizations:   The Coffee Quest | BWT | TODDY | Algrano | Probat    
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52 MIN
Coffee Roasting: How baby plant food transforms into delicious coffee flavours
MAR 10, 2025
Coffee Roasting: How baby plant food transforms into delicious coffee flavours
A mother coffee plant gifts its baby everything it needs to grow—a green seed packed with food. But when we roast coffee, we hijack that gift and turn it into something else: flavor.   But what is flavor, at a microscopic level? What actually happens inside the bean when heat meets those nutrients?   In this episode, we shrink down to witness the Maillard reaction up close—a wild chain of molecular collisions that transforms baby plant food into aromas we adore.    Grab your popcorn - you’re getting a front row seat at the wildest chemistry show in coffee.    ---------------   Please spread the word about The Science of Coffee!Leave a 5 star rating on SpotifyFollow me on Instagram and tag me in an Instagram storyWrite a review on Apple Podcasts Discover how I make these Filter Stories episodes by subscribing to my Substack newsletter Ethiopian forest sounds curtesy of George Vlad. Hear more nature sounds here.Explore Probat's roasters     Go deeper into the science of roasting   Do a Certificate of Advanced Studies with the Coffee Excellence Centre Grab a copy of Anja Rahn's upcoming book on coffee science through her Instagram Explore Barista Hustle's online roasting learning Learn more from Morten Münchow and his coffee roasting courses Read Morten’s paper in collaboration with the University of Copenhagen on Roasting Conditions and Coffee Flavour Follow Sebastian Opitz on LinkedIn Follow Filter Stories on Instagram for my infographics     Season 3 is made possible by these leading coffee organizations:   The Coffee Quest | BWT | TODDY | Algrano | Probat    
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47 MIN
Fruit juice or creamy almonds? Your guide to controlling cold brew flavors
FEB 16, 2025
Fruit juice or creamy almonds? Your guide to controlling cold brew flavors
When I started making cold brew this last year, I treated it like hot brew filter coffee. But no matter how I adjusted the grind or tweaked the brew time, I hardly got any differences in flavor…   Then it hit me: cold brew isn’t just a slower hot brew—it’s a completely different game with its own rules!   In this episode, I speak with leading coffee researchers who break down the microscopic dance between water and coffee that explains why cold brew plays by its own playbook.   And I bring you in on the brewing secret that can turn your brews from fruit juice to nutty creaminess.    ---------------   Please spread the word about The Science of Coffee!Leave a 5 star rating on SpotifyFollow me on Instagram and tag me in an Instagram storyWrite a review on Apple Podcasts Discover how I make these Filter Stories episodes by subscribing to my Substack newsletterExplore TODDY’s cold brewing kits     Go deeper into the science of cold brew   Do a Certificate of Advanced Studies with the Coffee Excellence Centre Read Jiaxin (Jessie) Liang’s equilibrium extraction SCA 25 article and her published article Discover all of UC Davis' cold brew research through the Coffee Science Foundation Learn how to do a cold brew cupping with Toddy Follow Filter Stories on Instagram for my infographics       Season 3 is made possible by these leading coffee organizations:   The Coffee Quest | BWT | TODDY | Algrano | Probat
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46 MIN
Hot vs Cold: The science behind temperature and taste
FEB 3, 2025
Hot vs Cold: The science behind temperature and taste
For years, I used cold brew as a last resort—the only brew method to tame dark, oily beans that were too bitter for hot water.    Then one day, I took a chance on a Guatemalan Gesha and brewed it cold. The result? A massive explosion of florals I’d never tasted before. That single cup sent opened my eyes into how extraordinary cold brew can be.   In this episode, I speak with world-leading coffee scientists who explain why brewing with cold water tastes so different from chilled hot coffee.    You’ll learn how certain flavors leap into your cup (and how others mysteriously vanish) when you lower the brew temperature.   You’ll also discover there are hidden “cold brew gems” in beans you thought you knew. So before you grab the kettle, consider this: sometimes all you need is cold water.   ---------------   Please spread the word about The Science of Coffee!Leave a 5 star rating on SpotifyFollow me on Instagram and tag me in an Instagram storyWrite a review on Apple Podcasts Discover how I make these Filter Stories episodes by subscribing to my Substack newsletterExplore TODDY’s cold brewing kits     Go deeper into the science of cold brew   Do a Certificate of Advanced Studies with the Coffee Excellence Centre Listen to my episode on Coffee Extraction for insights into how polarity affects flavor extraction Read the UC Davis cold brew vs chilled hot brew study Listen to my episode on 'How to think like a scientist' Learn how to do a cold brew cupping with Toddy Follow Filter Stories on Instagram for my acidity infographic Go deeper into Paul Breslin's work at the Monell Chemical Senses Centre Discover all of UC Davis' cold brew research through the Coffee Science Foundation     Season 3 is made possible by these leading coffee organizations:   The Coffee Quest | BWT | TODDY | Algrano | Probat
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45 MIN