Filter Stories - Coffee Documentaries

James Harper
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Feb 16, 2025 • 47min

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 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 Explore 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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Feb 3, 2025 • 45min

Hot vs Cold: The science behind temperature and taste

Discover the surprising world of cold brew as scientists reveal why it offers a unique flavor profile compared to traditional hot brewing. Learn how temperature can enhance certain beans, bringing out hidden floral notes you never thought possible. The discussion unfolds fascinating insights into flavor extraction, making you rethink your brewing choices. Before you reach for the kettle, consider the refreshing possibilities of cold water!
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Jan 27, 2025 • 2min

Introducing: Season 3 of The Science of Coffee

We’re back with another series of The Science of Coffee—and this time we’re diving even deeper into coffee’s hidden microscopic secrets!   Over the past year, narrative audio producer and coffee professional James Harper has scoured academic journals, ventured deep into coffee farms, and conducted bold tasting experiments.   Now, he’s weaving those discoveries into captivating audio stories that reveal why coffee tastes the way it does—and how we can make it taste even better.   In this new series, you’ll learn about cold brew extraction science, explore innovations in roasting, and follow the shifting business models that shape farmers’ livelihoods. You’ll also take a journey through commodity vs. specialty supply chains and examine the historical, sociological, and philosophical perspectives that define what “specialty coffee” truly means.   Press the “Subscribe” button so you don’t miss an episode! https://bit.ly/3TdDnHO   For more coffee science and behind-the-scenes content, follow James on Instagram @filterstoriespodcast. https://bit.ly/2Mlkk0O   The Science of Coffee is a spin-off series from James Harper’s documentary podcast, Filter Stories.  https://bit.ly/3ajoT5e   Season 3 is made possible by these leading coffee organizations:   The Coffee Quest | BWT | TODDY | Algrano | Probat
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May 6, 2024 • 47min

Freshness and Grinding, Part 2: How grinders work deep inside

Dive into the fascinating world of coffee grinding technology. Discover how tiny changes in grind size can dramatically affect flavor and extraction. Explore the balance between efficiency and craft in coffee preparation, as café owners navigate advanced machines versus traditional methods. Uncover the intricate mechanics of different grinder designs and their unique impact on taste. From particle distribution to the science behind coffee fines, this discussion reveals how every detail contributes to your perfect cup.
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Apr 22, 2024 • 50min

Freshness and Grinding, Part 1: Protecting your coffee’s flavours

For your coffee to taste its best, it’s crucial you buy fresh roasts and grind fresh.… .….Or maybe not.  When I began creating this episode, I was convinced that ‘fresh is best’. But, after delving into the science of coffee freshness, I don’t believe that anymore.  This episode goes deep into how diffusion and oxidation changes a coffee’s flavours. You’ll learn what it takes to store your coffee grounds unbelievably well. So well, that if you do it right, you will struggle to taste the difference between two month old coffee compared to those same beans freshly ground! But here’s the weirdest thing: Maybe, just maybe, you will prefer old coffee more than the fresh stuff. ---------- Please spread the word about The Science of Coffee! Discover how I make these Filter Stories episodes by subscribing to my Substack newsletter.  Leave a 5 star rating on Spotify Follow me on Instagram and tag me in an Instagram story Write a review on Apple Podcasts Explore Mahlkönig’s range of world leading grinders, trusted by baristas globally. Dive deeper into the science of coffee freshness Do a Certificate of Advanced Studies with the Coffee Excellence Centre Pick up a copy of the SCA’s Coffee Freshness Handbook Connect with my very knowledgeable guests Samo Smrke - Instagram 19 Grams Coffee Roasters in Berlin - Instagram Arnaldo Rodrigues - LinkedIn The Science of Coffee is made possible by these leading coffee organisations: BWT Water and More Marco Beverage Systems ROEST Sustainable Harvest Mahlkönig The Science of Coffee is a spin-off series from James Harper's documentary podcast Filter Stories
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Apr 8, 2024 • 55min

What Is Good Science? Part 2: How to think like a scientist

In the last episode, I discovered that rinsing my Chemex filter papers was a waste of time! As a result I’ve managed to claw back over seven days of my life left on earth.  But why stop there?  The coffee industry is full of elaborate ways of brewing and savouring coffee: fancy drippers, cold metal balls, “slurp-able” cupping spoons. These are very fun, but how many of them actually affect the flavour of our coffee? I fear elaborate coffee gear is wasting our time and money. They're distracting us from the existential crises in coffee that actually require all our attention now. For example, the issue of farmers who grow delicious coffees quitting the business because it’s just getting too hard.  But to figure out whether a popular new coffee tool was actually waste of time or not, I needed to think like a scientist.  This episode is the journey I went on to rewire my brain: I had to learn what good evidence looks like, what to do if I can’t find good evidence, and why it’s important to focus mostly on experimental results while resisting the allure of a compelling theory.  Please spread the word about The Science of Coffee! Discover how I make these Filter Stories episodes by subscribing to my Substack newsletter.  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 this episode’s sponsor BWT’s water filtration products. I use their Penguin magnesium filter cartridges and cafes can use their BestAqua ROC Dive deeper into the science of slurping, water and Signal Detection Theory Do a Certificate of Advanced Studies with the Coffee Excellence Centre Read Georgiana’s paper on soup slurping Learn more about Signal Detection Theory Explore BWT White Paper on the effects of magnesium (German) Browse Christopher Hendon’s book Water for Coffee  Take Barista Hustle's Water course  Watch James Hoffman's water video Connect with my very knowledgeable guests Morten Munchow - Coffee Mind website Jeremy Nelson - LinkedIn Samo Smrke - Instagram Georgiana Juravle - Google Scholar Young Baek - Instagram Frank Neuhausen - LinkedIn Sergio Barbarisi - LinkedIn Alessandro Genovese - LinkedIn The Science of Coffee is made possible by these leading coffee organisations: BWT Water and More Marco Beverage Systems ROEST Sustainable Harvest Mahlkönig The Science of Coffee is a spin-off series from James Harper's documentary podcast Filter Stories
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Mar 25, 2024 • 46min

What Is Good Science? Part 1: How to brew coffee like a scientist

Should you rinse your filter paper before making a filter coffee? Almost everybody in coffee internet says you should.  But what if most of coffee internet was wrong? In this episode, I show you how I try to answer this question like a professional sensory scientist would.  It’s hard. It’s frustrating. But ultimately, it’s worth it because I end up saving seven days of my life left on earth! Please spread the word about The Science of Coffee! Discover how I make these Filter Stories episodes by subscribing to my Substack newsletter Leave a 5 star rating on Spotify Follow me on Instagram and tag me in an Instagram story Write a review on Apple Podcasts Bring out vibrancy in your coffee with BWT’s magnesium water filters for the home and cafe Dive deeper into sensory science methodologies Take Becky Bleibaum's free introductory sensory science course!  Set up a triangulation yourself with DragonflySci’s worksheets Understand Rose Marie Pangborn’s three step process better with Morten Münchow (“Pangborn’s Razor”) Do a Certificate of Advanced Studies with the Coffee Excellence Centre Connect with my very knowledgeable guests Morten Munchow - Coffee Mind website Becky Bleibaum - LinkedIn Samo Smrke - Instagram Sophie Vo - LinkedIn The Science of Coffee is made possible by these leading coffee organisations: BWT Water and More Marco Beverage Systems ROEST Sustainable Harvest Mahlkönig The Science of Coffee is a spin-off series from James Harper's documentary podcast Filter Stories
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Mar 13, 2024 • 41min

Organic Coffee, Part 2: Why don’t we see more organic coffee farms?

Farming coffee organically is amazing because soils are more alive, birds and insects are more plentiful, farmers avoid getting sick with agrochemicals. But, if it’s so great, why is less than 10% of the world’s coffee grown organically? The fact is, going organic is hard. Much harder than growing coffee conventionally. In this episode I show you the story of one of Central America’s most successful organic coffee cooperatives, RAOS, and the four big hurdles that stood in the way of their early founders who all dreamed of converting their farms to organic. This story changed my understanding of farming and is now the reason I choose organic specialty coffee whenever I can. Please spread the word about The Science of Coffee! Discover how I make these Filter Stories episodes by subscribing to my Substack newsletter Follow me on Instagram and tag me in an Instagram story Write a review on Apple Podcasts Leave a 5 star rating on Spotify Dive deeper into organic coffee Learn more about Sustainable Harvest’s Most Valuable Producer programme, their cupping app Tastify, and explore their range of certified organic and Fairtrade coffees Explore RAOS (Cooperativa Regional Mixta de Agricultores Organicos de la Sierra)'s story for yourself Are you a coffee farmer? Get in touch with Lalo Perez Varaona Connect with my very knowledgeable guests Lalo Perez Varaona - LinkedIn Jorge Cuevas - LinkedIn Andrea Futterer - GEPA website Osman Contreras - LinkedIn Roberto Rene Gonzales - Farm website The Science of Coffee is made possible by these leading coffee organisations BWT Water and More Marco Beverage Systems ROEST Sustainable Harvest Mahlkönig The Science of Coffee is a spin-off series from James Harper's documentary podcast Filter Stories
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Feb 26, 2024 • 39min

Organic Coffee, Part 1: The magic of soil

The world’s farming soils are deteriorating quickly. Conventional coffee farming where plants are grown using agrochemicals allowed farmers to reap huge harvests these last 70 years. But these agrochemicals have been at the expense of soil health. I travel to Honduras to explore a potential solution: organic coffee farming. Come with me as I show you the organic farming tricks of Don Rufino, one of the region’s leading organic farmers. He nurtures the soil around his coffee trees using mountain microorganisms, a huge diversity of shade trees, attentive tree pruning, and very funky batches of homemade bug spray. The results speak for themselves: when I pick up a handful of his soil, it is moist, dense and writhing with life. Could these cultivation techniques be the answer to the coffee world’s declining soil health? Please spread the word about The Science of Coffee! Discover how I make these Filter Stories episodes by subscribing to my Substack newsletter! Follow me on Instagram and tag me in an Instagram story Write a review on Apple Podcasts Leave a 5 star rating on Spotify Dive deeper into organic coffee Explore Sustainable Harvest’s range of certified organic and Fairtrade coffees Are you a coffee farmer? Get in touch with Lalo Perez Varaona Check out Don Rufino’s organic cooperative, RAOS Connect with my very knowledgeable guests Lalo Perez Varaona - LinkedIn Tommie Hooft van Huysduynen - LinkedIn Alison Streaker - LinkedIn The Science of Coffee is made possible by these leading coffee organisations BWT Water and More Marco Beverage Systems ROEST Sustainable Harvest Mahlkönig The Science of Coffee is a spin-off series from James Harper's documentary podcast Filter Stories
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Feb 12, 2024 • 46min

Coffee Roasting, Part 2: Roasting made easy

Roasting coffee can be maddening. Just 4° Celsius is enough to make the same green beans taste distinctly different! And there are so many things roasters can play around with: temperature, time, fan speed, drum speed, types of probes…the list goes on and on. So, if you want to start roasting yourself, where do you start!? In the first half of this episode, I interview one of the world's leading roasting teachers who takes me through his published scientific research to give a clear answer. It’s as simple as 80%, 15% and 5%. And then, in the second half, I show you why roasting coffee consistently batch-after-batch is so difficult. But these problems are finally being solved with smart technologies. I visited the ROEST engineering team in Oslo and cracked open their innovative prototype P3000 roaster to show you the technology that allows anybody to roast coffee consistently and fully automatically. I am so impressed with these innovations, I believe they’re going to change the coffee industry. 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 Dive deeper into the science of roasting Explore ROEST’s innovative products for the coffee industry. 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 Connect with my very knowledgeable guests Sverre Simonsen - LinkedIn Callum Gilmour - LinkedIn Veronica Balduc - LinkedIn Morten Münchow - Coffee Mind website Scott Rao - Instagram The Science of Coffee is made possible by these leading coffee organisations BWT Water and More Marco Beverage Systems ROEST Sustainable Harvest Mahlkönig The Science of Coffee is a spin-off series from James Harper's documentary podcast Filter Stories

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