• Fruit juice or creamy almonds? Your guide to controlling cold brew flavors
    Feb 16 2025

    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.

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    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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    47 mins
  • Hot vs Cold: The science behind temperature and taste
    Feb 3 2025

    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 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

    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 mins
  • Introducing: Season 3 of The Science of Coffee
    Jan 27 2025

    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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    2 mins
  • Freshness and Grinding, Part 2: How grinders work deep inside
    May 6 2024

    Deep inside your coffee grinder, tiny changes can have massive consequences. This episode takes you deep inside Mahlkönig’s grinders to show you how coffee is ground and the importance of particle sizes on flavour. If you’re a home coffee lover, you could easily spend thousands of dollars on your coffee grinder. But after diving deep into the R&D of grinder manufacturing, I learned that after a certain point spending more probably won’t produce a better tasting cup of coffee for you! --------- Please spread the word about The Science of Coffee! Discover how I make these Filter Stories episodes by subscribing to my Substack newsletter. Write a review on Apple Podcasts Follow me on Instagram and tag me in an Instagram story Leave a 5 star rating on Spotify Explore Mahlkönig’s range of world leading grinders, trusted by baristas globally. Go deeper into the world of grinding Take Barista Hustle’s Advanced Espresso course Learn from Lance Hedrick where the sweet spot is for buying a coffee grinder Get super nerdy with Jonathan Gagne’s writings on grinding Read up on Samo Smrke’s work on coffee fines Connect with my very knowledgeable guests Arnaldo Rodrigues - LinkedIn Luca Lange - LinkedIn Chris Meier - LinkedIn Dario Burger - 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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    47 mins
  • Freshness and Grinding, Part 1: Protecting your coffee’s flavours
    Apr 22 2024
    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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    50 mins
  • What Is Good Science? Part 2: How to think like a scientist
    Apr 8 2024
    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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    55 mins
  • What Is Good Science? Part 1: How to brew coffee like a scientist
    Mar 25 2024
    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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    46 mins
  • Organic Coffee, Part 2: Why don’t we see more organic coffee farms?
    Mar 13 2024
    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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    41 mins