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.

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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

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!

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For more coffee science and behind-the-scenes content, follow James on Instagram @filterstoriespodcast.

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The Science of Coffee is a spin-off series from James Harper’s documentary podcast, Filter Stories. 

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Season 3 is made possible by these leading coffee organizations:

The Coffee Quest | BWT | TODDY | Algrano | Probat