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! 

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Explore Mahlkönig’s range of world leading grinders, trusted by baristas globally.

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 Gagné’s writings on grinding

Read up on Samo Smrke’s work on coffee fines

Arnaldo Rodrigues - LinkedIn

Luca Lange - LinkedIn

Chris Meier - LinkedIn

Dario Burger - Instagram

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

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.

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Leave a 5 star rating on Spotify

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Explore Mahlkönig’s range of world leading grinders, trusted by baristas globally.

Do a Certificate of Advanced Studies with the Coffee Excellence Centre

Pick up a copy of the SCA’s Coffee Freshness Handbook

Samo Smrke - Instagram

19 Grams Coffee Roasters in Berlin - Instagram

Arnaldo Rodrigues - LinkedIn

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

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. 

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Discover this episode’s sponsor BWT’s water filtration products. I use their Penguin magnesium filter cartridges and cafes can use their BestAqua ROC

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

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

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

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!

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Leave a 5 star rating on Spotify

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Bring out vibrancy in your coffee with BWT’s magnesium water filters for the home and cafe

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

Morten Munchow - Coffee Mind website

Becky Bleibaum - LinkedIn

Samo Smrke - Instagram

Sophie Vo - LinkedIn

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

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.

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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

Lalo Perez Varaona - LinkedIn

Jorge Cuevas - LinkedIn

Andrea Futterer - GEPA website

Osman Contreras - LinkedIn

Roberto Rene Gonzales - Farm website

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

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

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?

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

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

Lalo Perez Varaona - LinkedIn

Tommie Hooft van Huysduynen - LinkedIn

Alison Streaker - LinkedIn

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

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.

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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

Sverre Simonsen - LinkedIn

Callum Gilmour - LinkedIn

Veronica Balduc - LinkedIn

Morten Münchow - Coffee Mind website

Scott Rao - Instagram

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

What flavours do you want from your coffee?

Every coffee bean begins its life green. And if you brewed it up without first roasting it, you’d get a yellow-green cup of grass-flavoured water.

But, as soon you apply heat to a bean, the flavour can morph to from something quite vegetative to a very acidic unripe fruit, then a very sweet fruit, and eventually dark roasted flavours.

This is the magic of coffee roasting!

In this episode of The Science of Coffee, I show you a full roast in action on the ROEST P3000, taste how coffee flavours evolve from acidic to bitter, and speak to leading coffee roasting scientists to reveal the mind-bending chemical and physical transformations taking place.

See for yourself Roest's innovative P3000 fully automatic roaster.

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Mark Al-Shemmeri - LinkedIn

Callum Gilmour - LinkedIn

Veronica Balduc - LinkedIn

Anja Rahn - LinkedInIldi Revi - LinkedIn

Samo Smrke - Instagram

Morten Münchow - Coffee Mind website

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

Ever wonder why you and your friends can taste the same coffee, but you can’t agree on the flavour notes?

Join me as I explore this metaphysical mystery! I speak with leading scientists and ask: are the flavour receptors in your nose and mouth the same as mine? How does music and the shape of a cup affect what we taste? What about our different cultural backgrounds and language?

Best of all, I put all these questions to the test in the Athen’s World of Coffee trade show. Many poor unsuspecting Filter Stories spit, splutter and gasp in the name of science!

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See Marco Beverage Systems' SP9 for yourself, and discover their range of consistent and energy-efficient coffee brewers for your cafe.

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Helene Hopfer - LinkedIn

Joel Mainland - LinkedIn

Fabiana Carvalho - Instagram

Janice Wang - LinkedIn

Felipe Reinoso - LinkedIn

Freda Yuan - Instagram

Mandy Naglich - Instagram

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