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...

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...

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...

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...

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...

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...

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...

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...

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...

So you’ve just taken a sip of a very rare coffee, and flavours of passion fruit explode in your mouth. But here’s the thing: that flavour of passion fruit is not coming from your mouth. It’s not even coming from your nostrils. It’s being picked up behind your eyes! In this first episode of The Science of Coffee's second series, I unravel how our sense of smell and taste works to help you be a better coffee taster. I shrink us down microscopically and we dive into your tongue to show you...

We’re back with another series of The Science of Coffee! Across 10 science stories, narrative audio producer and coffee professional James Harper takes you on a journey into coffee's hidden microscopic secrets. James has spent the last year traveling to Central America, Greece, Norway, Switzerland and interviewing dozens of the world’s leading coffee scientists. This insights will help you appreciate coffee more deeply and make even better coffee at home. We'll explore organic coffee...

Imagine you’ve got a cup of coffee in front of you. You haven’t tasted it yet. You therefore don’t know what it tastes like, right? Wrong. Some scientists argue that you actually do know what it will taste like (more or less), and the act of tasting simply confirms what you have already imagined it will taste like. And that’s because a growing body of research is revealing that sight, sound and touch all affect your expectation of a coffee’s flavours. In this episode, I explore how...

When was the last time you picked up a cappuccino with a mountain of foam perched on top? Maybe these are the cappuccinos you make every morning at home. I personally really, really dislike them! The foam is cold, raspy, and gets in the way of the actual coffee liquid. How much better would your mornings be if, instead, your cappuccino had that creamy, silky “microfoam” you find in a specialty coffee cafe? In this episode, I take you deep into the bubbles of latte foam to show you what...

A good espresso is a sublime experience: rich, sweet, and wonderfully caffeinated. But, who woke up one morning and thought to themselves, ‘I’m going to build a contraption that forces a tiny amount of super hot water with incredible pressure through a bed of very finely ground coffee’? Well, the fact is, the first “espresso” machine built 150 years ago was awful in almost every way. Worst of all, if you gave that coffee to anybody on the street, nobody would say it’s even an...

How can you make better coffee at home? Well, an easy way is to buy higher quality beans. But, I’m concerned this is going to get harder and harder for you in the future. Climate change is making coffee taste worse while also pushing farmers into financial hardship. In this episode we explore how genetic development can produce a coffee tree that might save the day. Is there a wild coffee tree happily growing in the forests somewhere that could be our silver bullet? What about if we mix...

How you brew your coffee dramatically affects what you taste. And I do mean dramatic! Brewing up the same bag of coffee beans can taste like a slice of heaven, or a slap in the face. So, what exactly is happening at a microscopic level when water swirls through coffee grinds? Why does boiling water extract certain flavours, while letting the kettle cool for five minutes make it taste markedly different? In this episode, we dive deep into the academic research conducted at the UC Davis...

Water really matters when you’re brewing coffee. Different waters can dramatically change how a single coffee will taste. But what is the right water for the best coffee? In this episode I will give you the answer, but I will first take you back billions of years to tell you the story of a single mineral and how it's responsible for making our coffees taste lame. Because here’s the thing: water science is chemistry, and chemistry is very complicated and easily forgettable. But with a...

The Science of Coffee is a journey into coffee's hidden microscopic secrets to help you make even better coffee at home. Across six episodes, documentary maker and coffee professional James Harper takes you deep into the world of water for coffee, coffee extraction, plant genetics, espresso technology, latte foam and sonic seasoning. Press the Subscribe button so you don't miss future episodes! The Science of Coffee is a spin-off series from James Harper's documentary podcast Filter...