Filter Stories - Coffee Documentaries

Science: The magic of soil

Filter Stories - Coffee Documentaries

Show Notes

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 Use ProfilePrint to find the coffee your customers loved last year (without a week of cupping!). Use promo code "FILTER" to get 10% off your first year of a Mini Beluga subscription. Click here to discover ProfilePrint's many uses.

Support hundreds of thousands of coffee farmers with Fairtrade. Discover how here.

What kind of racing car does the Gaggia Classic GT home espresso machine remind you of? Use discount code FS202610 to get 10% off.

More from Filter Stories - Coffee Documentaries

Oct 12, 2026

This episode takes you through the basics of good water for coffee. To objectively assess a coffee's quality, both producer and buyer need to taste it using the same water. But whose water standards should you choose? Why do roasters often get to define what the "right" water is? What would the coffee world look like if producers set quality standards instead of roasters? Part of The Coffee Producer Toolkit, a series made in collaboration with Lucia Solis, it will help you understand coffee farming better than most professionals you'll meet at a trade show. Each episode takes one part of the farming business — agronomy, processing, fermentation, storage, quality, sales — and lays out what the best farms are actually doing. Related podcast episodes: James: Filter Stories: How Heat Transforms Coffee Beans Filter Stories: How to Be a Better Taster Filter Stories: Getting Great Water, Step by Step

Oct 12, 2026

This episode is a practical guide to tasting coffee, sample roasting and judging quality, built for small producers on a tight budget. That makes it just as useful if you’re early in your coffee journey and want to learn the basics without spending thousands on equipment, starting with a frying pan or a $30 popcorn popper. If you work in coffee, it reveals the obstacles producers face when they try to discuss quality on equal terms with buyers in the global north. Part of The Coffee Producer Toolkit, a series made in collaboration with Lucia Solis, it will help you understand coffee farming better than most professionals you'll meet at a trade show. Each episode takes one part of the farming business — agronomy, processing, fermentation, storage, quality, sales — and lays out what the best farms are actually doing. Related podcast episodes: James: Filter Stories: How Heat Transforms Coffee Beans Filter Stories: How to Be a Better Taster Filter Stories: Getting Great Water, Step by Step

Sep 28, 2026

What is the right price for coffee? This episode shows what the journey of price discovery looks like from the perspective of a coffee farmer. Part of The Coffee Producer Toolkit, a series made in collaboration with Lucia Solis, it will help you understand coffee farming better than most professionals you'll meet at a trade show. Each episode takes one part of the farming business - agronomy, processing, fermentation, storage, quality, sales - and lays out what the best farms are actually doing. Related podcast episodes: Lucia: #64: "What Kind of Coffee Lover am I? How Much am I Willing to Pay for a Cup of Coffee?" James: Filter Stories: The Hard Business of Selling Beautiful Coffee Follow us through our newsletters and Social media: Lucia’s Newsletter James’s Newsletter Lucia Instagram James’ Filter Stories Instagram People mentioned in the episode: Karla Boza — Jacinta Y Su Cafe, San Benito, El Salvador Julia Ortega, Finca Los Pinos, Puebla Mexico Edilberto Tovar — Finca La Esmeralda, Huila, Colombia Melissa de Gasperín — Rancho San Felipe, Veracruz, Mexico Diego Robelo — Aquiares Estate, Turrialba, Costa Rica Cristian Reyes — Finca El Rodeo, Santander, Colombia César Marín — Chacra D'Dago, Peru Gilberto Baraona — Los Pirineos, Usulutan, El Salvador Lalo Perez, Biofilia ASOPEP, Planadas, Tolima, Colombia Piedras Azules cooperative, El Salvador Agnes Thieleke, InterAmerican Coffee Europe

Sep 28, 2026

This episode explores the strange world of the C market, where movements in the Brazilian currency or rebels boarding a random container ship decide the worth of a Colombian farmer's coffee. Yet specialty coffee still uses this number to price the coffees it says are anything but a commodity. Part of The Coffee Producer Toolkit, a series made in collaboration with Lucia Solis, it will help you understand coffee farming better than most professionals you'll meet at a trade show. Each episode takes one part of the farming business - agronomy, processing, fermentation, storage, quality, sales - and lays out what the best farms are actually doing. Related podcast episodes: Lucia: #64: "What Kind of Coffee Lover am I? How Much am I Willing to Pay for a Cup of Coffee?" James: Filter Stories: The Hard Business of Selling Beautiful Coffee Follow us through our newsletters and Social media: Lucia’s Newsletter James’s Newsletter Lucia Instagram James’ Filter Stories Instagram People mentioned in the episode: Karla Boza — Jacinta Y Su Cafe, San Benito, El Salvador Julia Ortega, Finca Los Pinos, Puebla Mexico Edilberto Tovar — Finca La Esmeralda, Huila, Colombia Melissa de Gasperín — Rancho San Felipe, Veracruz, Mexico Diego Robelo — Aquiares Estate, Turrialba, Costa Rica Cristian Reyes — Finca El Rodeo, Santander, Colombia César Marín — Chacra D'Dago, Peru Gilberto Baraona — Los Pirineos, Usulutan, El Salvador Lalo Perez, Biofilia ASOPEP, Planadas, Tolima, Colombia Piedras Azules cooperative, El Salvador Agnes Thieleke, InterAmerican Coffee Europe

Sep 14, 2026

This episode explores what a trade show actually feels like for a farmer who flew in on money his community pooled together, why a sausage dog opened a door that hundreds of cold emails couldn't, and why learning English may be a better investment for a farmer than a longer fermentation. Part of The Coffee Producer Toolkit, a series made in collaboration with Lucia Solis, it will help you understand coffee farming better than most professionals you'll meet at a trade show. Each episode takes one part of the farming business — agronomy, processing, fermentation, storage, quality, sales — and lays out what the best farms are actually doing. Related podcast episodes: Lucia: #54: Visiting Producers, Advanced Tourism & The Coffee Hunter (farm visits, the buyer relationship) #56: Pranoy Thipaia (finding export markets, expo advice) #65: To Blend or Not to Blend? Wine Vintages, and Harvest Update (sales strategy, consistency over novelty) Cabal Cafe Podcast en Espanol

See all episodes →