How to roast better coffee | an interview with Rob Hoos

In this interview, coffee roasting expert and educator Rob Hoos shares the fundamental principles behind roasting great coffee — from the most impactful decisions down to the details that barely matter. If you roast at home or are moving into professional roasting, this is one of the most information-dense hours you'll find on the topic. 🔥 What this interview covers: • The hierarchy of roasting decisions — what actually changes flavor vs. what doesn't • How to roast naturals, washed, and honey processed coffees differently • Roast degree, development time, and why color is the #1 driver of flavor • How to roast for espresso vs. filter • Bean density, moisture content, and how they affect your roast approach • The most common roasting defects (scorching, tipping, facing, chipping, baked) and how to avoid them • Convection vs. conduction — what it means for your machine choice • How to translate roasting profiles across machines and batch sizes • Whether IBTS is the future of bean temperature measurement ▬ Links ▬▬▬▬▬▬▬▬▬▬▬▬ Rob Hoos Website: https://hoos.coffee/ Iteration Coffee (Rob's subscription project): https://www.iteration.coffee/ Rob's book "Modulating the Flavour Profile of Coffee": https://roastrebels.com/en/modulating... Aillio Bullet Coffee Roaster: https://roastrebels.com/en/aillio-bul... Roast Rebels Shop: https://roastrebels.com/en ▬ Chapters ▬▬▬▬▬▬▬▬▬▬▬▬ 0:00 Introduction and who is Rob Hoos 3:08 What is most important to roast a good coffee 10:55 How to roast naturals vs. washed coffees vs. honeys 12:08 Roast degree vs. development time 13:58 How to roast for espresso 15:45 How to reach an even colour through the bean 16:30 Roast degree vs. bean temperature 18:40 Development time vs. development time ratio 21:00 Density and influence on roasting profile 23:56 Moisture content and influence on roasting 27:00 Drying phase vs. Maillard phase 28:40 How to prevent most common roasting defects 34:35 What is baked coffee 38:25 Is convection roasting better than conductive roasting 42:10 How to find the best coffee roasting machine 46:55 What capacity to choose 48:40 How to translate profiles from sample roaster to production roaster 50:30 How to adapt roasting profiles for smaller or larger batches 52:30 Is IBTS the future in coffee roasting 53:40 Where to find more information on Rob Hoos ▬ Key Takeaways ▬▬▬▬▬▬▬▬▬▬▬▬ • Roast color (whole bean and ground) is the single biggest driver of flavor — more than any other variable • Development time controls acidity and fruitiness; time to first crack shapes complexity vs. clarity • Natural processed coffees benefit from shorter development times; washed coffees need more time post-crack • Weight loss percentage (11–13% light, 13–16% medium, 16–18% dark) is a free and reliable roast degree proxy • Bean density determines how aggressively you can roast; low-density coffees are at higher risk of tipping • Scorching comes from excessive conductive heat early in the roast; tipping from too-fast convective heat • When scaling profiles across machines, match color, development time, time to first crack — the curve itself doesn't transfer ▬ About Roast Rebels ▬▬▬▬▬▬▬▬▬▬▬▬ Roast Rebels is Europe's go-to platform for specialty coffee roasting — from home roasters taking their first steps to professionals dialing in production. We source and carry the most proven roasting machines and green coffees in Europe, and we publish content like this to give the roasting community access to the knowledge that actually matters. 🌐 Shop & Resources: https://roastrebels.com/en 📺 Subscribe for weekly roasting content. #coffeeroasting #homeroasting #robhoos #specialtycoffee #roastingprofile #coffeeeducation #ailliobullet #coffeeroaster #developmenttime #roastdegree