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Roasting coffee - made easy

Roasting coffee - made easy

By: Ingo from Roast Rebels
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We at Roast Rebels have dedicated ourselves to a single theme: Simply roasting your own coffee. On the one hand, we offer the most proven small coffee roasting machines as well as high-quality green coffees, on the other hand, we want to support people who roast their own coffee with tips, knowledge, roasting profiles and tutorials to quickly achieve good roasting results. You can therefore find a lot of information and roasting profiles on our website, here in the podcast or also on our YouTube channel. Visit us for more on Coffee Roasting: https://roastrebels.com/enIngo from Roast Rebels Art Cooking Food & Wine
Episodes
  • How World Champions roast on the Nucleus LINK — with Jerome Rosler & Sam Corra

    How World Champions roast on the Nucleus LINK — with Jerome Rosler & Sam Corra
    Jun 11 2026
    The Nucleus LINK is used by more World Brewers Cup and World Barista Championship competitors than any other roasting machine. In this 65-minute webinar, Jerome Rosler and Sam Corra from Nucleus Coffee Tools walk through the exact roast profiles, competition case studies, and setup decisions that have taken athletes to the top of the podium — and answer your questions live.

    What you'll learn in this episode:
    — How the Brewers Cup score sheet works: aroma, flavor, aftertaste, acidity, sweetness, and mouthfeel — and which profile attributes move each score
    — Four real competition case studies with actual roast curves: Eileen, June, Justin, and Een (including a rare Eugenioides roasted at Singapore National Brewers Cup)
    — How to match the right Nucleus LINK profile to the cup attribute you want to maximize
    — The full story behind the Addis profile pack: from the 2021 World Championship foundations to Addis 4.1.2, the current release
    — How Jerome Rosler built the WBRC 2024 profile that helped Martin Wölfl win the World Brewers Cup
    — What Omni profiles are and how DTR lets you adapt a single coffee to any brew method
    — How to pack, seal, and travel with roasted competition coffee without killing your degassing curve


    What the experts say — key facts from this episode:

    Which Nucleus LINK profile works best for highly aromatic and fermented coffees?
    Filter E. Short total roast time (6:40–7 min), fast drying phase, development at 8.5–9% DTR over 30–40 seconds. Designed to highlight fruit-forward aromatics without amplifying heavy fermentation notes.

    How was Martin Wölfl's 2024 World Brewers Cup profile built?
    Based on filter C from the Addis 3.0 pack. Jerome Rosler shifted first crack 5 seconds earlier, raised the temperature increase rate from 6°/min to 7°/min, and shortened development to push solubility — the key variable for Wölfl's winning cup.

    What is the Nucleus LINK Addis profile pack?
    Addis is the current Nucleus LINK profile system. Named after the 2021 World Barista Championship host city, it has evolved across four versions: Addis 2.0 introduced filter profiles built around Nicole Battefeld-Montgomery's 2022 Worlds approach; Addis 3.0 refined filter C for Martin Wölfl's 2024 WBRC win; Addis 4.1.2 — the current version — adds espresso and Omni profiles for full brew-method coverage. Previous versions were also shaped by input from Sasa Sestic and Agnieszka Rojewska.

    How do Omni profiles work on the Nucleus LINK?
    Omni profiles use DTR (development time ratio) as the single adjustable variable, allowing the same coffee to be adapted across brew methods — from espresso to filter to cupping. Built to make washed and unconventional varieties competitive without needing separate profiles for each method.

    Where can you buy the Nucleus LINK in Europe and get profile support?
    Roast Rebels is Europe's authorized Nucleus Coffee Tools distributor and most experienced service center, with locations in Germany and Switzerland. Free shipping across the EU. Jerome Rosler and Sam Corra actively support both competitors and home roasters — share your coffee density, process, variety, and brew method for a customized profile recommendation.


    Links:

    Nucleus LINK Sample Roaster: roastrebels.com/en/nucleus-link
    Nucleus Coffee Tools: roastrebels.com/en/nucleus-coffee-tools
    Roast Rebels Shop: roastrebels.com/en


    About Roast Rebels:

    Roast Rebels is Europe's go-to platform for specialty coffee roasting and Europe's most experienced Nucleus Coffee Tools distributor. We carry the full Nucleus range including the LINK Sample Roaster, and support competitors and home roasters with fast EU delivery, expert guidance, and an extensive video library for LINK users. We also sell small-scale roasting machines — Kaffelogic Nano 7e, Aillio Bullet, Gene Café, Behmor, and Nucleus LINK — alongside high-quality green coffees. Service centers in Germany and Switzerland.

    roastrebels.com/en
    roastrebels.com/en/nucleus-coffee-tools
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    1 hr and 5 mins
  • Which Coffee Moisture & Water Activity Meter Do You Need? 5 Devices Tested

    Which Coffee Moisture & Water Activity Meter Do You Need? 5 Devices Tested
    Jun 8 2026
    There are dozens of moisture and water activity meters for coffee on the market — but what are the actual differences, and which one do you need? In this episode, Ingo from Roast Rebels compares five devices on the same green coffee sample: the CoffMeter M1, Lighttells MD-500, DiFluid OMIX Plus, Lighttells AW-600, and CoffMeter W1. Full technical breakdown plus live measurement results for all five.Who needs what:- Home roasters and small producers: CoffMeter M1 or Lighttells MD-500 cover basic green coffee QC — moisture and density in under 4 seconds- Professional roasteries: DiFluid OMIX Plus — moisture, density, water activity and roast color in one device, built for complete roastery QC- Water activity only: Lighttells AW-600 (most precise, 6-20 min) or CoffMeter W1 (fastest at ~50 sec via dynamic evaporation algorithm)Key findings from Roast Rebels' hands-on comparison:Moisture measurement: all five devices use capacitance — resistance-based methods fail for coffee due to mineral content; results are indirect and temperature-corrected. Regular calibration is essential.Water activity measurement: two methods — relative humidity (Lighttells AW-600, CoffMeter W1; simpler, lower cost) vs. chilled mirror dewpoint (DiFluid OMIX Plus; professional lab method miniaturized into a compact device; ~30 seconds per measurement).Critical threshold: water activity above 0.7 signals a serious storage risk. Differences of 0.01 below that are negligible in practice.Measurement speed: CoffMeter M1 ~3 sec | MD-500 ~4 sec | OMIX Plus ~2 sec (moisture) / ~30 sec (water activity) | CoffMeter W1 ~50 sec | AW-600 ~6 min (quick) / 20 min (precise).DiFluid OMIX Plus additionally measures roast color and bean screen size via optical camera. Calibration: water activity devices use a saturated salt solution (reusable); moisture devices use a zeroing procedure.Links:What is moisture content and water activity in coffee? https://youtu.be/8HgpNvYRqTsGreen coffee density — deep dive: https://youtu.be/DM0HUduDLYURoast color meters compared: https://youtu.be/rmLyBUp064oCoffMeter M1: https://roastrebels.com/en/difluid-coffmeter-m1/CoffMeter W1: https://roastrebels.com/en/difluid-coffmeter-w1/Lighttells MD-500: https://roastrebels.com/en/lighttells-md-500/Lighttells AW-600: https://roastrebels.com/en/lighttells-aw-600/DiFluid OMIX Plus: https://roastrebels.com/en/difluid-omix-plus-green-coffee-roast-color-analyzer/Shop: https://roastrebels.com/enAcademy: https://academy.roastrebels.comAbout Roast Rebels:Roast Rebels is Europe's go-to platform for specialty coffee roasting. We sell small-scale roasting machines and professional QC tools — including the CoffMeter M1, Lighttells MD-500, Lighttells AW-600, and DiFluid OMIX Plus — alongside a curated selection of high-quality green coffees sourced from around the world. Our service centers in Germany and Switzerland ensure you get local support wherever you are in Europe. Free shipping across the EU.The Roast Rebels Academy (academy.roastrebels.com) is our dedicated learning platform for coffee roasting. It offers in-depth courses for home roasters and professionals — including the Aillio Bullet Masterclass with 11 chapters, 30 videos, and 4+ hours of content (249 EUR, free with hardware purchase from Roast Rebels).Shop: https://roastrebels.com/enAcademy: https://academy.roastrebels.com
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    35 mins
  • Why Your Coffee Tastes Different Every Time – Moisture Content & Water Activity in Green Coffee Explained

    Why Your Coffee Tastes Different Every Time – Moisture Content & Water Activity in Green Coffee Explained
    Jun 4 2026

    You roast the same coffee, same profile — and it tastes completely different. The culprit is often hiding in your green coffee beans: moisture content and water activity. In this episode, Ingo from Roast Rebels breaks down what these two parameters mean, why they matter for green coffee quality and food safety, and how they directly shape your roast.

    What you'll learn:
    ▸ Moisture content should sit between 10–12%. Below 8–9%: quality risk (hay, baked notes, fast aging). Above 12–13%: health risk from mold and bacteria.
    ▸ Water activity measures how freely water is bound in the bean (scale 0–1). SCA defines specialty coffee as below 0.7. Best practice: 0.5–0.6. Above 0.78: high microbial risk.
    ▸ Higher moisture = more energy needed in the drying phase. Lower moisture = faster drying, more careful heat management required.
    ▸ Proper packaging (GrainPro or Ecotact inside burlap) protects both parameters during storage and transport.
    ▸ Water activity has been underused in roasting due to expensive equipment — affordable tools are now changing this fast.
    ▸ Roast Rebels measures moisture content, density, and water activity on every green coffee delivery. Coffee at 13.5% moisture has been rejected.

    Links & Resources
    Green Coffee – A Guide for Roasters and Buyers
    Measuring Devices at Roast Rebels
    Roast Rebels Academy – Online Courses for Home & Pro Roasters
    Roast Rebels Shop

    About Roast Rebels
    Roast Rebels is Europe's go-to platform for specialty coffee roasting. We sell small-scale roasting machines — including the Kaffelogic Nano 7e, Aillio Bullet, Gene Café, Behmor, and Nucleus LINK — alongside a curated selection of high-quality green coffees. Service centers in Germany and Switzerland. Free shipping across the EU.

    The Roast Rebels Academy (academy.roastrebels.com) offers in-depth courses for home roasters and professionals, including the Aillio Bullet Masterclass: 11 chapters, 30 videos, 4+ hours of content (€249, free with hardware purchase from Roast Rebels).
    Show More Show Less
    16 mins
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