Historically, coffee roasting has been a subjective mix of art and science. While data-driven approaches are now common and sensory evaluation remains essential, many coffees are still not roasted to their full flavour potential. This shortfall occurs because different coffees require different roast profiles; given the numerous variables at play throughout a roast, tailoring profiles for specific coffees quickly becomes complex.

Unfortunately, traditional approaches to tackling these issues fall short on many dimensions. Conscientious roasters have long relied on trial and error to find the right profile for a coffee, a process that wastes a significant amount of time and coffee. Alternatively, some roasters fall back on standardised profiles that simply do not do the coffee justice. This is particularly problematic in sample roasting, where drastically different coffees are often assessed using templated profiles that fail to highlight their best qualities. To solve this problem, Nucleus Coffee Tools designed the Link Coffee Roaster.

About the Nucleus Link Coffee Roaster

As the brainchild of former World Barista Champion Sasa Sestic, Nucleus Coffee Tools applies rigorous science to create innovative equipment that elevates the standards of coffee. The Nucleus Link takes the guesswork out of sample roasting, allowing anyone to roast a coffee in a way that realises its full flavour potential. The Link makes coffee roasting more affordable and accessible, providing roasters with immediate, actionable insights into the coffees they are tasting.

Engineered in collaboration with Kaffelogic, the Link also bridges the gap between sample and production roasting. It provides precision, repeatability, and clear data, offering a high-resolution window into a coffee's true potential. For travels to origin, its portability allows coffee buyers to more accurately assess coffee on location. For commercial roasters, the Link allows you to arrive at an optimal production roast profile quickly. Whether sample roasting for green selection, evaluating microlots for competition, or production profiling on-site, the Link ensures you get the most out of your coffee.

About the Nucleus Link's hardware

The Nucleus Link is a high-precision convection roaster that handles batches from 50 to 100 grams, allowing adjustments in 1-gram increments. Developed with Kaffelogic, the Link utilises the same hardware as the Kaffelogic Nano 7. However, the crucial difference lies in its software: the Link features an algorithm refined by the Nucleus team over years of origin sourcing and competitions. This intelligent software enables anyone to roast high-quality samples without prior experience or access to a commercial facility. You can read more about the software layer below.

Unlike traditional drum roasting, which relies on a pre-heated chamber, every roast with the Link starts at room temperature. This approach ensures the internal bean temperature matches the ambient roast temperature. The gradual temperature climb promotes even development and carbon dioxide dispersion. Because this process reduces the need for degassing, you can cup samples immediately to evaluate a coffee's potential faster. This allows the Link to serve as a powerful communication tool between producers and roasteries, making it the perfect companion for coffee farm visits. It also helps production roasters minimise green coffee waste by eliminating the need for numerous and large sample batches on commercial drum roasters.

The Nucleus Link is completely portable and comes with a waterproof travel case so you can take it with you to assess samples anytime, anywhere. Many world-stage competitors have also used it to roast their competition coffees on-site.

About the Nucleus Link App & Studio

The Link App (free to download for Android & iOS) acts as your control centre for refining every roast, giving you the power to customise profiles exactly how you like them. Using the Link smartphone app, input your altitude (to calibrate fan speed) when changing location. Once that is set, just enter your coffee variety and measure your bean density with the provided tube. You can also enter the screen size and processing method for even more precise profile recommendations. These variables are used to suggest appropriate profiles from a wide selection of curated roast packs which can then be loaded on the Link Studio desktop app (available on Windows & Mac OS). Once roasted, you can easily tweak your coffee's profile based on your tasting notes to ensure you're getting the very best out of every bean. This may be done manually, for those with roasting experience, or with help via the app AI assistant capable of suggesting different profiles and changes to variables as needed.

The Link Studio desktop app (free for both macOS and Windows) offers a comprehensive and ever-growing library of over 1,000 profiles for Cupping, Filter, Espresso, and Omni-roasts. These core profiles are designed as “plug-and-play” solutions for virtually any coffee you may want to roast. The desktop suite allows for advanced live tracking, giving you the flexibility to tweak your preferences and monitor your modifications in real-time as you roast. The Link’s firmware is designed to be a living library and Nucleus frequently releases major updates named after famous coffee regions (e.g. ADDIS 4.1.2). These updates are not just bug fixes, they add hundreds of new power curves and roast plans developed by a network of world-class roasters. Plus, with the automated digital roast log, you can easily store and organise your favourite profiles for future sessions.

Once familiar with the Link’s operation, the desktop Studio app allows you to switch between different operational modes. Basic is the default, keeping things simple with key operational features. Advanced and Export modes grant you more freedom to control back-end parameters and monitoring. For the true tinkerers, Engineer mode unlocks every single attribute of the roaster. Just a heads-up, though: making changes in Engineer mode can affect the roaster’s functionality, so we recommend only diving into those settings if you’re already well-versed with Kaffelogic or Link Studio.

Using the Link for Home Coffee Roasting

In the past, roasting your own coffee was a niche hobby reserved for those with access to commercial equipment or the bravery to roast beans in a skillet over an open flame. Unfortunately roasting coffee well is difficult and many home roasters give up because they struggle to do justice to the green coffees they are buying. To bring coffee roasting to every coffee lover, regardless of experience level, the Link automates the heavy lifting of profile selection while still allowing for manual adjustments via the dedicated app. Users can rely on the system’s consistency to ensure beans are developed evenly, avoiding the common pitfalls of DIY roasting. With the Link, aspiring home roasters can enjoy coffee with minimal wasted batches while also learning about the variables that drive a good roast profile.

Nucleus Coffee Tools also provides an extensive video library with guidance that benefits both amateur and professional roasters.

About Marv the Link AI Assistant

For questions concerning day-to-day use of the Link sample roaster, you can speak to Nucleus’s virtual assistant, Marv, within the LINK App under the ‘Assistance’ section. Or click this link to start a chat. Crucially, Marv acts as a conversational knowledgebase for the entire Nucleus ecosystem. You can ask for details about roast profiles, parameter adjustments, and maintenance practices. Marv can interpret error codes for you, diagnose connectivity issues between the hardware and software, and provide quick alignment steps for sensor calibrations. Marv instantly translates and communicates in over 95 different languages, which includes localised dialects spoken in major coffee-producing origins like Spanish, Portuguese, and Vietnamese. It answers immediate queries regarding how to configure settings within the Link App or on the Link Studio Desktop Software, such as unlocking advanced settings or managing user preferences.

Nucleus Link Coffee Roaster features

• Density-based roasting
• Typical batches roast in 8 - 10 minutes
• Recommended cooling-time - 3 to 4 minutes
• Ambient-start technology allows for immediate cupping
• Extensive profile library, categorised by processing & desired brewing style (Filter, Espresso & Omni)
• Link Studio App enables real-time tracking, data logging & custom profile editing on macOS & Windows
• Altitude calibration suggests fan speed adjustments based on your local elevation
• Travel-ready design with a waterproof travel case

Nucleus Link Coffee Roaster specifications

• Batch capacity: 50 g - 100 g
• Power: 1600 W
• Voltage: 220 V
• Roasting method: Fluid-bed convection
• Connectivity: USB-C
• Dimensions: W 120mm x L 120mm x H 450mm
• Weight:
• Chaff collector: 790 g
• Total roaster weight: 2.6 kg
• Total weight (in travel case): 8.8 kg
• Materials:
• Roast unit: powder-coated steel with plastic fittings (Nylon PA66)
• Roast chamber: aluminium
• Hopper: double-layer borosilicate glass with plastic (Nylon PA66) moulded body parts & replaceable silicone seal

What’s Included with the Nucleus Link Coffee Roaster

• Detachable chaff collector
• Waterproof travel case
• Link density tube
• Nucleus-branded dosing cup
• Sample tray
• USB-C to USB-A connection cable
• Instruction manual