Start with beans from recognized regions. These coffees are often labelled single origin or single estate. While these terms are broad, they generally indicate that the coffee comes from one country, region, or sometimes a specific farm. The more precise the traceability, the more specific the designation becomes, highlighting the producer’s farming and processing methods, and ultimately influencing the flavour in the cup. The distinct flavour profiles are ideal for learning the roasting process. Do I get that typical orange like aroma in my cup with the coffee the Columbian region of Huila? And how do I approach a roast, e.g. the DTR - with a higher bodied coffee? Higher body is quite typical for natural processed coffees from Brazil, gilling basah (wet hulled) from Sumatra.

“Rest is part of the roast”, it’s a cliché in the world of coffee roasters but so true. Resting the beans should be an integrated part of the workflow. When you ignore the resting times of your roasted beans, you are drawn into misleading sensory conclusions. Use our guidelines as a general protocol not as a gospel. Fresh isn’t always better. Beans needs to degas. Excess residual gas destabilises the extraction, gives too much crema and highlights sharpness. So controlled rest improves the structural integration and brings balance. Resting time and the extraction method: Do you roast for filter coffee, less pressure sensitive, please take a resting period of at least 1 - 1,5 week. Take note if the bloom in your prep is not bubbling to vigorously or is neither too flat. For espresso, it will be at least 2 weeks. Espresso is a pressure extraction which is highly affected excess of CO2. It disrupts water contact and causes channelling and gives a lot of crema and sharp notes. Take time to prepare shots over time and test. Resting time and the roast style and bean type: Higher density beans and tighter structure of the beans lowers the diffusion of gas. Light dense roasts release gas more slowly than more porous roasts with darker and less dense beans. The window of optimal sensory quality is shorter with darker roasts.

Use common sense. So avoid contact with moisture and of course oxygen is your enemy, especially with roasted beans. So use and air tight or packaging and limit the times of opening and closing your bags or containers of beans. For green beans: Cool and stable temperature and away from strong odors, ideally 15–20°C / 59–68 °F . A dry environment, target 50–60% relative humidity. At Roast me we store green coffee in breathable protective packaging like GrainPro or similar hermetic liners. This liners are placed in big dark containers ans stored in a temperature stable condition. For roasted beans: Store air tight, avoid moisture, no light, cool but not cold (unless freezing correctly).

A big “NO” is the fridge. The fridge causes condensation and flavour contamination. Freezing, if done properly, is for roasted beans is an option. Freeze only in fully airtight, portioned packaging. Do not refreeze and let the container come to room temperature before opening. And for green beans? the answer is usually no, or rarely necessary. Green coffee is already quite stable when stored properly (cool, dry, stable humidity). Unlike roasted coffee, it doesn’t oxidize rapidly because it hasn’t undergone pyrolysis yet. Freezing can introduce risks like condensation, moisture migration and cell structure stress. Freezing green coffee is only justified in specific situations like long-term archival storage (1–3+ years), preserving rare lots or competition coffees. If you freeze: use vacuum seal or use fully hermetic packaging.

DTR is the percentage of total roast time. It is measured from start of the development phase that occurs after first crack. It has a noticeable impact on flavour and especially the body, but in a nuanced way. The percentage depends very much on the roaster, so absolute indications in percentages are not helpful. So makes notes of your DTR, in many cases software of your roaster will help you to register so you can compare roasts. In general terms: With lower DTR (Shorter Development) sugars and structural compounds haven’t fully developed, and brings a lighter mouthfeel, higher acidity, more clarity and brightness. Too short can feel “tea-like” or even thin if underdeveloped. The other side of the spectrum: higher DTR (longer development) gives fuller body, reduced acidity and if pushed too far, flavours may turn dull, woody, or baked. Technical explanation: During development sugars caramelize, cell structure breaks down, solubility increases, lipids migrate outward. These changes contribute to viscosity and perceived weight in the cup.

The development phase in coffee roasting is the period that begins at first crack and ends when the roast is stopped. It is the final stage of the roast and the phase in which the most decisive flavour changes occur. Before first crack, the coffee goes through drying and Maillard reactions, where moisture evaporates and browning reactions begin. Once first crack starts, the bean structure breaks open and the roast enters development. From this point on, heat application determines how sugars caramelize, how acidity softens, how bitterness forms, and how body increases. During the development phase, caramelization accelerates, aromatic compounds evolve, and solubility increases. The internal structure of the bean becomes more brittle and porous, which affects extraction later during brewing. Lipids migrate outward, influencing mouthfeel and perceived body.

In coffee roasting, the drying phase and the Maillard phase are the two stages that occur before first crack. Together, they prepare the foundation for flavour development later in the roast. The drying phase begins as soon as heat is applied to the green coffee. Green beans contain roughly 8–12 percent moisture. During this stage, that internal water evaporates and the beans shift from a green, grassy aroma to a hay-like smell. Physically, the beans warm up, turn from green to pale yellow, and lose their raw scent. Although few complex flavours are formed yet, proper drying is crucial. If it happens too quickly, the exterior can scorch before the inside is ready. If it is too slow, the roast may taste flat or baked. In short, the drying phase removes moisture and prepares the bean, while the next stage, the Maillard phase builds the structural and flavour foundation of the coffee.

After most surface moisture in the drying phase has evaporated, the roast moves into the Maillard phase. This stage is named after the Maillard reaction, a chemical reaction between amino acids and reducing sugars. It is responsible for browning and the formation of hundreds of flavour and aroma compounds. During this phase, the beans turn from yellow to light brown, and aromas shift toward bread, toast, nuts, and caramel. Body and sweetness potential are largely shaped here. The Maillard phase strongly influences balance and mouthfeel. A longer Maillard phase often enhances sweetness and body, while a shorter one can highlight acidity and clarity. When first crack begins, the roast transitions from Maillard into the development phase, where these newly formed compounds are further transformed.

Taste refers to the basic sensations detected by the taste buds on your tongue: sweet, salty, sour, bitter, and umami. It is a narrow, physiological sense of what you actually “taste” when food touches the tongue. Flavour is a broader perception that combines taste with smell, texture, temperature, and even appearance. Much of what we call flavour actually comes from aroma sensed through the nose. Flavour is largely built from retronasal olfaction , which is the way aroma molecules reach the olfactory receptors in your nose from the back of the mouth while you are eating or drinking. When you chew or swallow, volatile compounds from food travel from the mouth through the throat to the nasal cavity. This is why you can “taste” things like coffee, wine, or herbs even though the tongue itself cannot detect those aromas. In practice, flavour is the brain’s integration of basic taste, retronasal smell, and other signals such as mouthfeel and temperature. Retronasal perception is especially important for complex foods and beverages because it carries most of the nuance that we consciously experience as flavour.

First crack is a key moment during coffee roasting when the beans undergo both a physical and chemical transformation, and you can literally hear it. It is the audible signal that roasting has entered its final and most flavor-defining stage. The sound resembles popcorn popping and marks the beginning of the true development phase. There is also a so-called second crack, a softer and more rapid sound that occurs later and indicates a darker roast profile. At that stage, much of the coffee’s distinct origin character is lost, which is why it is generally not preferred in specialty coffee. During roasting, moisture inside the beans turns into steam and internal pressure begins to build. As the bean structure weakens, the beans expand and eventually fracture. When the pressure is released, the popping sound becomes audible. This is first crack. The transition typically occurs around 195–205°C (383–401°F), depending on probe placement and roaster type. First crack marks the shift from the drying and Maillard phases to the development phase. From this point onward, the coffee becomes drinkable, acidity starts to soften, sugars caramelize more rapidly, and aromatic compounds develop more fully. Everything that happens after first crack determines the final roast level, whether light, medium, or dark. If roasting is stopped shortly after first crack, the cup profile will show brighter acidity, lighter body, and clearer expression of origin and processing characteristics. Extending the roast further enhances sweetness, body, and caramelized notes, while reducing acidity and increasing roast-driven flavors.

Roast profiles describe how heat is applied over time during roasting. They shape acidity, sweetness, body, and aroma development. The key is not just how dark you roast, but how you get there. Light roast profile: The goal is to highlight origin character, acidity, florals, fruit, and terroir. End point will be shortly after first crack. Use a steady but moderate heat during Drying and Maillard. Avoid rushing to first crack; aim for balanced browning. Keep development time DTR relatively short (often 10–15% of total roast time). Best for: High-quality washed Colombians, delicate Costa Ricans, Ethiopians, Kenyans, where clarity matters. Medium roast profile: The goal is to balance origin character with sweetness and body. End point: Mid-development phase, well after first crack but before second crack. Build sufficient Maillard time to enhance caramelization. Allow slightly longer development (14–19%). Reduce heat gradually after first crack to avoid tipping or harshness. Aim for roundness rather than sharp acidity. Dark Roast Profile: If you like to emphasize roast character, bitterness, heavy body, smoky notes and make your coffees ‘unrecognisable’… this is your profile, with an end point approaching or entering second crack. Extend development significantly. Control heat carefully after first crack; too much energy causes scorching. Expect reduced acidity and more roast-driven flavors. Monitor airflow to prevent smokiness from becoming ashy. Best for: old school espresso styles, milk-based drinks and hang-out with friends at Starbucks.

For beginners, drum roasters or hot air roasters are popular because of their ease of use and consistent results.

The temperature varies but generally ranges between 190°C and 225°C, depending on the desired roast profile. There is no single “ideal” roasting temperature because roasting is a dynamic process rather than a fixed set pointWhat matters more than a specific “ideal” temperature is rate of rise, heat stability, and development time after first crack, because flavour is primarily determined by how the temperature changes over time rather than the absolute peak.

Improving home roasting quality is mainly about consistency and your home roast profile, rather than trying to push the roast darker or hotter. Focus on heat management. Avoid applying maximum heat at the beginning. Aim for a smooth temperature rise so the beans dry evenly before browning reactions start. Sudden heat spikes often create baked or uneven flavours. Learn to listen for the first crack. This is the moment when internal moisture pressure causes the beans to audibly pop and expand. Most flavour development happens after this point, so control how long you roast after first crack rather than just chasing colour. Track your roasts. Write down starting temperature, time to first crack, development time, and end temperature. Small adjustments are much more powerful than large changes. Finally, cool the beans quickly after roasting. If beans stay hot in residual heat, they continue to roast and can develop harsh or ashy notes.

A roast profile is basically a temperature–time roadmap of how you want heat to interact with the beans. In the framework often used by the Specialty Coffee Association, quality roasting is about controlling heat application rather than chasing a specific endpoint temperature. Start with the drying phase. For home roasting, aim for a steady but not aggressive heat input during the first 4–6 minutes so moisture evaporates evenly. Watch for the first crack and record the time. Many good home profiles reach first crack around 8–12 minutes, depending on batch size and equipment. Then decide your development time ratio. After first crack, roast for roughly 14–20% of the total roast time if you want balanced sweetness and acidity. Shorter development gives brighter, more floral coffee; longer development increases body but risks bitterness. Keep batches repeatable. Change only one variable at a time — for example, airflow, heat level, or roast duration — and taste the result before adjusting again.

To design a signature home roast profile assuming you are using a precision home roaster such as an IKAWA sample roaster, but the same logic applies to other controllable small batch machines. First decide what style of coffee you want to express. A signature profile is really a flavour philosophy. For example, you can aim for one of three directions: bright and floral, balanced and sweet, or deeper and more chocolate-like. For a precision roaster, start with a gentle but not weak drying phase. A typical approach is to keep heat moderate for the first 3–5 minutes so internal moisture is removed evenly without baking the bean structure. Control the approach to first crack. Many signature profiles aim for a predictable first crack onset, because consistency here shapes the final cup. On a small drum or sample roaster, first crack often occurs around 9–11 minutes, but what matters more is stability rather than the exact number. After first crack, define your development window. If you prefer clarity and vibrancy, try 12- 15% development time relative to total roast duration. If you want more body and sweetness, move to 15 % and higher. On IKAWA-style machines, airflow and heat steps are usually more important than manual stirring or external control. If the machine allows multi-segment programming, use a slightly stronger heat setting early, then taper energy input gradually toward first crack, and finally drop or hold low heat during development. Test the profile repeatedly with the same bean. A signature profile only becomes meaningful when it is reproducible across harvests and batches.

Sour and underdeveloped If your coffee tastes sour and underdeveloped, the roast may have been too short or too cool during the early phase. Try extending the time before first crack slightly or increase heat a little earlier. Bitter, smoky, or ashy If the coffee tastes bitter, smoky, or ashy, development time may be too long or the peak temperature too high. Reduce post–first crack roasting time or drop the beans earlier. Flat, dull, or “baked” If the flavour feels flat, dull, or “baked”, heat may have been too low and too stable. Slightly increase heat during the drying phase to avoid slow internal cooking. No sweetness and complexity If the coffee lacks sweetness and complexity, check the transition into Maillard browning (around the middle stage of roasting). A too-rapid temperature climb here can suppress flavour formation. Finally, always cup your coffee after resting it for 24–48 hours, because roasted coffee continues degassing and flavour stabilisation after roasting. If you want, I can also explain how to design a “signature home roast profile” tailored to your equipment.

Yes, denser beans often require a longer development time, while less dense beans can roast more quickly. Adjust your profile based on origin and variety.