It is noteworthy to remember that some charts might have more or fewer roasting distinctions compared to what is presented here. We included the steps that are significant in the roasting process, rather than recording too much detail or oversimplifying the procedure.

DARK ROAST VS. LIGHT ROAST

Individuals typically have different inclinations when it comes to what extent of the espresso preparing cycle they like, even though they possibly don’t think about the different names. The simplest and most common classification for roast levels are Light, Medium, Medium-Dark, and Dark Roast.

It is possible that there might not be any dissimilarities in the manner of roasting a Full City and Full City Plus since both of them are Dark Roasts. Nevertheless, the roasting method for a City roast is distinct from that for a French Roast.

As beans roast, their internal temperature rises. With the roaster temperature increasing, different considerations must be kept in mind. The types of roasting are typically distinguished by the internal temperature of the beans when they are taken out. Let’s analyze the hotness of the beans required to attain the desired roast.

LIGHT ROAST

You need to have an internal temperature between 356-401°F to make a light roast coffee. Light roasts may be known as light city, half city, or cinnamon roasted. No matter what they call it, they usually happen close to the first noise when something breaks. At this moment, the surface of the beans is still arid, and they could possibly be very solid (especially if they are taken out before the initial rupture).

If you like brewed coffees that are more acidic or have a brighter taste and are lighter in body, you should choose this type of roast. This type of roasting is ideal to do in the home since it is quicker and involves maintaining a lower temperature.

MEDIUM ROAST

For medium roasts, such as city and city+, aim to have the bean temperature between 410-428°F. The beans will appear somewhat dry on the outside, but they will be much easier to tell apart from the green beans. This roast is indicated by the beginning to end of the initial popping noise. It is sometimes thought that any coffee that is roasted between the first and second crack levels should be considered a medium roast.

This type of roast is preferred to lighter roasts due to its milder acidity and stronger body. Plus, the temperature is still manageable for most people.

High Agtron scale Differences -Coffee Roast Techniques ! User’s Practical Roasting Experience

High clarity & high uniformity

Examining the bean, if there is minimal color contrast between the center part and the outer layer, this indicates that the beans have been roasted evenly and the taste is generally pure, such as the fruity tones of light roasts and the bittersweet flavor of darker roasts.

Multilayered 

Examining the cross-section of the bean, if there is a major colour contrast between the interior and exterior, that would indicate a variation in the roasting level. Hence, you can savor the flavor of this coffee, which blends light and dark roasts–such as the Nordic style of roasting–for an intricate arrangement of taste. The light roast provides a fruity aroma, while the medium roast is decidedly more mellow.

Despite the difference in roasting time between the inside and exterior of the bean, if it is baked lightly, the outside will have a roasted appearance while the center may still be uncooked. There is a likelihood of obtaining coffee which has an unroasted, grassy flavor. The core having an increased water content causes frequent chemical reactions, bringing about swift alterations in the taste. It is not easy to make it taste consistent.

The final outcome of flavour ultimately depends on what you personally like and the techniques you employ. Whether you prefer a simpler, pure taste or something with more depth depends solely on your preference.

Are you excited to give it a try now that you know the distinctions between the two? How can I make two different styles of roasting?

Learn the differences caused by techniques from a scientific point of view

From the principle of physics- heat transfer:

1. Various heating techniques like hot air and infrared radiation provide an even amount of heat allowing for a more genuine taste. 2. The technique of ‘contact conduction’ heating of the drum entails the drum to be at a high temperature, which is then applied to the outside of the bean gradually heating the center. The outer part of the bean will be cooked before the insides, which will result in a more complex taste.

It takes time to transmit the heat from the bean surface to the core so the roasting speed will be one of the most important factors to the layers:

1. Cooking at a high-speed results in a shorter roasting period. When the outer part of the bean is cooked first, and the inner part isn’t, the flavor will be complex and varied. 2. Instead of quickly roasting, if more time is taken to cook the food by simmering and allowing the heat to be evenly spread throughout the core. The slower the roasting process goes, the more even the resultant product will be and the more pure it will be.

Once we are familiar with the two primary elements, we can use the rules of thermal conduction and grilling velocity to come up with distinct tastes?

1. A hot-air roaster produces a complex flavor profile in a shorter roasting time, due to its limited direct heat contact. An example is the Loring roaster, which can complete the cooking process very quickly in a span of three minutes. 2. Cooking with a combination of traditional hot air and direct heat results in optimal temperatures that make gentle simmering easier and improve the evenness and quality of the hot air flow. 3. Roasting with higher heat and intense hot air in a cast iron vessel adds additional layers of flavor. 4. Infrared radiation heating technology enables achieving both a high level of purity and high uniformity.

Rubasse digital infrared roaster has three main types of heating methods: 

• Heating by shortwave Near-infrared direct irradiation and penetration: please find for more information 17 key points to Consider Before Purchasing your First Coffee roaster
• Hot air convection conduction: The main design concept of Rubasse convective exhaust system is that: the cold air passes through the glass tube in the centre part to cool down the heated infrared lamp and the cold air will therefore turn into hot air. The hot air spreads from the end of the glass tube to the drum and finally is exacted away from the front end. In addition to the complete utilisation of all the heat generated by the lamp, the heat dissipation also extends the life of the lamp. More importantly, through the adjustment of the fire and the damper, we can control the proportion of the hot air in the heat energy
• Contact conduction?

The infrared energy needs to be able to go through the glass tube of the lamp to warm the beans, so the glass tube must be heated to a high temperature. Heat does not move through the drum by way of conduction as the drum is a closed off area, which does not allow for infrared rays to pass through. Except for using infrared to warm up the beans, the rest of the infrared radiation will hit the iron pot and heat it up as well. If the iron pot of the Rubasse roaster reflects the infrared radiation and this radiation gets absorbed by the beans or the pot itself, it will eventually become very hot due to the contact heat generated from the absorption. By altering the intensity of the fire and the rate that the drum is revolving, the amount of heat transfer can be regulated.

Multi-layered roasting

• Drum with low-speed rotation: increase the heat conduct proportion 
• Exhaust with low-speed rotation: multi-layered roasting technique.
• Fast roasting: to create and facilitate the differences between layers. 
• Turn down the damper: to reduce the convection proportion.  

High uniformity roasting 

• Drum with high-speed rotation: to cut down the radiation proportion of infrared. 
• Exhaust with high-speed rotation: high purity roasting technique. 
• Low roasting: to create and facilitate purity, fragrance and sweetness. 
• Turn up the damper: to increase the convection proportion.