Different grades of coffee roasting

The fundamentals of roasting coffee by euCoffia

The specialty coffee market has been experiencing growth for a while now. Baristas always learn new skills, expand their understanding of coffee, and perfect cutting-edge methods. Their line of work has gotten increasingly interdisciplinary over time. However, it seems to me that one of the fundamental coffee-related topics has been overlooked in the development of professionalism. I feel that baristas are more knowledgeable about processing techniques, terroir, and botanical types than roasting coffee. This is no surprise because there is a wealth of trustworthy, fundamental information online regarding what is happening on the plantations. While roasting is still mainly regarded as a trade reserved for the chosen few. What exactly is coffee roasting and what does it entail by euCoffia?

Why is it kept so secret?

In craft roasteries, lighter roasting of premium Arabica is a relatively new and untapped market. Everything was minor as long as the coffee was darkly roasted, which meant that every brew had a fairly identical flavor.

The well-known third wave of coffee forced the roasters(—that is, those who roast coffee—to significantly expand their knowledge, cultivate their analytical and sensory abilities, and acquire a great deal of patience and humility. Geek forums for roasters analyze hundreds of possibilities every day. Truths, half-truths, understatements, myths, and false presumptions are among them. One individual asserts one thing, while the other asserts another. The third one topples both foundations, and the fourth one, who is confident he is correct, opposes all three. Others treat their conclusions and profiles like tiny Amber Rooms, while some roasters collaborate and discuss even the smallest characteristics. Most knowledge is transferred in formal, master-student partnerships. Otherwise, it is learned through various works that have been published, of which none has, to date, provided a fair and thorough compendium of knowledge from A to Z.

coffee in its unroasted state

Green, unroasted coffee, taken right before roasting.
Finally, there are quite a few methods and styles of roasting coffee that produce the required effects. Add to that local choices. In the United States, roast from Solberg & Hansen or Johan & Nystrom is often regarded as underdeveloped and acidic. Additionally, Melbourne coffee is unquestionably excessively black and bitter, according to Goteborg…

Put everything aside for a second. It would be good if as many people as possible had access to the fundamental knowledge of coffee roasting. I’ll make an effort to briefly summarise some of the fundamentals of roasting and, perhaps, provide a basic understanding of what it all entails.


In specialist roasters, coffee is roasted. Shocking! They are mostly what are known as drum roasters. Typically, combustible gas is used as fuel to power them. The most crucial component of such a device is:

It resembles a washing machine somewhat. It spins and is cylindrical. To ensure that the beans travel through the roasting process evenly, cyclically, and rotationally, the drum has paddles inside that scoop the beans.

drum for toasting coffee
At the conclusion of the roast, a coffee roaster is. Photograph by Lumina/Stocksy/Adobe Stock
It is directly beneath the drum. It transforms the fuel that is provided to it into a flame, whose intensity is managed by the operator. Energy is provided by the flame, which roasts the coffee by heating the drum to the right temperature.

Cooling tray:
Located directly beneath the exit, through which the freshly roasted coffee is dropped to finish the roast. The beans must be cooled in order to swiftly put an end to the chemical events that have recently occurred inside of them. So, immediately prior to the drop, the operator fires up the mixer and a different engine that sucks in outside air to cool the heated material. The mixer arms make sure that the coffee beans are distributed evenly throughout the roasting process, just like the drum’s blades do.

Steps for roasting coffee by euCoffia

It’s a straightforward process in which hot air roasts the coffee, which then must escape from the drum. A portion of the raw material’s dust and suspended particles, as well as the smoke produced during the final roasting cycle, also escape detection. The air that cools the beans through a different conduit does the same thing.

for clicking, beginning, switching, and modifying. The captain’s bridge is the command center that is roasting.

The roasting method from euCoffia

A startlingly complicated raw material is coffee. Roasted Arabica beans are thought to contain over a thousand different chemical substances. More than 700 of these are odorants or ingredients that give off a fragrance. The qualities of the ground coffee, not to mention the brew, will completely vary even with very minor changes in the pool of ingredients present in the beans. The reason we can distinguish between the Kenyan SL 28 and the Peruvian caturra so easily has a molecular basis.

Strecker, trigonelline, acidification and Maillard reactions, lipid, sugar, and amino acid breakdown… This is only a small percentage of the most important chemical processes involved in roasting coffee, whose complexity is a challenge to many chemists. In fact, two of them told me that. Here are some fascinating facts, even though it is not appropriate at this time or location to delve into the specifics of these phenomena.

Coffee aroma perception is not simply a fanciful hipster notion. Here are some well-known smells found in specialty-quality Arabica and the underlying chemical components that gave rise to them:

roasted nuts and their aromas: Bitterness from thiophenes, oxazoles, pyrazine, and thiazoles: Caramel and honey from pyridine, phenols, and furans Many substances with a carbonyl group (such as aldehydes), acids, and sugars give thiophenes their fruity flavor.
espresso roasting

VA, the roaster, stood at the roaster as it was roasting.
One further justification for those who continue to support the “arabika>robusta” cause:

Compared to robusta, arabica has roughly 60% more lipids. Lipid-soluble odorants are common; this is crucial for the perception of scents. Simply put, the scents have less “lift” with Robusta.

Coffee that has been roasted contains 34 different acids. The majority of them are volatile molecules that help us perceive fragrance. One of the causes of coffee aging is due to this. More volatile compounds “escape” from your beans the longer you store them.

As the coffee is roasted for a longer period of time,

The acidity drops
The body rises and then falls as bitterness increases, and sweetness rises and then declines.

The renowned crack
For a roaster, the ‘crack’ is a crucial point in the roast. Anyone who has ever produced popcorn using a microwave or specialized equipment (whose operation is similar to that of an oven) has done so using only corn. The water in the roasted coffee beans eventually converts to steam. Pressure increases as time goes on. The fruit starts to fracture and release steam as it gets bigger. Specific sounds that sound similar to the audible removal of air bubbles from the bubble foil mark this particular instant.

The amount of effort and time put into the crack, as well as how the roast progresses from this point to the drop, are what (in terms of roasting) will have the biggest impact on the flavor of the brew. The majority of the time, this step dictates how full, clean, and sweet your Kenya is on the cupping table.

profile of roasting
Here is an example of a roasting profile graph from a well-known program created for roasters.

coffee roasting profile
Exemplary coffee roasting profile. / ed. by Sam

What is occurring to the bean is shown by the two blue lines. These two concepts are complementary ideas. Traditional yin and yang. The reading of the raw material temperature change over time is shown by a falling line and an ascending line. The so-called Pace of Rise, or the rate at which temperature rises over time, is represented by the rising and then declining line. You can see that the value starts off higher and climbs to a certain point, then begins to fall over time. However, this does not indicate that the temperature is beginning to fall. Only its ascent is less. Modern coffee roasting relies heavily on RoR and how it is used.

Simply speaking, RoR is a measure of how quickly chemical reactions occur within the bean. It is therefore of utmost importance. Some important taste reactions may be too sluggish or even absent when the RoR is too low. Papery flavor, roughness, lack of sweetness, and imbalanced acidity are typical cup notes. Too great of a temperature difference between the bean’s outer surface and its center, which will stay somewhat raw, can happen if the temperature rise is applied too quickly. The roasted coffee won’t mature correctly. Notes: There are “green” flavors and scents (peas, grass, asparagus), together with a bitter, smokey sensation. Nothing sweet.

The air temperature inside the device is depicted by the corresponding red graphs. Although they follow slightly different criteria, they are mainly related to the blue charts. The remainder of the image is as follows:

Temperature measurement drops as the roast begins. A well-known falsehood! In actuality, the bean’s temperature begins to rise practically quickly. This is only the probe’s astonishing response to the abrupt drop in temperature brought on by the introduction of a charge at room temperature into the hot furnace. The “turning point” refers to the point at which the curve begins to ascend. We are considerably closer to the truth now than we were before.

the roast’s middle stage. The bean has gained a lot of vitality and is already extremely dry. A significant chemical reaction is about to start. Additionally, this is an excellent opportunity to guide the proper entry into the crack. The stage from crack to drop is frequently regarded as the most crucial part of the roast. The time to choose the energy that will ensure the proper development of the coffee is now.

The roast will cease when the temperature drops. the level of roasting or the bean’s post-roasting hue The RoR controls the rate of reaction, whereas the color controls the roasting intensity. Colorimeters are specialized instruments used to measure it.

The graph of burner power management over time is shown as a percentage in the last section.

Will it be successful to roast coffee at home?

The task of a roaster is intricate and subtle. Is it feasible to successfully roast coffee at home without specialist tools and intricate measurements? Yes, theoretically. As I’ve already stated, roasting coffee is similar to preparing popcorn at home. Naturally, coffee roasted without exact control over the aforementioned factors would not taste exactly like the coffee offered by reputable roasteries. In order to determine whether the game is worthwhile, it is therefore wiser to start with cheaper beans. Therefore, how can I roast coffee at home?

For this, you’ll need an oven, a pan, or a popcorn maker. If you use an oven, it needs to be heated to the highest temperature possible first (usually 280 degrees Celsius). The baking pan should have the coffee beans dispersed equally before being placed in the hot oven. We are unable to manage signs like RoR or variations in coffee temperature when roasting coffee at home. As a result, we do not wait for the first crack outside the oven. Our trials and experiments will determine what happens next, much like roasting in a roasting machine. But keep in mind that the coffee needs to cool down right away after it comes out of the oven.

The guidelines are the same if you decide to pan-roast your coffee. The coffee is transferred to a dry, hot skillet, but you must turn the beans frequently to ensure equal roasting. After watching the beans’ color and waiting for the crack, you take them from the pan and let them cool. The beans don’t need to be mixed if you have a popcorn maker.

That sums up the fundamentals, or more precisely, the fundamentals of coffee roasting. Cheerio!

However, if you want to buy green coffee beans or light roast to dark roast coffee just check our eucoffia shop section and order some freshly roasted coffee at your doorstep.

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