How Do Coffee Roast Levels and Coffee Roaster Types Interact?

Coffee roast levels run from light to dark, and each level shifts the balance of acidity, sweetness, and bitterness in the cup. Light roasts hold on to floral and fruity notes, medium roasts round out sweetness and body, and a deep roast pushes dark chocolate and smoky tones while muting origin acidity.

Inside the drum, heat drives caramelization and the Maillard reaction, which build aroma and color as green beans turn brown. Coffee roaster types differ in how they move that heat, and the curve must be adjusted for every new green bean. The goal is repeatability: the same bean should taste the same from one batch to the next.

Coffee roasting is the core stage that determines the flavor direction of a cup of coffee. From green beans to the beverage in the cup, the degree of roasting directly governs the balance of acidity, sweetness, and bitterness. This article systematically sorts out eight common roast levels, the working principles of three types of coffee roasters, and the mechanisms by which caramelization and the Maillard reaction shape flavor. At the same time, it records in detail Front Street Coffee's operational procedures and curve management experience in actual roasting, helping coffee enthusiasts build a complete cognitive framework from theory to practice.

Friends who drink coffee regularly all know that coffee beans can be divided into different levels according to roast depth, and the flavor direction and taste experience brought by each roast level are completely different. As a café that insists on roasting in-house, Front Street needs to complete dozens of batches of coffee bean roasting every day. Whether it is light-roasted Yirgacheffe or medium-roasted Brazil coffee, their flavor characteristics are already thoroughly familiar. When facing newly arrived green beans, the roasting curve still needs to be repeatedly adjusted. It can be said that coffee roasting is a craft that requires long-term study. Next, Front Street will talk about some insights regarding roasting.

The essence of coffee roasting is to apply heat to green beans, prompting a series of physical changes and chemical reactions inside and on the surface of the beans. In this process, various tastes such as acidity, bitterness, and sweetness are gradually generated, while body and color are also shaped, ultimately transforming pale green green beans into dark brown roasted beans.

The core pursuit in the roasting process is consistency of quality, in other words, the repeatability of the roasting result.

For consumers, the most disappointing thing is nothing other than unstable coffee quality—the same bean tasted completely different last time compared with this time. Even though the brewing method has not changed, the taste is like two different things. This kind of situation precisely tests the roaster's skill. "Consistent quality" sounds easy, but truly putting it into practice is by no means easy.

Front Street Coffee believes that one fact cannot be ignored: there are simply too many factors that can affect the roasting result. In addition to uncontrollable variables such as green bean quality and weather conditions, the links that also need human regulation include adjustment of firepower, whether the airflow damper is clean enough, whether the gas supply is stable, and so on. To ensure that the roasting of a certain bean is always stable, the roaster must keep detailed records of parameters for every batch, including charge temperature, charge weight, turning point, boiler temperature per minute, dehydration point, first crack point, first crack time, discharge time, dehydration rate, rate of temperature rise, and so on (the more detailed, the better). The reason is that tiny fluctuations in temperature and heat during roasting are enough to change the bean's final taste, and different bean varieties each have different characteristics. In addition, roasting itself is work that requires quick judgment and operation within a short time, so the roaster must be able to accurately predict the roasting progress and correct the curve through cupping.

Before formally learning coffee roasting, let us first understand several of the most common types of coffee roasters currently available: 1. Direct Fire Roaster

2. Half Hot Air Roaster

3. Hot Air Roaster

Before starting roasting operations, it is necessary to first understand the basic structure of a coffee roaster. Front Street Coffee currently uses a Yangjia Feima 600g coffee roaster (Half Hot Air Roaster).

Detailed explanation of coffee roaster types:

1. Hot Air Type

The hot air roaster works by using a blower to draw in air, then letting the air pass through heating coils to raise the temperature, using hot air as the heat source to roast coffee beans. Hot air can not only provide the temperature required for roasting, but also use the force of the airflow to turn the coffee beans, achieving two goals at once.

Advantages: Excellent thermal efficiency, rapid temperature rise, relatively even heating of green beans, and easy to control in operation.

Disadvantages: Precisely because the heating efficiency is extremely high, a slight lack of attention can cause the temperature to rise too violently, causing the beans to be "underdeveloped," and if the temperature rises too high, it is easy for the caramelization reaction to proceed insufficiently.

Flavor characteristics: Prominent acidity, clean and pure flavor, but lacking in layering and richness. During deep roasting, it is prone to producing irritating off-flavors.

2. Direct Fire Type

As the name suggests, the direct fire type lets flame directly contact the coffee beans for heating. In its development to the present day, the "fire" in direct fire roasting includes not only traditional gas stove flames and charcoal fire, but also forms such as infrared and electric heating tubes.

Advantages: The roasting time is relatively longer, the caramelization reaction proceeds more fully, and the flavor layers are richer.

Disadvantages: It is prone to uneven roasting, and if the heat is not controlled properly, it is also easy to scorch the beans, producing a burnt bitter taste.

3. Half Direct Fire, Half Hot Air Type

This roasting method combines the advantages of both the direct fire type and the hot air type, and is currently the mainstream choice in commercial roasting equipment. Half direct fire roasting is relatively close in principle to direct fire roasting. The difference is that the outer wall of the roasting container has no openings, so the flame does not directly contact the coffee beans. At the same time, the machine is also equipped with an exhaust device that introduces hot air outside the roasting container into the roasting chamber to improve efficiency. This exhaust device also has another function: to suck away the detached silver skin (the thin film attached to the outer layer of the coffee seed), preventing the silver skin from burning in the high-temperature roasting chamber and affecting the flavor of the coffee beans.

Half direct fire, half hot air machines have both the advantages and disadvantages of direct fire and hot air types. In actual operation, the heating method can be changed according to adjustments to the hot air volume and boiler rotation speed. The larger the hot air is opened and the faster the rotation speed, the more it leans toward the hot air type; conversely, the closer it is to the direct fire type.

This type of household roaster uses an alcohol lamp or gas lamp as the heat source, while larger models directly use the flame on a gas stove as the heat source. Its advantage lies in intuitive operation, making it easy to judge the degree of roasting, and silver skin cleaning is also relatively convenient, but the disadvantage is that the roasting temperature is not easy to control precisely.

How Front Street operates a hand-cranked half direct fire drum roaster

1) Pour the green coffee beans into the roasting drum. The amount of green beans is determined by the size of the drum, then seal the drum;

2) Light the heat source and turn the handle at a constant speed to rotate the roasting drum, so that the beans inside tumble evenly;

3) When roasting reaches 3 to 4 minutes, the beans in the drum begin to turn yellow, the silver skin falls off, and the aroma gradually emerges;

4) When roasting reaches 6 to 7 minutes, the beans in the drum have turned brown and begin to emit white smoke, and by around 8 minutes they enter first crack;

5) At about 10 minutes, first crack ends. If a lighter taste is preferred, the beans can be discharged at this point. Otherwise, continue roasting and wait for second crack;

6) At 12 minutes, second crack is complete. At this point, discharge the beans quickly, cool them with an electric fan, and the roasting is finished.

How Front Street determines the coffee roast level

Green beans—each coffee cherry contains two green beans, and at this stage the aroma is still hidden within them, waiting to be awakened. Green beans contain a large amount of chlorogenic acid. As roasting progresses, chlorogenic acid gradually decomposes and disappears, releasing familiar and pleasant fruit acids—such as acetic acid, citric acid, and malic acid, which is also found in wine. When roasting is just right, these pleasant acidity notes can be appropriately expressed; conversely, if roasted too much, they will be completely masked.

When roasting proceeds to 5-7 minutes, the beans begin to release moisture, the color changes from pale green to orange-yellow, and they give off a unique aroma similar to creamy roasted vegetables.

Light Roast—When the beans emit their first soft crack, their volume expands at the same time, and the color changes to an appealing cinnamon color, so it is also called cinnamon roast or half-city roast. Acidity dominates the flavor expression of light-roasted beans, and the texture and mouthfeel have not yet been fully developed, so they are usually used for canned coffee and are difficult to satisfy the needs of true coffee connoisseurs.

Light-roasted coffee beans

Medium Roast—At 10-11 minutes of roasting, the coffee beans take on an elegant brown color. New Yorkers are accustomed to drinking medium-roasted coffee beans at breakfast, paired with rich milk and sugar, to open a new day, so this roasting method is also called breakfast roast or city roast. Medium roast can both preserve the original taste of the coffee beans and appropriately release aroma, so single-origin coffees such as Blue Mountain, Colombia, and Brazil mostly choose this roasting method.

Medium-roasted coffee beans

At 12-16 minutes, oils begin to emerge on the surface, and the beans are branded and scorched by intense heat into a glossy dark brown, called full-city roast. Some believe that at this point the acidity, sweetness, and bitterness of the coffee reach the most perfect balance, and the personality of the coffee beans is also clearly outlined.

Dark Roast—The darker the coffee beans, the sweeter and more mellow the flavor. At this point the oils have transformed into caramel, with bitterness receding and sweetness returning, and a long finish. It is most suitable for making powerful Espresso coffee, so it is also called Italian roast.

Just-right roasting gives coffee beans life, transforming them into the memorable acidity, sweetness, and bitterness that linger on the palate. However, people who are sensitive to caffeine may want to choose dark-roasted beans as much as possible, because caffeine gradually dissipates during roasting, so the darker the roast, the lower the caffeine content. It is said that the caffeine content in each cup of Espresso is only half that of other medium-roasted single-origin coffees.

Dark-roasted coffee beans

We all know that coffee beans produce flavor and aroma during roasting, so how exactly are this flavor and aroma obtained? What is their connection with the caramelization reaction and the Maillard reaction?

What is the [Caramelization Reaction]?

The sugars in coffee beans undergo caramelization roughly between 170 and 200°C, which happens to be the temperature range of sucrose's melting point (185°C) and the first crack stage during coffee roasting.

The products of the caramelization reaction are divided into two parts:

Dehydration products of sugar, namely caramel or dark brown color.

Cracking products, mainly some volatile aldehydes and ketones.

Overall, the caramelization reaction produces a roasted aroma, caramel, and color, while also generating other aromatic substances such as maltol, Cyclotene, furan compounds, and so on. These compounds can also be found in foods such as red wine, fruit juice, and cream.

However, if caramelization is excessive during roasting, it is not a good thing. Instead, it causes carbonization, making the coffee dry, bitter, and harsh on the throat. If caramelization is insufficient, the aroma will appear monotonous and dull, lacking layers.

Caramelization reaction temperature and coffee roasting

During roasting, three key elements that determine the coffee's final flavor must be properly controlled: acidity, sweetness, and bitterness. Generally speaking, the longer the total roasting time, the less acidity remains in the end; on the contrary, bitterness increases with prolonged roasting time, and the darker the roast, the more bitter the coffee.

It is such a seemingly uncomplicated process, yet it sublimates sugar, breaking through single-dimensional sweetness and incorporating a more visually appealing color and an aroma that better stimulates the appetite. If you cook sugar at home, the whole process is likewise accompanied by an intoxicating aroma.

What is the [Maillard Reaction]?

The Maillard reaction is the most complex of the chemical reactions that occur during coffee roasting, bar none. After the Maillard reaction, the number of flavor substances in coffee beans is more than double that in green beans before roasting. Therefore, the Maillard reaction is one of the most important reactions producing the myriad flavors of coffee.

The Maillard reaction refers to amino compounds (amino acids and proteins) and carbonyl compounds (mainly reducing sugars such as glucose, fructose, lactose, and maltose) undergoing a series of complex reactions to form brown compounds, and then in the later stage of the reaction forming black macromolecular compounds—melanoidins. Therefore, the Maillard reaction is also called a non-enzymatic browning reaction.

The Maillard reaction process can be divided into three stages

1. Initial stage:

Carbonyl-amine condensation, Amadori molecular rearrangement

2. Intermediate stage:

The Amadori molecular rearrangement product fructosamine dehydrates into HMF (hydroxymethylfurfural)

Fructosamine loses an amino group to become a reductone

The action of amino acids with dicarbonyl compounds

3. Final stage:

Aldol condensation

Polymerization reactions that generate melanoidins

During coffee roasting, the Maillard reaction mainly occurs in the stage after dehydration is completed, when the bean color begins to turn yellow and then brown. The reaction continues until roasting ends and the beans are completely cooled before it stops. But when first crack is about to begin, another reaction with an important influence on coffee flavor—the caramelization reaction—is about to start. It will compete with the Maillard reaction for the same reaction raw material—sugar—causing the rate of the Maillard reaction to begin slowing around first crack. Therefore, the so-called main Maillard reaction stage usually refers to the period during roasting from when the coffee beans begin to turn yellow to before first crack. During the reaction, macromolecular compounds called melanoidins are continuously produced, and ultimately more than 600 volatile organic compounds exist in the roasted coffee beans. Thus the Maillard reaction brings flavor, mouthfeel, color, and complexity to coffee.

Therefore, during coffee roasting, the degree of the Maillard reaction can be indirectly regulated by adjusting the roasting pace, thereby adjusting coffee flavor. Since increasing the temperature after 80°C has little effect on the reaction rate of the Maillard reaction, adjustment is usually carried out by lengthening or shortening the reaction time. Extending the Maillard reaction time will produce more macromolecular melanoidins, bringing coffee a heavier mouthfeel and a more complex and deeper flavor profile.

What do first crack and second crack refer to?

As roasting progresses, the temperature of the beans continuously rises.

First crack: The components in the coffee beans begin to undergo various chemical changes, gradually forming the coffee beans' color, bitterness, acidity, and aroma. At this time, water vapor and carbon dioxide are gradually produced inside the beans. These gases increase the pressure inside the coffee beans, so the coffee beans begin to expand. Because the cell walls cannot withstand the constantly increasing pressure, accompanied by crackling sounds, the cellular structure of the coffee beans is destroyed. This is the so-called "first crack."

Second crack: After first crack, some of the produced components begin to decompose while generating heat. During this process, gases are produced, causing the beans to continue expanding. Along with the expansion of the coffee beans, the cells are destroyed again, and crackling sounds are emitted once more. This is the so-called "second crack" and "third crack." After the coffee beans are removed from the roaster and force-cooled, this change stops.

Once coffee beans expand, they will not shrink back. When roasting green coffee beans of the same variety, the size of the coffee beans will determine the method of dark roasting versus light roasting. Light-roasted coffee beans are smaller in size.

Common problems encountered in the coffee roasting stage include the following:

1. The preheating temperature of the roaster is insufficient, and the coffee beans are immediately put into the roaster, resulting in prolonged roasting time. Therefore, roasting loss is large, and the coffee bean color is relatively light. This is because with insufficient heat, the surface cannot fully caramelize, lacking the proper color, and the internal structure is rough.

2. The roaster temperature is too high. When roasting coffee, a hard crust forms on the surface too early, suppressing the expansion of the internal structure. Also, because the surface colors quickly, the operator may mistakenly think the product is already roasted and end roasting early. The inside of such beans is relatively sticky and compact, failing to achieve the proper expansion effect, and also lacking normal aroma.

3. The idle period after preheating is too long. The interior chamber, dry-heated for too long, accumulates too much heat. As soon as the coffee beans enter the roaster, all heat sources concentrate on the bean surface in the earliest roasting stage, forming excessively strong top heat, after which the heat rapidly dissipates. The unstable chamber temperature makes it difficult for the inside of the coffee beans to be fully roasted.

4. Roasting time is too long or insufficient. The level of roasting temperature and the length of time should be adjusted according to the amount of beans. When the amount is small, the roasting chamber has more space, and the thermal energy from metal conduction and radiant heat is greater, so the temperature should be lower; when the amount is large, the temperature can be higher. The length of roasting time also needs flexible adjustment. When beans enter the roaster and are heated, they simply absorb thermal energy from the surface and surroundings and transfer it to the center of the bean, so the roasting condition can be judged by observing changes in the bean surface.

5. Differences in roaster type and performance can also cause differences in roasting time and temperature. From the previous direct fire gas type with top and bottom heat to the electric heating type commonly used now, the convection design of energy is continuously improving. At the same time, adding fans improves thermal convection stability, making the color of roasted beans more uniform, and can also save electricity and roasting time.

Points to note before roasting coffee beans:

Remove defective coffee beans mixed in with the green beans, such as defective beans. Even a single defective bean can affect the taste and flavor of the entire batch of coffee.

The ideal moisture content of green beans is 11-13%. Maintaining such moisture content requires a good storage environment. The humidity and temperature of the warehouse are best maintained at an average of 50% and 20°C.

When preparing to roast, we weigh the green coffee beans to be roasted, then pour them into the hopper on the machine body. Although they are ready to be roasted, sometimes they may still need to wait a while in the hopper. Why is that? This is because before roasting, the roaster needs to undergo a preheating procedure. We set the preheating temperature, and after preheating, adjust to the appropriate chamber temperature setting before the green beans can enter the roaster. This principle is like searing a steak: we rarely put a steak that is about to be seared into a cold pan; when baking a cake in an oven, a preheated oven can bake the cake more evenly and let it rise better. Coffee roasting and cooking share similar principles: they both require a procedure of preheating the tool.

Schematic diagram of green beans

Key One: Warming the drum

Referring to the roaster being used, the basic charge temperature is based on 200°C, so the boiler temperature must first be stabilized above 200°C, with the airflow damper set to maximum. The warming time is about 30 to 45 minutes. After 45 minutes, when the temperature reaches between 200-210°C, warming the drum is considered complete.

If the boiler temperature is 210°C and we need to charge at 200°C, then we can close the airflow damper, let the temperature drop to 200°C, and proceed to the next step of charging beans. It is not recommended to raise the temperature quickly, because in the working principle of a coffee roaster, excessive firepower (gas volume) only increases the surface temperature of the boiler, not the temperature of the entire boiler.

Key Two: Determine charge temperature according to green bean characteristics

Take Papua New Guinea Paradise Bird as an example. It is a Typica variety, belongs to lower-density green beans, and is not very suitable for dark roasting. It naturally has refreshing acidity and fruit aroma. We will choose a medium-light roast, focusing on firepower adjustment after first crack. First judge the basic conditions of the green beans, then decide the roasting method. First of all, it is a washed-process, lower-density, 10% moisture content, 17-year green bean. Based on the existing state of the green bean, the charge temperature is set at 200°C.

Key Three: Firepower adjustment

The roasting process is very tricky. If the fire is too strong, the outside is cooked while the inside is raw; if the fire is too weak, the inside is cooked but overdone. To roast coffee beans consistently inside and out, controlling the heat is the key.

Front Street Coffee's specific roasting operation

Charge when the chamber temperature reaches 200°C, set the airflow damper to 3, after 1 minute of steaming adjust the firepower to 160°C, keep the airflow damper unchanged, adjust the firepower once when the chamber temperature is 160°C, lower it to 115°C, roast until 5 minutes 35 seconds, temperature 152°C, the bean surface turns yellow (Maillard reaction begins), the grassy smell completely disappears, dehydration is complete, adjust the airflow damper to 4 (at this time water vapor is produced, open the damper wider to discharge water vapor);

At the 9th minute, ugly wrinkles and dark streaks appear on the bean surface, and the toasted bread smell clearly turns into coffee aroma, which can be defined as the prelude to first crack. At this time, listen clearly for the sound of the first crack point. First crack begins at 8 minutes 40 seconds. Keep the low firepower unchanged, open the airflow damper fully to 5 (discharge at this time), adjust the firepower to 40°C, and discharge at 191.3°C. (This belongs to light-medium roasting.)

First crack stage: open the airflow damper to maximum

The first crack stage is one of the stages in the coffee roasting process that requires the most caution and concentration. Because the coffee beans had been continuously heated before this, the moisture inside the beans had turned into water vapor.

Due to continued heating later, the water vapor inside the beans and the carbon dioxide produced by the Maillard reaction exert great pressure on the cellular structure of the beans. Eventually the pressure becomes too great and the beans cannot withstand it, causing the cellular structure of the coffee beans to rupture. Water vapor, carbon dioxide, and some other substances then burst out from inside the beans, indicating that first crack has begun. Therefore, first crack produces a large amount of smoke, and here the airflow damper should be opened to maximum.

How Front Street records roasting curves

The following uses the roasting curve of washed Yirgacheffe Gudingding as an example:

Front Street's roasting process is as follows:

Roaster: Yangjia 600g half direct fire

Charge amount: 300g

Turning point: 1 minute 28 seconds, 97.8°C

Yellowing point: 5 minutes, 149.1°C

First crack: 8 minutes 42 seconds, 138.8°C

Discharge: 1 minute 48 seconds, 193.5°C

Discharge at dense first crack

Roast level: light roast

Front Street cupping flavor 12 hours after roasting: citrus and black tea on entry, with cream, caramel, and almond finish as the temperature changes, obvious sweetness returning, and a clean, sweet taste.

What is the best time point for roasting coffee beans?

The best time point does not mean that if you discharge beans at exactly which minute and second, it proves that your roast level or quality is consistent. This also involves the characteristics of the green coffee beans themselves, the rate of temperature rise throughout the coffee bean roasting process, and so on.

So for this question, without considering other factors and judging only by the single roasting factor of discharge time, it can be done as follows (this is a simplified version, assuming you already understand the green bean characteristics, the turning point is normal, and factors such as firepower are fixed):

Step One: Make assumptions

Based on your usual roasting experience, make a rough roasting prediction. For example, generally speaking, approximately:

When does first crack begin?

How long will first crack last?

How long is it from first crack to second crack?

Step Two: Sampling

At 30s, 50s, and 60s after the start of first crack, at 25%/50%/75% of the period between first crack and second crack, before second crack begins, when second crack begins, and upon entering second crack, take 11g samples each time.

Step Three: Cupping

Cup the sampled samples and determine which interval range best meets your expectations, and then you can make the judgment.

But for the same bean, different roasting paces will greatly affect the coffee's taste, mouthfeel, and flavor profile. The coffee roasting process is generally divided into three stages: the dehydration stage before the beans turn yellow, the browning reaction stage after yellowing when the main chemical reactions (mainly the Maillard reaction) begin until before first crack, and the development stage after first crack until the end of roasting.

Adjusting the roasting pace means adjusting the time and temperature rise of these three stages, as well as the temperature at the turning point.

Generally speaking

Coffee with a faster pace and shorter overall roasting time will have a lighter mouthfeel, lower complexity, bright acidity, and lively flavors. However, too fast a roasting pace can easily leave the coffee with vegetal green flavors and underdeveloped tastes.

Coffee with a slower pace and longer overall roasting time will have a heavier mouthfeel, higher complexity, and more caramel-chocolate tones. However, too slow a roasting pace will cause dull flavors, flat acidity, and lower coffee cleanliness.

Coffee roasting is generally divided into three stages, so how does adjusting the time of these three stages affect the taste of coffee?

In the dehydration stage, a fast pace will create higher pressure inside the coffee, lower mouthfeel, and higher cleanliness. A slow pace will allow less pressure to accumulate inside the coffee, give higher mouthfeel, and may make the coffee's flavor dull, with lower cleanliness and higher complexity. This is because a dehydration pace from slow to fast will make the beans accumulate thermal momentum and internal pressure from small to large in the early stage of coffee roasting.

This directly affects the pace of the latter two roasting stages. Greater pressure in the bean core is unfavorable to the Maillard reaction, causing fewer substances that bring Body to coffee to be produced, and instead preserving more floral and fruity aroma substances. The greater the thermal momentum accumulated in the early stage, the more it will also accelerate the pace of the later process.

In the stage after yellowing, the Maillard reaction begins. Shortening this stage and speeding up the pace will reduce the complexity of the coffee's taste, improve cleanliness, and make the mouthfeel lighter. Conversely, slowing down this stage will increase the complexity of the coffee's taste and give it a heavier mouthfeel, but cleanliness will decrease. The longer this stage is, the more caramel tones the coffee will have, and the coffee's taste will also develop toward depth and singularity.

In the development stage, from after first crack to the end of roasting. At this time, in addition to the continued occurrence of the Maillard reaction, the caramelization reaction also starts simultaneously. A fast-paced development stage will give the coffee lively, bright acidity, lower complexity, lower bitterness, and more variable aroma.

Slowing down the pace of the development stage may make the coffee flavor monotonous and uninteresting, but it will make the acidity rounder and give decent complexity. If dragged out too long, it may turn round acidity into flat, uninteresting acidity. Prolonging development time will also produce more chocolate and cream flavors.

Finally, Front Street Coffee will share "What conditions should a good coffee roaster possess?"

1. Green coffee bean identification ability:

At the most basic level, one must identify green beans from major producing regions by appearance and characteristics, understand the differences between new and old beans, judge and screen defective beans, and even know how to look up information on the source of green beans. All of this is in order to obtain stable quality when purchasing green beans.

2. Coffee roasting technical ability:

The education and training that machine vendors should provide includes functional operation, troubleshooting, and cleaning and maintenance of coffee roasting equipment. It also provides practical operation, such as the differences caused by different characteristics such as moisture content and hardness of green beans from major producing regions at the same roast level, the roasting curves and techniques that need attention, and control of airflow damper, temperature, and firepower at different roast levels.

3. Coffee cupping and blending ability:

Basic cupping practice allows the roaster to judge whether coffee quality is good or bad, as well as the quality of roasting completion. In terms of the ability to describe coffee flavor, it can also strengthen explanations for sales introductions to customers. In addition, when blending the house blend used in the store, one can better grasp the characteristics that a single coffee is meant to express, balance and coordinate various proportions, and showcase the unique taste of a café that roasts its own coffee.

In short, coffee roasting presents all kinds of difficulties. Only by becoming familiar with the principles of coffee roasting, continuously accumulating experience, and adapting on the spot can a barista master superb skills.

The above content is compiled by CoffeeHunters, a coffee news website.