6 Common Mistakes That Roasters Make

Vietnamese Coffee Exporter


6 Common Mistakes That Roasters Make? There must have been a time when you, as a coffee drinker, felt that something was wrong with the coffee you were drinking. It’s fine if you don’t think you have acute senses. Because if you just stop at a questionable level, that means your coffee is still good and drinking.

And if it’s clear that all you want to do now is finish pouring the coffee, then… So, let’s go after the coffee flaw, particularly the roasters.

Here are 6 coffee roasting faults that you can spot during cupping, as the title says (or enjoying).



This is a common roasting blunder since it is so easy to make.

To distinguish a batch of baked coffee, first understand that you will not be able to notice it with your naked eye, but will only be able to feel it through the act of drinking or cupping.

The flavor and taste of baked coffee will be weak. It’s not the kind of pale we get when we dilute the coffee; it’s the kind of flavorlessness. When you drink, there is no discernible flavor; everything almost passes past your mouth in a bland and uninteresting manner, leaving no lasting impression. The coffee will have a dry cereal or bread aroma.

When the coffee beans take too long to achieve the temperature of 1st crack, this mistake occurs. Alternatively, the quantity of heat transmitted to the coffee beans may be quickly reduced throughout the roasting process.

In general, this is a mistake that occurs when the coffee beans are not given enough energy during the roasting process. To put it another way, coffee roasting is a set of physicochemical processes that take place on a regular basis. If the coffee beans are left too long, they will not only destroy the beneficial compounds that have been formed, but they will also be unable to go to the next step.

This could be due to low-quality green kernels, although this is doubtful because most roasters assure their clients that their ingredients are top-notch.


When cupping, you can detect if a batch of roasted coffee is undeveloped immediately away by looking at the crust. This is the layer of coffee powder that expands and covers the full surface of the cup when it comes into contact with hot water. The crust will not form or may be very weak, unable to retain its shape if the coffee is underdeveloped.

Coffee that has been cultivated improperly will have a vegetal flavor. It has a smokey aroma that reminds me of hay or straw. It’s like though you’re eating a raw pea.

One explanation for this is that the time it takes for coffee beans to caramelize and create flavor before and after 1st crack is too short.

Furthermore, cupping a batch of freshly roasted coffee makes crust development more difficult at a moment when CO2 is exiting at its fastest rate.

The problem can be solved by extending the seed development time after the first crack. However, if the development phase is prolonged too long, too much sugar will be burned, and the coffee will lose its sweetness.


Overdeveloped roasted coffee beans, in contrast to undeveloped coffee beans, are the result of an excessively long roasting time. Prepare for bitter flavors and the smell of burning smoke if you buy coffee bags with beans that are very dark (or black) and have an oily surface. Over-roasted coffee beans have this recognizable characteristic.

Some roasters will not consider this an error because they plan to roast dark for clients who want a super-black beverage. They may clarify that the consumer requires a strong coffee to avoid being overwhelmed by the condensed milk’s harsh sweetness.

That could be true from their perspective. However, professional roasters who utilize high-quality ingredients can readily pinpoint a moment when the beans have been roasted sufficiently and do not have such unpleasant flavors. It’s clear that they wouldn’t mind roasting to ruin the original good flavor of high-quality coffee beans for which they had to pay more money and exert more effort to obtain.

However, people who appreciate coffee are aware that it is roasted so darkly that only the smell of burning and bitter smoke can disguise all of the coffee beans’ flaws. The audience will be unable to distinguish between poor quality coffee beans, unripe ones, worms, damaged fruit, and old coffee that has been aged for a long period if this method is used.

These flawed beans will produce a poor cup of coffee and, more significantly, will be harmful to your health.


Without tasting, this inaccuracy can be detected with the naked eye. The coffee bean’s flat side with a surface scorch flaw will be blacker than the other. This is due to one side being forced against the drum for too long and receiving too much heat, while the other side receiving insufficient heat to continue developing.

As a result, roasted coffee beans with a burnt fault will have the flavor of both underdeveloped and overgrown bugs. When you drink coffee, you’ll notice that it smells like it’s burning, like ash with a bitter aftertaste, and that it smells like plants.

Lowering the charging temperature is critical to avoid burned coffee beans. Additionally, increase the drum’s rotation speed so that the beans do not remain in touch with the roasting drum’s surface for an extended period of time. However, if the roasting drum rotates too quickly, a considerable centrifugal force is generated, and the coffee beans are pushed so hard that they firmly press against the drum wall, resulting in the same error.



The black specks on the border of the bean are a sign of this fault in coffee beans. Batches of coffee that have been roasted to an extremely dark degree are prone to this mistake.

When it comes to taste, tipped coffee beans have a similar aroma as burned coffee beans. Negative flavors like smokey (smoke), burnt (burnt), ashy (ash), and bitter taste, on the other hand, will overpower all other flavors.

This is sometimes caused by an excessively high wind temperature early in the roasting process. It’s easy to grasp if you think about it this way:

The temperature differential between the coffee beans and the roasting drum is very large when starting to insert the coffee beans into the roasting drum. The coffee beans will enter the drying phase (Drying phase) at this time and will continue to absorb the heat from the roasting drum surface as well as the air temperature in the drum.

Coffee beans, in most cases, absorb heat slowly and evenly throughout the bean. The coffee beans will not be absorbed in time if the heat applied to the roasting drum is too high at this time.

As moisture escapes from the beans, it’s only logical for it to start escaping from the weakest structural sections first, which are the beans’ edges. Because they are exposed to too much heat in too short a time, these areas will quickly scorch.

To remedy this scenario, lower the temperature of the beans; do not roast the green coffee beans to the temperature of the second crack. Furthermore, early in the roasting process, it is feasible to slow down heat transfer from the wind, giving the beans more time to absorb and transfer heat.



In actuality, this is not a roasting error, but rather a mistake made during the classification and inspection of green kernels. However, in the specialty process, removing low-quality grain is certainly not a one-person task.

Common coffee roasting

The beans in a batch of coffee beans that are deficient in Quakers are substantially lighter in color than the rest of the roast. Simply squeeze the seeds with your hand to break them up; they have a papery smell that is sometimes evocative of cereal flours. These beans will make your coffee taste incredibly dry when consumed.

As a result, if you come across seeds that are substantially lighter in color, remove them right once.


Try drinking straight or cupping if possible, in addition to inspecting the appearance of newly obtained coffee beans. Because it’s whole grain, you’ll be able to see the flaw in the roast with your eyes. When the coffee is powdered, however, only your senses of taste and smell can alert you to the fact that anything is wrong with it.

The first batch of flawlessly roasted coffee will provide you with relaxation and enjoyment. Only then will we be able to talk about how tasty it is.

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