Coffee roasting: The secret ingredient of a good cup
As you will see, the coffee is cooked three times. The first step begins from collection and storage. Secondly, we proceed to coffee roasting and finally there is the preparation. Although each of the stages plays an important role, roasting is the one that will define the preparation method and the quality of our cup.
Coffee roasting is a physical-chemical procedure. Where the initial characteristics of the green beans are altered when producing other components. That is, the acidity, the balance of flavor and body, the latter will depend on the preferences of the roaster and of course, those of the client,
In Incapto Coffee, before reaching the roasting or toasting stage, some samples are evaluated. We then select the coffee that we think will be liked by our clientele. Subsequently, we make a forecast and bring the bags to the company facilities. Incapto Coffee To avoid poor conservation, we opt for packaged or “gaipro” bags, which are special packaging that helps preserve these products for longer. Then they will be put inside a jute one.
That being said, it's time to get down to business. In this article, you will be in charge of explaining in detail everything related to coffee roasting, from the types, characteristics and which ones best fit each preparation method.
What is coffee roasting?
As we have explained above, the coffee roasting, is one of the most important steps. It will even influence the final result of our drink. This without leaving aside the variety, origin, height, processing process, grinding, among others.
Coffee roasting is based on apply heat to green beans. To do this, toasting machines are used, which are responsible for providing those shades that range from cinnamon to darker. Thanks to this process, organoleptic properties are developed, that is, the aroma or flavor. Qualities that make a cup much more vibrant. It should be noted that coffee roasting begins with drying the moisture of the bean, which is approximately 12%.
Through this, pyrolysis reactions occur, which is the thermal decomposition of the raw material in the absence of oxygen. Something very common in heat and matter transfer processes. This gives rise to important physical changes in the grains. As well as the appearance of the substances responsible for the sensory qualities of coffee.
During the procedure, the grains gain a total of 100% volume. While reducing between 12 and 20% of its weight. It also loses 10% of its caffeine. A decrease in its acids and a slight increase in fats is detected.
Coffee roasting curves
In the process of coffee roasting, two variables are handled, which are temperature and time. Thanks to these, you can achieve various types of roasting, using the same beans. In addition to graphing the curves of said procedure, this can tell us the qualities of our cup.
It should be noted that, to make a roasting curve or profile, it is necessary to record the temperatures recorded at fixed time intervals. Until you get the final product.
They will also need other data like:
- Humidity percentage
- Coffee variety
- Density
- Initial and final weight
- Agstron scale number
- Origin
- Losses
The roasting curves are specific instructions from the master roaster. As you will see, this practice seeks to transform green coffee into roasted coffee. The professional aims to find the quality and a particular precision of the brand.
What does coffee roasting time influence?
Roasting time ranges between 12 and 25 minutes. Something that will depend on the roaster, consumption habits in that country and even if the roast is single-varietal or blend. Another factor that will also be taken into account is whether the coffee will be used for hospitality or food.
Experts warn that roasting at short notice is not advisable. Due to the speed of roasting, and the difficulty of controlling the process. Just as it is not advisable to subject the beans to longer periods of time in the roaster. Since, the volatile compounds would be lost. The reason is because the volatile compounds would disappear.
The resulting grain has greater volume, fat content, acids, extracts and moisture. It also increases its extraction capacity, if it is used to produce soluble coffee.
Coffee roasting levels
Before getting into the matter, we want to highlight that the color of the roast continues to be a topic of debate. The beans once placed inside the roasting machine will change their green appearance. In short, it will adopt brown tones whose intensity (light or dark) will be defined by the master roaster. It should be noted that everything will depend on the preferences of each country, and even the palate of each consumer.
Therefore, the degree of coffee roasting is generally classified into three types, which are:
Light roast
They are characterized by retaining more of the flavors of the grain. They provide a cup of coffee with notes floral and fruity. Within the Agtron scale it is between 75 and 95. If we talk about its tone, it tends to be cinnamon.
Among its other organoleptic properties, light roasts, it has a low body, high acidity and there are no obvious roasted flavors.
medium roast
They are between 55 and 65 on the Agtron scale. Its shade is a regular brown. After spending a few minutes in the machine, the roast reaches this state. Being the favorite of specialty coffee sellers in the United States.
This type of roast is often used to prepare espressos. It is because it has greater sweetness and body. There is also a balance in terms of acidity, aroma and complexity.
dark roast
On the Agtron scale they are between 25 and 42. As you spend more time in the roasting machine, the coffee begins to ring again. The oil begins to emerge. This state is called second crack.
In relation to its organoleptic properties, it tends to be a little spicy. However, it loses complexity, but gains a more pronounced body. The aromas and flavors of roasting become much more evident. As if that were not enough, they can resemble chocolate and nuts.
But if it is extra dark, the drink can become bitter. Which would prevent us from recognizing some of the inherent characteristics of the grain.
How do we carry out the roasting process in Incapto Coffee?
On any given manufacturing day, The first thing we do is preheat the toaster machine. Subsequently, we plan which coffees we have in roasted stock. Then we weigh the amount that will be placed in each toaster, in separate buckets, and multiply it by 1.2. The reason for this is because the beans lose between 15 and 20% of weight during roasting after evaporating a large part of the moisture.
Depending on the type of coffee, we will use more or less quantity. For example, if we decide on the Brasil Fazendas, we place 21 kg, while the size or weight of each Sumatra load is 19 Kg.
Now, once we have all the grains weighed, We will analyze the humidity and density.
Both variables They will help us determine the roasting profile. That is, those coffees that have higher humidity will generally have to be subjected to high inlet temperatures or higher gas power, since they contain more water inside, which must evaporate.
But if the opposite is the case, and the beans have little moisture, the flame power must be lower to toast it.
Another parameter that we can change depending on the type of coffee is the speed of the drum. In short, they are the turns that will be made per minute. Involving the inlet temperature, air settings and flame power during roasting. We can also determine the tone of the beans throughout the roasting process. A decision that will influence the final result.
In case you didn't know, Incapto Coffee, use an application called “cropster”. With it we can register information about each of the roasts that we are doing. On the other hand, we have three thermocouples located in three different places on the machine and connected to the computer. This is how we achieve collect time and temperature data, just like the roasting curve.
What are thermocouples?
It is about thermometers that collect the temperature of the machine. As we indicated above, Incapto coffee It has three of them, one in the position closest to the grain. It turns out to be very precise and with which we can guide ourselves perfectly when proceeding with the roasting.
If the diameter is smaller than the rest, it will help you find the temperature reading quickly and reliably. It is also used to record the temperature inside the drum., which means it has less contact with the grains. This being additional information.
After placing the toaster at the appropriate temperature, we proceed to toast the first batch. As in the small machine, Coffee is subjected to several phases during roasting.
We start with dehydration, at this point, the moisture evaporates. From approximately 150°, we will begin to notice color changes, this is due to the Maillard reaction. From this moment is when the sugars of the coffee bean are transformed and caramelized. When they are at 190°, the first crack occurs, which is when the coffee makes its first expansion.
The development time is what will define what we want to achieve with our coffee. In short, it is about the degree of roasting, whether we want it light or medium. We can even decide whether to highlight or reduce the acids, or simply whether it has more or less body.
To be more brief with this topic, the first thing you should know is that During the roasting process, coffee goes through a series of physical changes..
Starting with weight loss (15 and 20%), an increase in volume (100 and 130%) and its color change, which goes from green to brown. Without overlooking the chemical changes, such as the transformation into coffee's own sugars and acids. In fact, they are responsible for more than 700 new aromatic compounds, responsible for the aromas and flavors of roasted coffee.
