What are the different baking stages in the baking process and how does baking need to be adjusted?

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Talk about baking in front of the street coffee. Raw coffee beans are tasteless and difficult to grind into powder. If your blender is of high quality and pulls the raw beans into powder and boils them into a drink (that kind of thing really can't be called coffee), it will only taste thin, light, grassy, and seem to have a little sour taste. I advise you not to bother.

The entire treasure of raw coffee beans is protected by its highly organized and dense reserves of fat, acids and sugars, and the key to the treasure is baking. The coffee oil of raw coffee beans is tightly wrapped in its cell wall and is roasted before it is transformed into flavored particles. Without baking, the real soluble properties of coffee beans cannot be realized. Maybe there is something wrong with the word "real", because the baking journey that embodies the full meaning of coffee beans does not end in a fixed way.

The primary goal of roasting is to heat the coffee to the desired ripeness, and then make further roasting adjustments according to the expected brewing method of the particular coffee or beans themselves. Shallow roasting can better show the natural flavor of coffee (good or bad), which is better matched with the relatively traditional brewing method. The partial depth of roasting replaces most of the original flavor of coffee with the coking roasting flavor that we are very familiar with, so the coffee beans of lower quality are almost treated by deep roasting. Deep roasting is suitable for making espresso at home (or cafe), and the basic characteristics of coffee brewing determine that the lighter the roast, the more sour the coffee.

The secondary goal of baking is to carefully control the development of coffee beans-to be honest, this is as important as the primary goal. According to the most popular belief, if the baking time or cooling time is too long, the brewed coffee will have a faint "baking" taste; if the roasting time is too short or the temperature is too high, the original taste of coffee beans may not be released in time. Coffee is prone to sudden sour, bitter and smoke taste.

Different baking stages

There are many critical stages in roasting, and how fast a serving of coffee beans goes through each stage is commonly known as the baking mode (roast profile). Many bakers write down each baking record carefully so that each baking can be reproduced with a small temperature and time error.

The first stage: removing moisture.

Coffee beans contain 7%-11% moisture, which is evenly distributed in the compact structure of the whole coffee bean. when there is more water, the coffee beans will not turn brown. This is the same as browning food when cooking.

After the coffee beans are poured into the dryer, it takes some time for the coffee beans to absorb enough calories to evaporate the excess water, so a lot of calories are needed at this stage. There was no significant change in the appearance and smell of the coffee beans in the first few minutes.

The second stage: turning yellow

After the excess water is taken out of the coffee beans, the first stage of browning begins. The structure of coffee beans at this stage is still very tight and has aromas similar to Indian rice and toast. Soon, the coffee beans begin to swell, the silver skin on the surface begins to fall off, and the exhaust device of the bean dryer is discharged into the silver skin collection bucket, which will be removed elsewhere to avoid causing a fire.

The first two stages are very important: for example, if the moisture of raw coffee beans is not properly removed, the subsequent baking stage will not be able to achieve uniform baking. Even if the coffee bean looks fine on the outside, it may be undercooked on the inside, and the cooked flavor is very unpleasant, with the bitter taste of the coffee bean surface and the undeveloped sharp sour and grass flavor of the bean core. After this stage, it is difficult to save even if you slow down the baking rate, because different parts of the same bean will develop at different rates.

The third stage: the first explosion

When browning begins to accelerate, coffee beans begin to produce large amounts of gas (mostly carbon dioxide) and water vapor. When the internal pressure increases too much, the coffee beans begin to burst, make a crisp sound, and expand nearly twice as much. From then on, the flavor of coffee as we know it began to develop, and the bean baker could choose when to finish baking.

The bean baker will find that if given the same firepower, the temperature rise will slow down, and if the heat energy is too low, it may cause the baking temperature to stagnate and cause the coffee flavor to be dull.

The fourth stage: flavor development stage

After the first explosion, the coffee bean noodles will look smoother, but there will still be a few wrinkles. This stage determines the final depth of coffee coloring and the actual depth of roasting. The baker has to handle the sour and bitter taste of the final cooked bean product. The longer the coffee is roasted, the higher the bitter taste.

Stage 5: the second explosion

At this stage, the coffee beans burst again, but the sound was more subtle and denser. Once the coffee beans are roasted to the second explosion, the internal oil is more likely to be brought to the bean surface, and most of the sour taste will fade and produce a new flavor, often referred to as "baking flavor". This flavor does not vary according to the type of beans, because it is caused by carbonization or coking rather than internal flavor components.

Roasting coffee beans deeper than the second stage is dangerous and can sometimes lead to fires, especially when using large commercial bean dryers.

In the field of coffee roasting, there are baking depths such as "French roasting" and "Italian roasting", which refer to coffee beans roasted to a very deep depth, with a typical high concentration and high bitterness, but the personality of most beans will disappear. Even though many people like the flavor of heavily roasted coffee, if you want to know the flavor and personality of high-quality coffee from different places, it is recommended not to choose heavily roasted beans.