Coffee beans roasting technology machine introduction

Beginner's general knowledge-introduction to coffee bean baking machine

A series of chemical changes occur in the process of baking. After about 15 minutes of baking, green

Coffee beans lose humidity, turn yellow, and then burst, just like popcorn. After this process, the coffee beans will double in size and begin to show a light brown after stir-frying. After this stage is completed (after about 8 minutes of baking), the calories will be reduced. The color of the coffee soon changed to dark. When the preset baking degree is reached, cold air can be used to stop baking to achieve rapid cooling. The most suitable baking degree varies depending on the type of coffee beans. Someone asked me how to find the most suitable baking degree. My answer is "can only be inferred in my own way", and I must also learn the "basic baking" learning program. The learning method is to roughly fry coffee beans from Cuba or Ethiopia to Italian deep-roasting (Italian Roast), test the taste at the prescribed baking stage and keep it in mind.

At first, it can be divided into four stages: shallow baking, moderate baking, medium-depth baking and deep baking. After the habit, there are 8 stages, 16 stages, and sometimes subdivided into 24 stages and 32 stages, which are confirmed by cup testing as the taste changes from very shallow baking (Light Roast) to very deep baking. This is the "basic roasting" of Baja Coffee, a coffee shop opened by Taguchi in Japan.

The secret of baking: get the highest caramel and least carbonization. Caramelization is a link that has the greatest impact on the flavor of coffee. After six to seven minutes of baking, raw beans absorb a lot of heat and start the pyrolysis reaction, resulting in the first explosive sound. Some sugars are converted into carbon dioxide, and water continues to evaporate. New aromatic components gradually develop into the so-called coffee oil. And combine with hundreds of aromatic substances such as nicotinic acid, citric acid, quinic acid, malic acid, acetic acid, caffeine and so on. Pyrolysis reaction can continue to the second explosion, although caramelization is an important process to awaken aromatic elves, but with the extension of baking time, some ingredients will also be carbonized to form a bad astringent bitter substance, how to obtain the highest caramelization, but also to minimize carbonization, which seems to be contradictory, but it is the biggest challenge for bakers.

Pay attention to the changes in sound, color and taste. The above chemical reactions can be judged by listening to the sound, seeing the color and smelling the smell. As the color of coffee beans continues to heat up, the color of coffee beans will change from gray to golden yellow to light brown, then to a trace of reddish brown of oil, and then a large amount of oil will show a dark brown of oil. if it goes on baking, the coffee oil on the bean surface will become dry and dead black. and emit a lot of blue smoke, sandwiched with a scorching smell, this is a warning that is close to the burning point. Prepare to call 119 to help put out the fire. Experienced bakers will choose between light brown to oily dark brown for safety. Coffee beans change from shallow to deep because of changes in caramelization and acidity.

Listening to sound is also the basis for judging the degree of baking. If the temperature of the roaster is hot enough, coffee beans will burst twice during the roasting process. For example, high-temperature-resistant raw beans such as Mantenin and Angelica will burst for the first time in about seven minutes, and the sound will be low and sparse. This means that the "pyrolysis" is started, that is, the starch begins to be converted into caramel, and water is ejected from the bean surface with carbon dioxide, making a low burst sound, which is quiet for two minutes. At about 12 minutes, there was a more violent and sharp burst, which was the sound of broken fibers in coffee beans, which indicated that the baking was coming to an end, and the fragrance would fade if it went on. We can see that coffee beans can talk.