The meaning of coffee bean roasting and the common types of coffee bean roaster

The so-called coffee roasting refers to the heating of raw beans to promote a series of physical and chemical reactions inside and outside of coffee beans, and in this process to produce a variety of sour, bitter, sweet and other flavors of coffee, forming mellowness and tone, and converting raw beans into dark brown beans.

Among the factors that affect the taste of a cup of coffee, raw beans account for 60%, roasting accounts for 30%, and extraction accounts for 10%. Good baking can maximize the personality of raw beans and minimize the occurrence of defective flavor, while improper baking will completely destroy good beans. Due to heating in the baking process, time, temperature control is very difficult to grasp, baking technology is a very complex technology, so the importance of baking appears to be more prominent!

There are three common types of roaster, namely, hot air type, direct fire type, and semi-direct fire semi-hot air type.

1, hot air type roaster: the hot air type roaster uses the blower to absorb the air, raises the temperature of the air through a heating coil, and uses hot air as the heating source to bake coffee beans. hot air can not only provide the temperature needed for baking, but also use the power of airflow to stir coffee beans and kill two birds with one stone. Now there is a professional hot air roaster on the market, which combines the electric tumbling baking chamber with heat flow to make the coffee beans heated more evenly.

Advantages: high thermal efficiency, fast heating, relatively uniform heating of raw beans, easy to control.

Disadvantages: because the heating efficiency is high, it is easy to lead to excessive heating, resulting in the bean raw "core" is the so-called entrainment, and the temperature rise is too high, it is easy to make the coffee caramelization reaction is not enough!

Taste characteristics: the acidity is obvious, the taste is relatively clean and simple, but the taste is not rich enough and lack of depth, and deep baking is easy to produce pungent smell!

2. Direct fire: as the name implies, direct fire is the use of flame to directly heat coffee beans. Up to now, in addition to the general flame (including gas furnace fire and charcoal fire), direct fire also includes infrared and electric heating pipes.

Advantages: the baking time is long, which makes the caramelization reaction more sufficient and the flavor more rich.

Disadvantages: it is easy to cause uneven baking, and if the heat is not well controlled, it is also easy to scorch coffee beans and form a scorched bitter taste.

Taste characteristics: sweet, bitter and sour flavor is deeper than hot air, mellow, smooth taste, but the dry aroma of coffee beans is weak, sometimes when the roast is light, the taste of coffee beans will produce a strong smell of grass!

3. Semi-direct fire and semi-hot air type: the baking method which combines the advantages of direct fire type and hot air type is the mainstream of commercial coffee machine at present.

Semi-direct-fire semi-hot air baking is actually similar to direct-fire baking, but because there are no holes in the outer wall of the baking container, the flame will not directly touch the coffee beans. In addition, ventilation and exhaust equipment should be added to transfer the hot air from the outside of the baking container into the baking room to improve baking efficiency. Another function of this ventilation device is to suck out the silver skin of coffee beans. Prevent the silver skin from burning due to high temperature to affect the taste of coffee beans.

This kind of roaster has the advantages and disadvantages of both hot air type and direct fire type, and its heating mode is changed by adjusting the speed of hot air and baking chamber. The bigger the hot air is, the faster the speed is, the closer it is to the hot air type, on the contrary, it is close to the direct fire type.

Taste characteristics: the overall coffee bean taste is relatively rich, mellow, dry and wet fragrance is distant, excellent performance on the characteristics of coffee producing area!