Basic knowledge about roasting of boutique coffee

one。 The meaning of baking 1. The definition of roasting so-called coffee roasting (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 hue, and converting raw beans into dark brown beans. two。 The importance of roasting in the factors affecting the taste of a cup of coffee, raw beans account for 60%, roasting accounts for 30%, and extraction accounts for 10%. Good roasting can maximize the personality of raw beans and minimize the occurrence of defective flavors. on the contrary, improper roasting will completely destroy good beans. As the heating, time, and temperature control in the baking process is very difficult to grasp, baking technology is a very complex technology, so the importance of baking is more prominent.

two。 The history of baking as early as the 13th century, the Arabs invented to put coffee beans in a pot, heat them and stir-fry them, then grind them into powder, and then brew coffee. The early Arabs liked to bake the beans shallowly and boil them with spices such as cardamom. Later, this method of stir-frying coffee spread to Syria, Turkey and Egypt, where it is customary to stir-fry coffee black, then grind it into powder, add sugar and boil it in water, then pour it into a small cup without precipitation and drink it with coffee grounds. After coffee was introduced into Europe in the 18th century, Europeans also used the Turkish style to stir-fry coffee until black. Later, because of geographical and cultural differences, Europe was divided into shallow baking schools dominated by Nordic, German, British and Scandinavian countries and deep baking schools dominated by southern Europe. The former usually bake the beans to city--full-city, while the latter generally bake them to the same depth as italy,french. Accordingly, the North American continent, which was later dominated by immigrants from northern Europe, also followed shallow baking, while Latin America, which was dominated by immigrants from southern Europe, was popular in baking. Until the mid-19th century, most of Europe used iron pots or ovens to bake beans at home, and later invented small roasters that use closed iron buckets instead of iron pans and put them on a fire to manually control, and can bake a few pounds of beans at the same time. Used by some coffee shops. With the advent of large baking machines in the mid-19th century, large quantities of baked beans became possible. After continuous innovation after the advent of large roasters, electronically controlled precision machines have appeared in the first half of the 20th century, and machines that can continuously bake 5000kg every hour have been developed. The emergence of large roasters has changed people's own baking habits. Buying packaged baked beans or coffee powder to cook directly at home facilitates the fast-paced life of modern people. By the 1960s, branded beans dominated the market. But there are also problems in mass roasting: ordinary raw beans, in order to maintain excessive shallow baking, lack of freshness caused by the lack of flavor, since the 1980s, a "boutique coffee movement" was launched in the United States. It advocates people to buy boutique raw beans, home baking, drink fresh coffee, pursue quality and taste, and home roasting begins to receive attention. At the same time, the pursuit of coffee quality also forces some big roasters to adopt higher quality beans to ensure the baking quality.

three。 In the early days of the development and evolution of roasters, people generally used iron pots to stir-fry coffee beans. After coffee was introduced into Europe, Europeans used Turkish iron-pot roasting beans on the one hand, and later invented hand-operated rotary roasting, which could bake several pounds of beans at the same time. Used by some coffee shops. In the 1860s, large roasters began to come out, and the use of blower to cool baked beans in 1867 gave birth to the development and innovation of large roasters. At the end of the 19th century, the advent of hot air roaster greatly improved the speed and efficiency of coffee roasting, making it possible to produce more in large quantities. In the 20th century, with the combination of roaster and electronic, it was improved to be more precise, and the fully automatic roaster appeared and had more advanced functions.

four。 At present, common roaster types and main brands (1) common roaster types 1. The hot air type bean dryer uses the blower to absorb the air, and then let the air raise its temperature through a heating coil, and use the hot air as the heating source to bake the coffee beans. hot air can not only provide the temperature needed for baking. you can also use the power of air to stir coffee beans and kill two birds with one stone. Advantages: high thermal efficiency, fast heating, relatively uniform heating of raw beans, easy to control. Disadvantages: because of the high heating efficiency, it is easy to lead to excessive heating, resulting in beans "entrainment", and too high temperature is easy to make the caramelization reaction is not sufficient. Taste characteristics: the acidity is obvious, the taste is relatively clean and simple, but the taste is not rich enough and lacks depth, and deep baking is easy to produce irritating taste. 2, the direct fire type, as the name implies, the direct fire type is to heat the coffee beans directly with a flame. Up to now, the "fire" of direct fire not only includes general flame (including gas furnace fire and charcoal fire), but also includes infrared and electric heating pipe. Advantages: long baking time, so that the caramelization reaction is more sufficient, the taste is more rich, disadvantages: easy to cause uneven baking, heat control is not good, but also easy to scorch coffee beans, forming a scorched bitter taste. 3. Semi-direct fire semi-hot air baking method, which combines the advantages of direct fire type and hot air type, is the mainstream of commercial baking machines at present. Semi-direct-fire 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, a ventilation device is added to introduce 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 exfoliated silver skin (the film attached to the outer layer of coffee seeds). Prevent the silver skin from burning because of high temperature in the baking room, thus affecting the taste of coffee beans. Semi-direct fire semi-hot air machine has the advantages and disadvantages of both direct fire type and hot air type, but its heating mode is changed according to the adjustment of hot air and boiler speed. The larger the hot air, the faster the speed is, the closer it is to the hot air type; on the contrary, the closer it is to the direct fire type. (2) main roaster brands 1. Germany's old probat brand, large, small and medium-sized machines, semi-automatic, full-automatic various types, sophisticated design, expensive. two。 Japan fuji-royal Japan fuji products, performance is also good, but the same price is not cheap (3) Coffee Mingjia roaster introduction 1kg semi-direct fire semi-hot air roaster, is a coffee machine produced by Korea Taihuan Company, although there is still a certain gap in performance with probat, but compared with its more affordable pricing, this machine is still good value for money, it has power heating type and gas heating type, with uniform heating High thermal efficiency performance, and its external game design is also very exquisite amplifier. Fifth, the reactions and changes occurred in the baking process. Drying: when the raw bean is heated, the water vapor in the raw bean will evaporate, and the raw bean will turn white from green at about 135 degrees Celsius. With heating, raw beans change from green to light yellow, and when the temperature reaches about 160 degrees, they give off the aroma of baked cereal. After continuous heating, the beans turn light brown. After an explosion of about 190 degrees dehydration is completed, the cell wall is ruptured due to internal thermal expansion, and a series of thermal decomposition reactions occur inside the beans, in which the caramelization will bring the sweetness, dark brown and mellowness of the coffee beans. the explosion lasts about a minute and a half. 4. With the progress of heating, the second explosion enters the "second explosion", and a more violent reaction will take place inside the bean. And give off a lot of heat. With the end of the second explosion, the raw bean has basically turned black, the bean body has expanded to 1.5 times that of the original, the surface is oily, and the weight is reduced to 12%, about 20%. 5. Stopping baking usually ends about a minute after the second explosion, when the temperature reaches 230 degrees, which will be deeper French or Italian baking, which may cause the coffee beans to ignite spontaneously when the temperature exceeds 230 degrees Celsius. six。 Baking degree division standard 1, roughly divided into shallow baking, medium baking, deep baking, re-baking four degrees. 2, each category can be subdivided into two categories, a total of eight kinds of shallow baking: Light light baking Cinema cinnamon baking: Medium moderate baking High medium deep baking: City city baking Full-city city baking seven. The technical difficulty of baking and bakers can change the taste of beans due to a variety of small changes in temperature and heat in the baking process, different beans have different characteristics, and baking is a work of rapid operation in a short time, so bakers are required to master the relevant principles, clearly grasp the characteristics of raw beans, and accurately budget and adjust the baking process in the baking process. In fact, because of the complexity and variability of the baking process, a real baker needs not only theory, but also a lot of experience and perception.