What are the best roasting methods for coffee? The difference between direct fire, semi-hot air direct fire and hot air

Roasting method of ◎ selected Coffee

Coffee will be fascinated and loved by people, the key lies in the aroma formed after baking and the taste and flavor of drinking. Coffee raw beans themselves do not have any special taste, but "baking" is like magic. The substances inside the raw coffee beans are completely transformed and reorganized to form a new structure, with a strong and mellow flavor, becoming the burning coal of the human mind.

The discovery of ◎ baking

Ethiopians were the first to discover coffee, but at first they only knew how to chew seeds and leaves. Around the early 13th century, Shazri Al-Shabhili, a Muslim hermit, is said to have discovered the way of roasting, roasted and ground coffee beans into powder, making man's first cup of coffee.

Shazri belongs to the Sufi of the Sufi sect of Islam. He studied hard from an early age, but became blind. He once lived in exile in Egypt and made Hajj pilgrimages to various Muslim holy places, but died on the way.

His followers also practised asceticism in the Arabian Peninsula as a mendicant monk, so coffee spread unwittingly.

And those ascetic monks have been to Spain as far away as Spain, where there is still an Al-Shabhiliyah in Algeria to order a cup of Shazri, which means to order a cup of coffee.

It is almost universally accepted that coffee roasting was first found to belong to Arabs, and hence the existence of Shazri legends. However, some people may think that this may be an inadvertent discovery. It is said that in ancient times, farmers in Yemen or Ethiopia cut off coffee branches and burned them as firewood while cooking food. In this way, they inadvertently found that the roasted coffee beans emitted a strange fragrance. After careful attention and follow-up development, they gradually became the prototype of today's coffee roasting. So the discovery of coffee is only by accident, which has been accepted by many coffee historians.

The tool of ◎ baking-roaster

Commercial roasters are mainly divided into three categories:

(1) Direct fire type

(2) semi-hot air direct fire type

(3) Hot air type

At present, the application of semi-hot air direct fire type and hot air type is the best, which is often the mainstream in the selected coffee market.

(1) Direct fire type

The earliest baking tool used by human beings is the direct fire type, that is, the raw beans are roasted by fire and then transferred to the drum. Although the motor keeps running the drum and stirring the coffee beans in the drum, in an attempt to let each coffee bean come into contact with the hot iron evenly, to achieve the goal of balanced baking, this baking method always has some disadvantages.

The disadvantages are as follows:

The heat conduction rate of ● iron is not fast enough and it must take more time to complete baking.

● burns the outside of the drum, but the heat dissipates in the air, so it's a pity that it can't be used properly.

● when the raw bean touches the inner wall of the drum for too long, it is easy to scorch, resulting in bitterness and scorching taste.

There are a lot of detritus (silver film or silver skin) produced during ● baking, and the contents left in the tube are easy to adhere to the surface of coffee beans, which will also make the flavor cloudy.

(2) semi-hot air direct fire type

Between 1870 and 1920, the German Fan Guban Van Gulpen devoted his whole life to the improvement and construction of drum roasters, which left a lot of ideas for future generations. In one of his inventions, coffee beans have been promoted to be brought into baking with hot air.

The Perfekt roaster made in Germany in 1907 began to introduce this concept. It uses gas for heating, and there is an air pump that brings half of the hot air into the drum and the other half to the outer barbecue drum. At present, German drum baking still has some reviews in the industry.

On the other hand, the German Boroba Probat drum roaster can be said to be spread to the baking industry all over the world.

Generally speaking, roasters use gas or electricity as heat source, but Derek Diedrich Company of Idaho, Idaho, in 1987, took the lead in using gas-activated infrared heat source Gas-Infrared to make temperature control more accurate, well received and become the first brand in North America.

Today's drum roasters almost all use semi-hot air direct fire type, on the one hand directly barbecue the hot drum with fire source, on the other hand bring hot air into the drum, blow into the hot air in the drum, can increase the heating rate, but also blow away the debris, and thus produce balanced and dry coffee beans.

However, due to the different structural design, and each boasts the best design, in fact, it is most important to understand the roasting of coffee. Roasters of the same grade and different brands will not cause much difference.

(3) Hot air type

In the past, human beings used to cook food directly by direct fire, so it was taken for granted that coffee was roasted directly by fire. in the 20th century, some people thought of roasting coffee beans with hot air without iron barrier. Heat source can be passed directly to raw beans to improve baking efficiency.

The Thermonro roaster Jadez Burns Thermalo made by Burns Company of the United States in 1934 is a kind of hot air type. There are still some large baking plants in the United States and are still using this kind of roaster.