The way coffee is roasted

Why do coffee beans need to be roasted?

Coffee will be fascinated by people, the key lies in the aroma formed after baking and the taste and flavor when drinking. The taste of raw coffee beans is described as the smell of soil or grass, but baking is like magic, which completely changes and reorganizes the internal substances of raw coffee beans to form a new structure and form a strong and mellow flavor. It can be seen that roasting shapes the soul of coffee.

What is the common way of baking?

What kind of appliances do you have for each baking method?

The roaster is mainly divided into three types: direct fire type, semi-hot air direct fire type and hot air type.

1. Direct fire type

Direct fire is the earliest baking tool, that is, raw beans are roasted in a hot drum and then transferred to the cylinder. The built-in motor keeps running the drum and stirring the coffee beans in the drum, trying to make each coffee bean come into contact with the hot iron evenly to achieve the goal of balanced roasting.

Disadvantages:

The thermal conductivity of ● metal is not fast enough and it takes more time to complete baking.

● burns the outside of the drum; however, the heat dissipates in the air, so it is a pity that it cannot be put to good use.

● 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.

The silver film or silver skin produced by ● during baking will be left in the tube, which is easy to attach to the surface of coffee beans and make the flavor cloudy.

two。 Semi-hot air direct fire type

Between 1870 and 1920, the German Van Guban Van Gulpen devoted his whole life to the improvement and manufacture of drum roasters, thus leaving many ideas for posterity, in one of his inventions, coffee beans were 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 a heat source, but Derek Diedrich, of Idaho, Idaho, took the lead in using gas-activated infrared heat source Gas-Infrared in 1987 to make temperature control more accurate, well received and become the first brand in North America.

Today's drum-type 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, which can not only increase the heating rate, but also blow away the detritus, so as to produce balanced and clean coffee beans.

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

3. Hot air type

In the 20th century, some people thought of using hot air to bake coffee beans. In addition to using hot air to bake coffee beans without iron barrier, the heat source can be transmitted directly to raw beans to improve baking efficiency.

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

In addition, the wind bed roaster Fluid-Bed Roaster can still be seen in the market. Here can be briefly introduced: the structure of the hot air baking machine still adopts the drum design; the raw beans are turned by rolling to achieve balanced baking. However, some people have long thought why not use hot air to move raw beans, so that beans can float up and down, breaking the concept of rollers.

In 1976, American Michael Schweitz Michael Sivetz designed the wind bed roaster Fluid-Bed Roaste, which allows air to blow up and down in an airtight container, so that raw beans can float up and down in the container, and then pour into the cooling tray outside the container to cool it until the baking is finished. Michael Schweitz's comments can often be seen on the website of the selected Coffee Association of the United States.

There are similar baking methods of design and construction in Australia; Roller Roaster, a roaster created by Iomberstein Ian Bersten and marketed in Australia, is also well known. In the general baking process; the water in the beans is evaporated less and less, and the quality becomes lighter and lighter, so the weight of the roaster will fall faster and accept the hot air baking again, so repeatedly, that is, the coffee beans can be baked evenly, but without the smoldering of the metal drum, some people will think that there is always one less taste.