Common sense of coffee roaster used in coffee shop

Coffee shop bean dryers, retail bean dryers, and small bean dryers are all medium to small bean dryers, which are often used in coffee shops during wartime. Before the early 20th century, most of their coffee beans were made by bean roasters in such cafes, as long as they were not baked at home, but by the early 1950s, large baking plants and pre-ground packaged coffee beans were popular. By the end of the 20th century, when coffee shops were making a comeback with bean roasters, consumers in the United States and other industrialized countries rediscovered the joy of carefully roasted fresh coffee beans.

Eighteenth century: bean dryers used in American cafes

This bean roaster was probably used in the cafe at that time. This bean dryer is an improved version of the bean dryer for household cylindrical fireplaces in the 17th and 18th centuries. it is also a very simple structural design. The whole bean dryer must be placed in the fireplace and placed on the residual fire, while turning the cylinder by hand.

Eighteenth century: bean dryers used in British cafes

The bean dryer in the picture has two more improvements to the design of the fireplace bean dryer:

1. The bean dryer itself has a built-in heating source, and coal can be burned at the bottom of the drum to provide heat energy.

two。 A cover is added to the drum of the bean dryer, so that the heat energy inside the drum can be distributed more evenly.

1862: bean dryers in cafes in the United States

The design, first made in 1862 by E.J.Hyde of Philadelphia, was a typical design of a bean dryer in an advanced caf é in the mid-19th century. This bean roaster is designed to pull the baking drum out of the fire to facilitate the cooling of the roasted coffee beans. In addition, a mixing blade is designed inside the drum, which can promote the rolling transposition of coffee beans when rotating the drum. In this era, the heat source of the bean dryer is still built-in coal fire at the bottom of the drum, and the drum is still rocked by hand.

1890s: French gas fire bean baking machine

According to coffee historian William William Ukers, the world's first patented gas coffee roaster was first seen in France in 1877. Until today, roasted coffee beans from gas sources are still the mainstream all over the world. The Watts-fire bean roaster in the picture was patented by M.Postulart in 1888. The baking chamber was still spherical in part. At that time, Germany, Britain and the United States had already taken guns to the round-shaped bakery. France is the only country that is still loyal to the spherical bakery. The roasted coffee beans are poured out of the spherical baking chamber by the principle of gravity and entered into the lower drum cooler through a loophole. After cooling, they are poured directly into the bottom drawer.

1907: bean dryers are used in German cafes

In the picture of this Perfekt bean dryer made in Germany in the early 20th century, the pulley drive belt on the left side of the outside of the machine is the structure that drives the rotation of the drum, and it is also through some gear structures (which can only be seen clearly from the right side of the bottom) to indirectly drive the mixing blades in the cooling plate. The function of the stirring blade is to stir the coffee beans and improve the cooling efficiency.

The heat source of this bean baking machine is gas fire, and there is an exhaust pump at the base of the machine, driven by a belt on the left side of the outside of the machine, which blows heated air into the baking drum to circulate, thus ensuring a more uniform baking result. and effectively shorten the batch baking time, not as time-consuming as the old bean baking machine which only relied on heat conduction. This hot air stream also plays the role of bringing out the baking smoke and silver skin (a layer of film attached to raw coffee beans); finally, there is also an exhaust pump blowing fresh cold air at the bottom of the empty cooling plate, which works with the mixing blades in the cooling plate, the cooling efficiency is greatly improved.

In such a bean roaster, the tool to detect the baking depth is to make a small hole in the front of the roaster and insert a long "Trier". The sampling rod can go deep into the coffee bean pile in the baking process to obtain a small number of coffee bean samples. The coloring depth of these samples is the basis for the roaster to judge the timing of the beans. Once the roaster decides it is time to drop the beans, the roaster can pull up a lever and press it. Open the bean mouth, and the roasted coffee beans can be poured out to the cooling plate.

Although there were new electronic devices and many improvements in roasting technology in the 20th century, this bean roaster and other similar machines remained the mainstream of small-scale coffee roasting throughout the 20th century.

Early 20th century: bean dryers for German-made small cafes

In Germany and other European countries in the 1920 and 1930s, streamlined, space-free bean dryers like the one pictured here are often displayed by cafes on the front door or windowsill, and attract the attention of passers-by with the smell of baking. The working principle of this bean baking machine is almost identical to that of the aforementioned machine.

1980s: bean dryer for airflow cafes (internal section)

The air-flow bean roaster heats the coffee beans with the same hot air flow and stirs the coffee beans at the same time (let the coffee beans move in the way of gas). In the air-flow baking model designed by American Mike Siewicz, the heated hot air is blown from bottom to top through the sieve at the bottom of the baking chamber, which can drive the coffee beans up along the wall of the baking chamber and fall down at the top. Then there is a fountain cycle over and over again, and the position of the temperature probe part of the thermocouple thermometer can roughly measure the temperature of the coffee bean pile in the baking room. it is easy for the roaster to judge the timing of the beans according to the temperature point rather than the apparent chromaticity. The roasted coffee beans will be directed to another separate cooling chamber and cooled with cold air at room temperature.

In the past 50 years, there have been many other types of air-flow bean dryers, whose basic structure and working principle are more or less the same, only when coffee beans are stirred in the hot air flow mode. many air-flow bean dryers have added bean viewing windows or changed to use glass tubes as baking rooms, adding some interest to the originally ordinary foreign trade. On the other hand, the small air-flow bean baking machine even brings the automatic control technology into the baking control, so that the bean baking machine can be guided by electronic devices after the thermocouple thermometer reaches the preset target temperature value. automatically cut off the power to the heating part of the baking.