Innovative baking technology in the 20th century: the baking method using purely hot air flow

Innovative baking technology in the 20th century: the baking method using purely hot air flow

Of course, how could there be no innovative baking technology in this era of the 20th century? In the middle of the twentieth century, there were two major milestones in the evolution from direct and indirect fire baking to hot air baking.

In 1934, Garbeth Burns developed a prototype bean roaster called Thermalo, which applied heat to the walls of the baking drum and had little effect on the roasting of coffee beans, but roared through the baking room with a strong heat as the main heating medium. This arrangement allows us to bake coffee beans at a lower air temperature, because fast-moving air can take away the gas produced when roasting coffee beans and improve the efficiency of heating coffee beans. Proponents of this innovative technology have a saying: "lower air temperatures and relatively fast-moving gases burn off less flavor oils, so coffee beans baked with this technology can have a better aroma performance."

In addition, in the 1930s, there was a bean roaster that completely abandoned the baking drum structure, but still retained a strong hot air flow while roasting and stirring coffee beans. This type of air flow bean roaster works very similar to today's hot air popcorn machine: hot air can also make coffee beans tumble and bake at the same time. The word "air flow" comes from the fact that when this kind of bean dryer works, coffee beans tumble in the baking room as if they were the same fluid. The baking principle of the air-flow bean roaster is similar to that of the Thermalo bean roaster in Gabes Burns: the accelerated hot air makes the baking temperature relatively low and can complete a batch of baking in a shorter time, which theoretically takes away less flavor oil.

In the United States today, the most widely used air-flow bean dryer is the one developed by Michael Sivetz, a technician and author who has a profound influence on the American coffee industry. The air-flow bean dryer developed by Mr. Siviz works by blowing upward with a strong hot air below, while coffee beans flow up the vertical baking chamber wall, and then fall like a waterfall. In this way, it is constantly cycled and stirred to achieve uniform baking. You can see a picture of one of the Siviz bean dryers and related instructions in the picture on page 55 of this book.

In the past 50 years, many other air-flow baking devices with different structural designs have been developed and gradually popularized on the market. some only make a small change in the patented design of 50 years ago (that is, blowing the hot air from the bottom of the baking chamber to the baking room, blowing the coffee beans up, and finally falling naturally along the wall of the baking chamber). Others, such as the rolling roaster (Roller Roaster) designed by Australian Ian Berstein and the System 90 centrifugal force packed bed roaster (System 90 Centrifugal,Packed-bed Roaster) from Garbeth Burns, are excellent baking collimation after thinking carefully about the concept of row baking. In addition, there are some machines that "show the air-flow baking process" as a gimmick, where you can see the coffee beans tumbling upward in the glass baking room, which can attract the attention of customers. let them be interested in understanding the relationship between baking technology and delicacy. These new small stores use air-flow baking machines to simplify the construction of bean roasters, and the operation process is mainly automated as far as possible.