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The design mechanism of fluid bed bean dryer can be divided into two types as shown below.

Source: https://upload.wikimedia.org/wikipedia/en/a/af/Fluidized_Bed.jpg

One is the oblique air intake (left above), which uses the force of air flow to make the beans circulate in a fixed direction; the other is to design the baking tank into a cone shape (right above) and blow hot air into the center to allow the beans to circulate from the center to both sides. The structure on the right is the third prize in the 2018 Kaohsiung Dagang Cup Bakery Competition [WPM vertical full heat fan].

WPM vertical full-heat fan

Where's Fresh Roast SR500? The design is relatively simple, let the hot air blow directly from the bottom of the cylindrical glass baking room, the beans will fly freely according to the air volume, because the hot air will also form irregular bubbles due to the hindrance of the beans, resulting in a certain degree of uneven baking. In addition, in order to blow up the beans in a large area, the air volume must be quite large, so that the surface of the beans is dehydrated too fast. I will not have time to fully introduce the heat into the inside of the beans to fully develop the flavor, and the beans are already overcooked. In order to improve the controllability of SR500 and the more variability of bean baking, an earlier article "paying homage to Michael Sivetz with the advanced inner cup of SR500" has been published, which revamped the air intake and baking chamber of SR500.

Now, under the Buddha's heart of Jian Xin Cai Dong, the transformation mechanism of SR500 is made into a stainless steel kit, so that I have been cutting aluminum plates by hand and have no doubts about food safety.

The SR500 kit developed by Luo Xin Cai Dong has 2 pieces on the slope, one piece is wide and can be used in the bakery of the original SR500 factory, and the other piece is narrow and is used in conjunction with the use of Shen-style inner cups (photo source: Tsai Dong)

SR500 with Shen-style inner cup, baking room after using Cai Dong kit

After SR500 uses Dong Tsai's kit, with or without Shen-style inner cup, it has changed from a floating air type to a flow bed type hot fan. However, in the case of not using the inner cup, the maximum amount of baked beans is reduced to about 70 grams because the volume of the baking chamber is partially occupied by the slope. If matched with a Shen-type inner cup, the original baking capacity of 100 meters 120 grams can be maintained. Using the kit of SR500, the baking room bean wheel is like the following film (the film is shot using the slope I cut by hand with Shen-style inner cup, and the effect of using Cai Dong slope is more than 90% similar.)

In order to test the effect of SR500 with slopes of various sizes, a lot of time was spent on cutting aluminum plates, but now with Cai Dong's slope, you can focus on the baking control. Originally, there was a RoR theory that wanted to challenge Scott Rao with fluidized bed SR500, so it took some effort to find the best point for bean temperature measurement, which turned out to be a waste of effort, because even if it was reformed into a fluidized bed, the temperature measurement point buried in the bean pile on the side of the slope would not be directly blown by the intake hot air, and the measured temperature and trend were still very close to the exhaust temperature measured near the top of the cup. So give up the bean temperature and the pursuit of the RoR curve and focus on the comparison of baking rhythm and flavor.

Blue line: bean temperature, red line: row air temperature, use Cai Dong kit without Shen type inner cup, not preheated, bake from room temperature

The picture above shows that SR500 uses Cai Dong kit directly without Shen type inner cup to bake 70g Xidamobamobangbei in the sun. The temperature measurement point of the blue line is near the middle screw of the slope (bean temperature), and the temperature measurement point of the red line is near the cup edge of the baking room (discharge temperature). There is really little difference. Because the beans are not preheated, the beans are directly heated at room temperature, so there is no reheating point, and the initial RoR is more than 100 degrees. The baking control of this cup is that the air volume is dynamically maintained at the minimum air volume that can make the beans move smoothly, low is used in the period of dehydration and drying, middle is used before turning brown after yellowing, and then adjusted back to low after an explosion. The idea of baking is that the structure of sun-dried beans is relatively unfavorable, and the heat is transferred to the bean core. If a large amount of air is used, the baking gradient of the bean table and the bean core will be enlarged, resulting in an undercooked inside. Therefore, the firepower will warm the beans with low firepower (200 degrees into the air temperature), promote homogenization for a long time, and then increase the firepower (medium fire into the air temperature of 225C) in the middle of Mena's reaction to make incense. In order to avoid over-burnt fragrance on the surface after an explosion, the fire will be reduced and returned to low. After blowing cold, add the beans, the total baking time is about 6 minutes.

When the beans are baked at room temperature, the picture is to give the beans plenty of time to warm up. The disadvantage is that it is difficult to compare them when baking the next cup, which will not adversely affect the flavor of the batch.

For the same Sidamo Bangbei sun, use Shen-style inner cup with Cai Dong kit to bake 100g, the graph is as follows (only measure the air temperature of the top row of the cup)

The same does not preheat from room temperature to bake, this time slightly change the rhythm, in the dehydration and drying stage when the beans turn white, the firepower is pulled up from low to high, then dropped to Medium before the explosion, and then switched back to low before the beans, the baking concept is the same as the previous batch, just try a different rhythm and firepower.

Compared with the two batches of straight-through test, the two batches can appropriately show the characteristics of the beans, and none of them have a sense of bitterness. with higher firepower, the aroma of the second batch of Meina period is higher.

The following lesson, in order to achieve the baking of beans about a minute after the start of the explosion, there must be a balance of sweet and sour fragrance and no underdeveloped taste. It can be a challenge for baking beans with SR500.

Also, if the beans are washed with water, how can SR500 bake them? As shown in the following picture, how about firepower from large to medium to small? As long as it can be baked thoroughly, there is no need to set a standard for ever-changing baking methods. This baking method has a good effect on washing hard beans. The curve baking is 100g of Kenya AB bourbon, and the red curve is the air temperature.