The color of dried chili peppers produced in a chili dryer is poor. Here's why!

The fundamental external variables in the chili dryer drying process are temperature, air velocity and direction, the physical form of the chili peppers, agitation conditions, and the dryer's material holding method during the drying operation. External drying conditions are particularly important during the initial drying phase, when removing unbound surface moisture. This is because moisture on the chili peppers' surface diffuses as vapor through the air film on the chili peppers' surface. This mass transfer process is accompanied by heat transfer, so enhancing heat transfer can accelerate drying.

In some cases, the drying rate should be controlled. After the free moisture is removed, a large moisture gradient is generated from the interior to the surface. Excessively rapid surface evaporation will lead to significant shrinkage, a phenomenon known as overdrying and shrinkage. Excessively rapid drying can cause crusting on the chili peppers' surface, increasing the critical moisture content and hindering the overall drying rate. This can cause high internal stress, resulting in wrinkling, cracking, or bending, and darkening of the peppers' color.

Properly controlling the temperature and humidity at different times during the chili dryer's drying process can ensure a more vibrant color and a more beautiful shape.