Because drying removes moisture, the food becomes smaller and lighter in weight. When the food is ready for use, the water is added back and the food returns to its original shape. If higher temperatures are used, the food will cook instead of drying. The food will eventually mold. Thus, the drying process should never be hurried by raising the drying temperature.
Low humidity aids the drying process.
Food contains a lot of water. To dry food, the water must move from the food to the surrounding air. If the surrounding air is humid, then drying will be slowed down. Increasing the air current speeds up drying by moving the surrounding moist air away from the food. To speed the drying time, increase the air flow.