Considerations on Drying

In past discussions of drying foods, I’ve considered some different types of dryers and modeling approaches. This article contains some of the other factors that might affect the choice of a dryer and its operation.

First, here is a brief review of the fundamentals. Drying involves four transport processes:
• External heat transfer from source to surface of food.

• Internal heat transfer from surface to moisture.

• Internal mass transfer of moisture to surface of food.

• External mass transfer of mo…