Coffee drying processes and their impact on the industry

Abstract

Drying is one of the most crucial stages to ensure the quality and safety of coffee. It has been evidenced that different types of surfaces and techniques used in solar drying can affect the final quality of coffee. Traditional solar drying, is particularly influenced by the climactic conditions of the site where it is carried out, including humidity and temperature; there are other methods used in the industry to counteract these advantages. This article explores existing literature on the performance of different ways of applying solar drying (on different surfaces and with covers), different types of mechanical drying (rotary dryers, static layer dryers, dryer silos and fluidized bed drying); as well as the theoretical possibility of using freeze-drying on coffee beans for drying instead of instant soluble coffee, which has been historically used. Mechanical drying methods tend to have shorter drying times; however, the quality of coffee starts to decrease if the temperature exceeds 40°C. While freeze-drying tends to better preserve flavours and aromas, it also incurs higher production costs, limiting its application as an alternative drying method in commercial coffee despite its advantages in terms of final product quality.