While the grain drying process itself is quite simple, there is scope for significant problems to develop and for the barley quality to decline if the drying is not done properly. Avoid over drying, as very dry grain has a lower weight and grain with a low moisture level takes longer and is more expensive to extract. Grain dryers are generally classified as two types, batch and continuous-flow. Both types have features that would make them suitable for different situations. A batch machine dries a fixed amount of grain over a period of time.
Dry grain is emptied from the bin and a fresh batch of moist grain is added for drying.
Batch machines are well suited to drying small quantities of grain. A continuous-flow machine dries moist grain whilst it flows from the inlet to the outlet. In a continuous-flow system, air temperatures are generally higher, as heating is applied more uniformly, for a shorter period of time and to a thinner layer of grain. Continuous-flow machines are generally more efficient if drying large quantities of the same type of grain and have a lower requirement for labour. Both batch and continuous-flow driers come in stationary or portable varieties.