Drying of tubers and water losses
Evaporation
During storage of potatoes water evaporates through the skin, wounds and sprouts. Much more water can disappear through wounds and sprouts than through mature skin. The ratio of the amount of water loss per unit of area of the skin, sprouts and wounds is 1:100:300 respectively. Therefore evaporation is relatively high if potatoes are damaged or have a weak skin and are not cured.
CURING TUBERS
Tuber sprouting also leads to high evaporation losses.
Ventilation of potatoes
In the evaporation process water from the tuber is taken up by air surrounding the tuber. In a stack of potatoes circulation of air or ventilation is essential to keep the surface of the potatoes dry, to remove heat and CO2, and to supply oxygen. As a result there will always be weight losses (e.g. 1.5 % of fresh weight during the first month of storage and 0.5% for each additional month is possible).For effective drying of potatoes it is necessary to assess suitability of the air for this purpose first.
Suitability of air for drying
Condensation
When cooled potatoes come in contact with air of a higher temperature there is the risk of condensation of water on the skin surface. To avoid this problem potatoes from a refrigerated store should be gradually heated up before unloading the store.