During storage of potatoes, a change of the chemical composition occurs, which consists in inter alia decomposition of starch and increase of dry mass content as a result of evaporation of the part of water which may cause a culinary change. Potatoes designated for processing into fried products cannot contain more than 0.15-0.25% of reducing sugars. During the process of frying, reducing sugars react with elemental amino acid as a result of which, they form compounds of dark colour and a hazardous for health acrylamide is formed. The obtained products are bitter and their colour is undesirable. Quality of crisps, that is, defects in relation to the following was assessed: time limits of crops, temperature of tubers and sugar content in tubers after crops and during storage. The obtained results confirm the increase of dry mass and reducing sugar content and the change of colour of crisps.