The subject of the present study was to determine the structural changes that might occur to yeast cake by A and B producers depending on the storing conditions. The yeast cake was stored for six months in different thermal conditions: constant -12ºC and constant -22ºC and also at variable (-12ºC;-22ºC). The degree of staling changes under different conditions were examined on the basis of static compression tests with the use of INSRON 5543. The study presents mathematic models of stress changes in the cake bite under examination subjected to squeezing along with statistics (R² determination coefficient, φ² indetermination coefficient and R correlation index), allowing for the choice of such equation which would best describe the changes of the occurring condition observed at the time of storage. The obtained data proved that the most beneficial thermal storage variant was the temperature of – 22ºC. The cake stored under such condition revealed the least degree of staleness which allows for a statement that the starch forms order processes were not that much advanced. It was found that in both cases the square function best reflected the character of the product staleness degree.