Method for freezing viable cells

A method and a device for improved freezing of biological containing living cells is disclosed. Directional cooling coupled with agitation, preferably rotation, of the vessel containing the biological sample allows for the freezing of large volume samples at much greater rates than before. Whether a sample is large or not, the greater thermal homogeneity during the freezing process as well as the resulting crystal morphology yield a frozen sample which is exceptionally suited for lyophilization.