Methods of supercooling aqueous samples

A method of supercooling an aqueous sample comprising a biological sample, the method comprising:

• providing a container comprising an aqueous sample comprising a biological sample;
• applying a layer of an immiscible liquid phase of sufficient thickness to separate the aqueous sample from air to diminish primary heterogeneous nucleation at the aqueous sample/air interface, wherein the volume of the aqueous sample is greater than 10 ml, and wherein the immiscible liquid phase forms a surface sealing layer that remains intact for more than 7 days to remove an interface between the aqueous sample and the air and is not mixed into the aqueous sample;
• and
• supercooling the aqueous sample to a temperature that is below 0° C., wherein the aqueous sample is supercooled to a degree of supercooling (ΔT) that is greater than 10° C., and wherein the aqueous sample is maintained in supercooled state for more than 7 days.