CRYO - Freezing Cryo Centrifuge Tubes

For vials made of polypropylene (some models may contain silicone washers) 

They can withstand temperatures from +121°C down to -196°C. When freezing, volumes should be 10% less than listed capacity.

When filling, the cryo centrifuge tube should be filled with no more than 90% of the tube's volume (to permit expansion). Upon freezing, ensure that the entire vial is frozen at the same temperature - avoid racks that create partial insulation. The cryo centrifuge tube should be moved periodically during freezing to avoid supercooling and subsequent quick ice formation.

When freezing in liquid nitrogen, ensure that the screw cap is not overtightened. The thread and screw cap of the vial should be completely dry before closing; liquid drops will impair the seal in liquid nitrogen. 

Vials should be stored in the gas phase above liquid nitrogen. If they are immersed, the vials might develop leaks or even shatter when returned to temperature.

When removing vials from liquid nitrogen containers, always use safety equipment such as gloves, hoods, face shields etc. To thaw, place the vial into a water bath (37-40°C) and keep it in constant motion. As soon as the ice has melted, remove the vial from the water bath.