Snap Freezing


Snap freezing is the technique in which a sample is rapidly frozen using dry ice, a dry ice/ethanol slurry or liquid nitrogen.  Samples frozen in this manner include bacteria and viral stocks, cell lysates, proteins, and tissues.  Snap freezing reduces the chance of water present in the sample forming ice crystals during the freezing process, and better maintains the integrity of the sample.  In the case of tissue or lysates, snap freezing slows the actions of proteases and nucleases to inhibit degradation of molecules such as RNA or proteins.


Snap freezing in dry ice
Snap freezing samples in dry ice directly, or in alcohol
slurries, results in random layout that can result in variability, misidentification and errors in processing.

Snap freezing in dry ice using a CoolRack

Place a CoolRack® tube module on dry ice (or liquid nitrogen) and it will rapidly adapt to the dry ice temperature (-78ºC in approximately 6-7 minutes).  Snap freeze your samples in this organized, consistent and reproducible method.



CoolRack thermo-conductive modules can also be used in liquid nitrogen.* After approximately 15 minutes, a room temperature CoolRack module will equilibrate to approximately -140ºC and remain there while surrounded by LN2. Freezing tubes in a CoolRack keeps all tubes upright and organized, and provides uniform effortless freezing at ultra-low temperature.




 Performance test: Tests were performed with a 0.5 mL Sarstedt tube (#72.785) containing 0.25 mL water.  The interior water temperature was measured using a thermocouple probe inserted through a hole introduced into the cap and held in an axial orientation by a custom cap adaptor. Vials were placed in a dry well in the CoolRack (green) or directly into dry ice (red) and the temperature recorded. Data shown are from three different vials.  Vials frozen in the CoolRack module (green) were more consistently frozen than those inserted into dry ice directly (red).



Type of Tube

CoolRack (# of samples)

Item No.

Compatible Ice Pan 

Microfuge tubes

1.5 or 2.0 mL

CoolRack M6 (6)

CoolRack M15 (15)

CoolRack M30 (30)

CoolRack M90 (90)

CoolRack M96 (96)






1L Mini Ice Pan

1L Mini ice Pan

4L Midi Ice Pan

9L Maxi Ice Pan

9L Maxi Ice Pan

Cryogenic vials

CoolRack CF15 (15)

CoolRack CFT30 (30)

CoolRack CF45 (45)




1L Mini Ice Pan

4L Midi Ice Pan

4L Midi Ice Pan

Centrifuge tubes

CoolRack 15ml (9)

CoolRack 50ml (4)



4L Midi Ice Pan

4L Midi Ice Pan


*It is important to adhere to laboratory safety protocols when handling dry ice or liquid nitrogen. CoolRack modules can cause skin burns when cooled to ultra-low dry ice or LN2 temperatures.  Use extreme caution and protective clothing and equipment when handling CoolRack modules in dry ice or LN2.


CoolRack thermo-conductive tube 

Ice pans and buckets
 made from non-toxic EVA foam

TruCool leak-proof cryogenic vials 

 vial grabbers to protect fingers from frozen vials >

Application Note:
Click here for a printable version of this application


Quick Protocol:

1)  Place 1-2 inches of pelleted or crushed dry ice in your ice pan.

2)  Place CoolRack module on top of dry ice and wait 5-7 minutes for module to equilibrate to temperature of dry ice (~-78°C).

3)  Place your samples in CoolRack module and wait approximately 3-4 minutes for sample to freeze.*

* Depending upon your sample, freezing can be complete within 3-4 minutes. We suggest waiting for ten minutes before transferring to a -80°C freezer or liquid nitrogen.



Snap Freezing in Dry Ice Using a CoolRack Module >

Snap Freezing of Tissue Samples >

Bacteria Cryopreservation using a CoolRack Module >
Virus Cryopreservation using a CoolRack Module >



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