Whether you are transporting biological samples across the country or storing them long term in your laboratory, choosing the right cryogenic vessel matters enormously. A dry shipper dewar and a liquid nitrogen storage dewar serve very different purposes, yet the two are frequently confused at the point of purchase. This guide explains both clearly and helps UK laboratories make the right decision.

What Is a Dry Shipper Dewar?

A dry shipper dewar is a cryogenic vessel specifically designed for the safe transport of biological samples at liquid nitrogen temperatures. Unlike a conventional dewar, a dry shipper holds liquid nitrogen within an absorbent material inside the vessel wall rather than as a free liquid. This means there is no free liquid nitrogen present when the unit is in use.

Because the nitrogen is absorbed rather than free flowing, dry shippers are classified as non-spillable and are approved for air transport under IATA regulations. This makes them the vessel of choice for IVF clinics, andrology laboratories, and research facilities sending samples between sites.

Cryolab supplies the CryoStork range of dry shippers, available in capacities from 2 litres to 10 litres, with hold times of up to 10 days depending on the model selected.

What Is an LN2 Storage Dewar?

An LN2 storage dewar, also referred to as a liquid nitrogen storage dewar or simply a storage dewar, is designed for the long term preservation of biological material within a laboratory environment. These vessels hold free liquid nitrogen and maintain temperatures of minus 196 degrees Celsius, providing the stable cryogenic environment required for the storage of embryos, oocytes, sperm, and other biological samples.

Storage dewars are available across a wide range of capacities. Smaller laboratory dewars of 20 to 50 litres are commonly used in IVF clinics and andrology units. Larger vessels of 95 litres and above are used where sample volumes are higher or where longer intervals between liquid nitrogen refills are required.

Cryolab supplies the CryoCan and CryoNest ranges of LN2 storage dewars, covering capacities from 30 litres to 500 litres. All vessels are designed for use in HFEA-licensed facilities and comply with relevant UK laboratory safety standards.

Dry Shipper Dewar vs Storage Dewar: Key Differences

The most important distinction is purpose. A dry shipper dewar is built for transport. A storage dewar is built for stationary, long term use in a laboratory setting. Using a storage dewar for transport is not recommended as free liquid nitrogen presents a spillage risk during movement. Using a dry shipper for long term storage is equally unsuitable as the hold time is limited and the vessel is not designed for continuous use over weeks or months.

A second difference is the liquid nitrogen itself. In a dry shipper, the nitrogen is absorbed and there is no free liquid present. In an ln2 storage dewar, free liquid nitrogen is present at all times and needs to be monitored and replenished at regular intervals.

For laboratories managing both transport and storage requirements, Cryolab recommends maintaining both vessel types. The CryoStork range handles all sample transport needs while the CryoCan and CryoNest ranges provide long term storage capacity.

Liquid Nitrogen Dewar Cell Storage: What Laboratories Need to Know

When using a liquid nitrogen dewar for cell storage, the internal organisation of the vessel is as important as the vessel itself. Samples stored in an LN2 dewar need to be organised using a structured system of cryocanes, cryosleeves, and goblets to ensure samples can be located quickly and safely without prolonged exposure to ambient temperatures during retrieval.

The CryoNest range from Cryolab is specifically designed with internal organisation in mind. CryoNest vessels feature a canister system that allows laboratories to store and retrieve individual canisters without disturbing the rest of the vessel contents, reducing temperature fluctuation and improving sample security.

For HFEA-licensed clinics, traceability of stored material is a regulatory requirement. Every sample stored in an LN2 dewar should be clearly labelled and recorded in line with the HFEA Code of Practice. Cryolab supplies CBS High Security Straws and compatible labelling solutions to support full traceability across your storage dewar inventory.

Dewars LN2: Choosing the Right Capacity for Your Laboratory

Selecting the correct capacity for your laboratory is one of the most common procurement challenges when sourcing dewars for LN2 use. Choosing a vessel that is too small means more frequent refilling, greater liquid nitrogen consumption, and a higher risk of samples being compromised if a refill is missed. Choosing a vessel that is too large for your sample volume wastes laboratory space and increases nitrogen evaporation.

As a general guide, smaller IVF clinics and andrology units typically work well with a 30 to 50 litre storage dewar. Larger clinics or those storing samples across multiple patient cohorts will generally require vessels of 95 litres and above. Research facilities with high sample volumes often operate multiple large capacity storage dewars in parallel.

Cryolab’s team is available to advise on capacity selection based on your specific sample volumes and workflow. Contact us directly for a recommendation tailored to your laboratory.

UK Supply and Technical Support

Cryolab Ltd is a UK-based supplier of cryogenic storage and transport solutions for IVF clinics, andrology laboratories, research facilities, and veterinary practices. All dry shipper dewars and LN2 storage dewars are held in UK stock and are available for next-day delivery to mainland UK addresses.

Technical support is available directly from the Cryolab team, with no need to go through international distributors. Cryolab is ISO 9001:2015 certified and has been supplying cryogenic equipment to UK laboratories for over two decades.

Contact Cryolab

To discuss your dry shipper dewar or LN2 storage dewar requirements, contact the Cryolab team directly.