A cryogenic storage dewar is a precision vacuum-jacketed vessel used to store liquid nitrogen and the biological samples held within it at -195.8 degrees C. For UK IVF clinics, sperm banks, and research institutions, selecting the right dewar is not a purchase decision to make on price alone – the vessel that holds your patients’ embryos and sperm needs to be matched precisely to your sample volume, access frequency, and storage duration requirements.

What does static evaporation rate tell you about a cryogenic storage dewar?

Static evaporation rate – quoted in litres per day – tells you how much liquid nitrogen the vessel loses when sitting undisturbed at 20 degrees C ambient temperature. A well-engineered 35-litre dewar might have a static evaporation rate as low as 0.08 litres per day. A cheaper vessel of similar capacity might lose 0.3 litres per day. Over a year, that difference is roughly 80 litres of LN2 – a meaningful operational cost at UK supply prices.

How does neck diameter affect a cryogenic storage dewar’s performance?

The neck is the main point of heat ingress on any vacuum-jacketed vessel. A narrow neck minimises this effect, keeping evaporation rates low and reducing moisture ingress that can cause ice build-up. Most long-term storage dewars use necks of 50mm or less. Wide-neck dewars – 100mm or above – are designed for applications where frequent, rapid access matters more than evaporation efficiency.

What is the correct way to store samples inside a cryogenic dewar?

Samples should be organised on numbered canisters with a corresponding paper or digital inventory log. Each canister position should be assigned to a specific patient or batch, and the log should be updated every time a sample is added or removed. HFEA-licensed facilities are inspected on their traceability systems – an unorganised dewar is one of the fastest ways to generate an inspection finding.

A cryogenic storage dewar with poor internal organisation is not a storage system – it is a liability. The vessel is only as reliable as the inventory management behind it.

View Cryolab’s CryoNest storage dewar range or speak to the team about your lab’s configuration.