The 50 litre dewar has been in IVF labs for decades. Here is why it is still there.

Some pieces of lab equipment come and go. The 50 litre liquid nitrogen dewar is not one of them. It has been a fixture in IVF labs, andrology units, and veterinary reproduction facilities for long enough that most practitioners do not question its presence, they just order another one when the old one starts underperforming.

That longevity is not accidental. The 50 litre configuration solves a genuine problem in a way that neither smaller nor much larger vessels do quite as well.

The problem it solves

Clinical cryogenic storage needs to be accessible, safe, and manageable without specialist infrastructure. A 20 litre dewar gets accessed constantly and refilled frequently. A 200 litre vessel requires more planning, more space, and more liquid nitrogen budget than a mid-sized clinic can justify. The 50 litre vessel sits in a range where the refill interval is measured in weeks rather than days, the vessel can be moved by two members of staff, and the sample capacity covers a meaningful portion of an active patient list.

What good looks like at this size

A well-specified 50 litre dewar will hold charge for at least 50 days under normal clinical conditions. The neck opening should be wide enough to accommodate standard canisters without forcing. The lid should close with a positive seal rather than resting loosely. The external surface should remain at room temperature rather than sweating, which indicates insulation integrity.

Cryolab's CryoCan range covers both six and ten canister configurations at the 50 litre size. For larger capacity, the CryoNest XL is worth looking at. Both are available through cryolab.co.uk.