Laboratory cooling racks and containers: how can samples be kept cold during handling?

Cooling racks and refrigerated containers maintain the thermal stability of your samples during preparation, analysis or local transport. DNA, enzymes, antibodies, metabolic extracts or clinical samples: holding 0–4 °C, -10 °C or -20 °C limits degradation and improves data reliability. Depending on the task, choose a portable refrigerated container, a high-conductivity aluminium rack or a plastic rack with gel insert (PCM). Reusable, numbered and compatible with PCR, 0.5/1.5/2 mL microtubes and cryovials, they deliver controlled cooling… without the soggy puddle from melting ice.

What are the different types of tube racks and cooling containers?

Three families cover most applications.

• Cooling container: insulated case with PCM or eutectic plates to precondition (fridge, freezer). It protects against warming for several hours and travels easily between bench, analysis room or cold room. Some models accept dry ice for lower temperatures.

• Aluminium cooling block: anodised block with high thermal conductivity. It quickly equalises tube temperature, offers excellent homogeneity and a durable surface, often autoclavable. Ideal for PCR set-up, enzymatic assays or quality control that requires tight stability.

• Plastic cooling rack (with gel insert): lightweight, virtually no condensation, often colour coded and numbered. The gel insert targets a specific band (0 °C, -10 °C, -20 °C) to maintain sensitive reagents. Simple upkeep, safe in routine use.

Selection criteria: target temperature (0/4, -10, -20 °C), hold time, supported formats (PCR 0.2 mL, microtubes 1.5/2 mL, cryovials 1–2 mL), compatibility with dry ice, chemical resistance, cleaning (alcohol, soapy water, autoclave for aluminium), presence of lid, numbering, temperature indicator and footprint.

At-a-glance comparison:

Type	Thermal principle	Typical applications
Cooling container	Insulation + precharged PCM/eutectic	Short transport, bench work without ice, holds 0 to -20 °C
Chilled aluminium block	Fast conduction, high inertia	PCR, enzymes, QC: fine homogeneity and stability
Plastic cooling rack	Dedicated gel insert (PCM)	Everyday use, low condensation, various formats

In which applications are refrigerated racks and containers used?

• Life sciences: preparation of PCR master mixes, keeping enzymes, RNA/DNA and antibodies at 0–4 °C during assay set-up.
• Pharma/biotech: short-term storage of critical reagents for formulation development, bioanalysis and stability samples.
• Agri-food: keeping extracts cold, on-bench microbiological QC and enzymatic assays.
• Environment: sample prep/aliquoting of water, soil and leachates without breaking the cold chain.
• Cosmetics & chemicals: temperature-sensitive formulation work, raw material QC, low-temperature viscometry.
• Clinical & QC: intra-lab transport of specimens, immunoassay reagents and calibrators under a secure lid.
Shared benefits: repeatability, fewer freezer door openings, no meltwater, and improved safety and ergonomics at the bench.

The different types of cooling racks and containers available

Frequently asked questions about cooling racks and containers

How do I choose the right temperature (0, -10, -20 °C)?
Base your choice on biomolecule sensitivity and working time. 0–4 °C is sufficient for enzymes/antibodies; -10/-20 °C for PCR reagents and highly thermosensitive matrices.

How long will it hold on the bench?
Depending on the model and ambient conditions, expect 2–6 h at 0–4 °C and 1–3 h at -20 °C. Check the datasheet and precondition the PCM correctly.

Can I use dry ice?
Only if the product is specified as compatible. Wear PPE, avoid airtight lids and follow ventilation guidance.

Are the aluminium racks autoclavable?
Most are. Plastic racks with gel inserts generally aren’t. Refer to the manufacturer’s symbols.

How do I clean without damaging the insert?
70% alcohol, soapy water. No prolonged immersion or strong solvents. Dry thoroughly before re-cooling to limit condensation.

Compatible with 96-well PCR plates?
Choose a dedicated plate/strip model or adapters. Aluminium blocks provide the best uniformity across the plate.

How do I minimise condensation on tubes?
Use a lid, pre-dry the block, work in a low-humidity area and wipe regularly. 0 °C PCMs reduce the effect compared with ice.