Do you know how long it takes for your product to freeze?
Factors that determine food freezing time
1. Temperature and air velocity
The most decisive parameter in IQF freezing (Individual Quick Freezing) is heat transfer. In IQF tunnels, operating temperatures range between –35 °C and –45 °C, with high-velocity airflows that surround the product to achieve fast and uniform freezing.
Palinox industrial freezing tunnels are designed with air distribution systems based on CFD (Computational Fluid Dynamics) simulations, ensuring thermal uniformity and eliminating hot spots or areas with insufficient airflow. The result: shorter freezing times and more consistent results.
Depending on the product, Palinox has developed various tunnel models with customized air channeling systems to meet specific requirements — optimized engineering in fans and evaporators ensures the right pressure and airflow for every application.
2. Product type and size
The size, shape, and exposed surface of the product determine its freezing rate. Thinner products release heat more quickly.
Typical examples in industrial freezing:
- IQF shrimp (20–30 g/unit): 6 to 8 minutes
- Peas or diced vegetables: 3 to 5 minutes
- Fish fillets (150–200 g): 25 to 35 minutes
- Meat pieces or whole poultry: up to 90 minutes, depending on thickness
That’s why Palinox freezing tunnels allow adjustment of parameters such as air velocity, residence time, and conveyor/belt type according to each product and format.
3. Water and fat content
Water content directly affects food freezing. Water requires a large amount of energy to change from liquid to solid, especially during the crystallization phase (between –1 °C and –2 °C).
Products with high water content — such as fruits, vegetables, or seafood — therefore take longer to freeze than those rich in fat.
H2O
Graph of temperature change over time. At temperatures where water changes state, there is a reduction in the rate of temperature change.
Fats, on the other hand, cool quickly but may solidify more slowly, so it’s important to control the final stages of freezing to avoid soft cores or “core warm” zones.
4. Initial product temperature
Proper pre-chilling can reduce freezing time by up to 30%.
A product entering the tunnel at 2–4 °C freezes much faster than one at room temperature.
In Palinox-designed lines, IQF freezing is integrated with pre-cooling systems, ensuring a more efficient and stable thermal transition.
5. Freezing technology
Each technology used in industrial freezing has a distinct thermal profile and processing time:
CYCLONE: Linear forced-air IQF tunnel
Features a dual airflow system that directs air above and below the product. It has two independent conveyor belts allowing speed and configuration adjustments according to product type and thermal behavior.
SPIROBLOW: Spiral forced-air IQF tunnel
Its spiral configuration allows customization of belt width and number of tiers. With an excellent footprint-to-belt-length ratio, it achieves high performance in reduced spaces — ideal for large or thermally resistant products.
BLIZZARD: Fluidized bed IQF tunnel
Uses an upward airflow from the base to keep the product in constant suspension, preventing clumping and ensuring homogeneous treatment piece by piece. A highly efficient and versatile solution for light or small-sized products.
Palinox designs each industrial freezing line to measure, selecting the most efficient technology according to the product type and production capacity.
How to estimate your product’s freezing time
Theoretically, freezing time can be estimated using Plank’s equation, which considers:
Thermal conduction factors:
- Thermal conductivity of the food
- Initial temperature
- Final temperature
- Product geometry
External convection factors:
- Exposure area or heat transfer surface
- Surface temperature
- Freezer tunnel temperature
- Airflow rate and pressure
That’s why Palinox conducts pilot tests for each product type to determine the optimal IQF freezing time, including thermal monitoring, energy analysis, and texture validation.
Optimized Palinox engineering: every second counts
Palinox industrial freezing tunnels are engineered to maximize performance through:
- Precise control of air temperature, flow rate, and pressure
- Variable speed control on conveyor belts
- Homogeneous product distribution across the freezing surface
- State-of-the-art evaporator and refrigeration systems
- Modular, flexible design and simplified maintenance
- Advanced control software with thermal recording and traceability
Every detail is aimed at optimizing food freezing, ensuring productivity, uniformity, and energy efficiency.
Conclusion
Knowing the exact freezing time of your products not only improves quality but also reduces energy consumption and maximizes process profitability.
Industrial freezing is a science of precision — and at Palinox, we turn that science into optimized engineering for every customer.
Do you want to know how long it takes for your product to freeze?
At Palinox, we analyze your product and help you define the most efficient IQF freezing time for your production line.
Contact us for a personalized test and discover how to optimize your industrial freezing process.
