Ice Requirement & Keep the Load Cold in Transit
Ices fish
Ice keeps fish, milk and produce cold in transit by absorbing field heat as it melts — enter the produce mass and the heat to remove to get the ice needed and the ice-to-produce ratio.
Ice for the cold chain
Next: pack about 17.1 kg of ice (≈17.1% of the produce weight) to pull 100 kg down by 15°C — add more for long transit and warm weather.
This covers only the field-heat to remove (mass × specific heat × ΔT ÷ 334 kJ/kg latent heat of ice); real journeys need extra ice for heat leaking through the box and time in transit.
Ice requirement — key facts
- Ice needed
- heat to remove ÷ 334 kJ/kg
- Latent heat
- ≈ 334 kJ per kg of ice
- Cools by
- absorbing heat as it melts
- Fish ratio
- ≈ 1:1 to 1:3 ice-to-fish
- Long/warm trip
- add extra ice margin
- Holds at
- 0 °C while melting
- Ice form
- flake chills, block lasts
- Privacy
- Runs in your browser; nothing uploaded
Enough ice to last the whole journey
Ice is the cheapest coolant in the cold chain, and it works because melting a kilogram soaks up about 334 kJ of heat at 0 °C. That melting heat pulls the field warmth out of freshly landed fish, just-milked milk and sun-warmed vegetables, then holds them cold by absorbing the heat that keeps leaking through the box. Pack too little and the ice runs out mid-trip and the load warms; size it right and the produce arrives chilled and saleable.
This tool gives the heat to remove, the ice needed, the ice-to-produce ratio and the produce mass so you can pack with confidence. Use it to ice fish boxes, milk cans and produce crates, and to add a margin for long, warm runs. Pair it with the Cold Room Cooling Load, Precooling Time and Produce Transport Cost tools for a full cold-chain plan.
Pack the right ice
Match ice mass to the heat the load carries.
Survive the trip
Add a margin so ice lasts to delivery.
Use a simple ratio
Pack by an ice-to-produce rule of thumb.
Protect the catch
Keep fish, milk and produce cold and saleable.
Frequently Asked Questions
How is the ice requirement calculated?+
Ice cools by absorbing heat as it melts, taking about 334 kJ per kilogram (the latent heat of fusion). So ice needed = heat to remove ÷ 334 kJ/kg. The tool turns the heat you need to pull from the produce — to chill it and to offset the heat leaking in during transit — into the kilograms of ice that will absorb it.
Why does ice keep produce cold?+
Melting ice holds at 0 °C and soaks up a large amount of heat for its weight as it changes from solid to liquid. That melting heat is what keeps fish, milk and vegetables cold: the field heat in the produce and the heat leaking through the box go into melting the ice instead of warming the load. When the ice is gone, the cooling stops.
What is the ice-to-produce ratio?+
It is the weight of ice relative to the produce, often quoted as a percentage. The calculator reports it so you can pack by a simple rule of thumb — for fish, ratios around 1:1 to 1:3 ice-to-fish are common depending on distance and weather. A higher ratio buys more cooling margin for long or hot journeys.
How much extra ice for a long or warm journey?+
Heat leaks in continuously through the box walls, so a longer trip and a hotter ambient both mean more total heat to remove — and more ice. Add a margin on top of the chilling ice for transit, and increase it further in hot weather or with poor insulation. Running short midway lets the load warm and spoil.
Does the type of produce matter?+
Yes — different produce starts at different field temperatures and has a different specific heat, so the heat to remove varies. Fish landed warm, milk straight from milking, and sun-warmed vegetables each carry their own field heat. Enter the heat to remove for your load; the latent heat of ice (334 kJ/kg) stays the same.
Why 334 kJ per kilogram?+
That is the latent heat of fusion of water — the energy it takes to melt one kilogram of ice at 0 °C without changing its temperature. It is large compared with simply warming water, which is why ice is such an effective, cheap coolant for the cold chain. The calculator divides the heat load by this figure to get the ice mass.
Does the ice keep the produce or just cool it?+
Both — first the melting ice pulls the field heat out and chills the produce toward 0 °C, then the remaining ice holds it there by absorbing the heat that leaks in during transit. Size the ice for both jobs: the initial chill plus the holding through to delivery, or the load warms before it arrives.
Can I use flake, block or gel ice?+
The heat each absorbs per kilogram is essentially the same (≈334 kJ/kg), so the mass from this tool applies to any. Flake and crushed ice contact produce better and chill faster; block ice melts slower and lasts longer for transit; gel packs are reusable. Choose the form for the job and pack the calculated mass.
Are the figures precise?+
They're solid planning figures. Real ice use also depends on box insulation, packing, ambient temperature, melt drainage and how often the load is opened. Add a safety margin, especially for long warm trips, and check the load on arrival — the ice mass steers the packing, conditions decide the rest.