The choice between individually quick frozen and block frozen fruit is presented in most supplier literature as a quality question, with IQF as the premium answer. That framing is wrong often enough to be expensive. It is a process question, and for a large share of industrial buyers the correct answer is block.
What each format physically is
IQF means the individual pieces are frozen separately, typically on a fluidised bed where a strong upward air flow keeps the fruit in suspension while the surface freezes, then on a belt or spiral to complete the freeze. The output is free flowing. Every piece can be poured, weighed and dosed independently.
Block frozen fruit is frozen as a mass, either in a carton or a bin in a blast room or tunnel, or as a plate-frozen slab. The output is a solid unit that has to be broken, sawn or thawed before use. Loose frozen sits between the two: frozen on a belt without full fluidisation, mostly free flowing but with clumps.
Where the cost difference actually comes from
The premium on IQF is not arbitrary. It comes from four places, and knowing which ones apply to your fruit tells you how large the premium should be.
| Cost driver | Why IQF costs more | Relative weight |
|---|---|---|
| Freezing energy | Higher air velocity and lower air temperature for a shorter dwell | Significant, but the smaller share |
| Throughput per hour | A fluidised bed handles less mass per square metre than a blast room | The largest single driver |
| Yield loss | Fines, breakage and dehydration losses on a belt line | Fruit dependent; high on soft berries |
| Packaging | Lined cartons and retail formats rather than bulk bins | Moderate, and it scales with unit size |
Note what is not on the list: raw material. The same fruit goes into both. A supplier quoting a large IQF premium on a fruit that freezes easily and packs in bulk cartons either way is quoting a market position rather than a cost.
What each format does to the fruit
The quality argument for IQF rests on freezing rate. Faster freezing produces smaller ice crystals, less mechanical rupture of cell walls, and therefore less structural damage and lower drip loss on thawing. That is real physics and it is measurable.
But the size of the effect depends entirely on the fruit. A firm, low-moisture, thick-skinned fruit – cranberry, gooseberry, blackcurrant – loses very little to a slower freeze because there is less free water to migrate and the cell walls are robust. A soft, high-moisture fruit – raspberry, ripe pear, strawberry – loses a great deal. The IQF premium is worth paying in inverse proportion to how robust the fruit is.
A useful test: thaw a controlled sample of both formats and weigh the drip. If the difference is within your process tolerance, you are paying for a property you are not using.
There is a second quality effect that runs the other way. A block has a very low surface-area-to-mass ratio, which makes it markedly more resistant to freezer burn and to temperature abuse in a long or poorly-controlled cold chain. IQF fruit in a partly-used carton, cycled through a few warm episodes, will glaze, clump and dehydrate at the surface long before a block would. For a distant destination with an uncertain last mile, block is the more forgiving format.
Which applications genuinely need IQF
IQF is required, not merely preferred, where the individual piece has to remain visible and separate.
- Retail frozen fruit packs, where the consumer expects to pour a portion.
- Bakery inclusion, where the fruit is dosed by count or scattered onto a base.
- Ice cream and dairy inclusions added after pasteurisation.
- Any automated dosing system that meters by volume from a hopper.
- Food service packs where a kitchen takes out part of a bag and returns the rest.
Block is the correct answer where the fruit is going to lose its identity anyway.
- Juice and concentrate lines, where the fruit is thawed, mashed and pressed.
- Puree and coulis manufacture.
- Jam, preserve and fruit preparation cooking, where everything goes into a vessel.
- Fruit fillings that are milled or blended before use.
- Any process where the first operation after thawing is a size reduction step.
This is the case with elderberry and much of the blackcurrant trade: fruit destined for a press has no use for free flow, and paying for it is a pure cost transfer.
The handling arithmetic nobody quotes
Format choice changes costs beyond the fruit price, and the direction is not always obvious.
Block reduces packaging cost per kilogram and increases pallet density, which lowers freight per tonne. But it requires tipping or breaking equipment at the receiving plant, it commits you to processing a whole unit once opened, and it makes partial use impossible. A 300 kg bin is only economical if you use 300 kg.
IQF increases packaging and freight cost per kilogram, but it allows partial withdrawal, small batch runs, and accurate dosing without waste. For a manufacturer running many short batches against different recipes, that flexibility can outweigh the entire format premium.
Specifying the format properly
Whichever format you choose, three lines belong in the specification.
- The format itself, named explicitly: IQF fluidised bed, loose frozen, block frozen in carton, or plate frozen slab. The words are not interchangeable and some suppliers use loose frozen and IQF as if they were.
- A free-flow or clump tolerance where IQF is specified, expressed as a maximum percentage of agglomerated pieces on a defined test. Without this line, an IQF claim is unverifiable.
- A drip loss maximum on a stated thaw protocol, which is the outcome measure that tells you whether the freeze was actually fast, regardless of what the format is called.
The third line is the important one. Format describes the equipment; drip loss describes the result. A well-run block operation can beat a badly-run IQF line on drip loss, and the only way you will know is by measuring it.
Storage and transport conditions are the same for both formats: minus 18 degrees Celsius or colder, with the handling guidance in the Codex code of practice CXC 8-1976 and the equipment requirements in the ATP agreement. The cold chain guide covers the corridor side, and the packaging guide covers the pack specification in more detail.