What IQF Means: IQF Fruit vs Block Freezing and Slow Freezing

What does IQF mean?

IQF — individually quick frozen — describes both a process and a product. After cutting and washing, the fruit pieces are dewatered and fed through a tunnel or fluidised-bed freezer, where very cold, fast-moving air keeps them apart while their surfaces freeze. Each piece freezes on its own, in minutes rather than hours, and leaves the freezer as a separate frozen piece. The pieces are then packed and held at -18 °C or colder.

“Quick” has a technical meaning. EU law defines quick-freezing as a process in which the zone of maximum ice-crystal formation is crossed as rapidly as possible, after which the product is kept at -18 °C or colder at all points once its temperature has stabilised. Speed through that zone is what protects texture.

IQF, block freezing and slow freezing compared

IQF freezes pieces separately and fast, block freezing freezes the product as one mass, and slow freezing freezes packed product in a freezer room. The results differ in handling and texture.

Purées can be frozen either way: in blocks inside bags or pails, or as frozen pellets or cubes that behave more like IQF. Ask which format a purée is supplied in, because it changes how you thaw and dose it.

Why does fast freezing protect texture?

Fruit is mostly water held inside cells. Fast freezing generally produces smaller ice crystals and reduces cellular damage. Slow freezing produces fewer, larger crystals that can distort and damage the tissue. On thawing, damaged tissue releases juice and loses its shape. Quick freezing limits this damage; it does not eliminate it.

The practical differences:

• drip loss: slowly frozen fruit loses more juice on thawing, which costs yield and dilutes recipes;
• texture: fast-frozen pieces keep more of their bite; slowly frozen pieces thaw softer;
• shape: separate pieces keep their cut geometry, which matters for toppings and inclusions.

Two limits apply. IQF cannot improve the raw material — soft, over-ripe fruit gives soft pieces however fast it is frozen. And the advantage erodes if the product warms and refreezes later: ice crystals grow during temperature swings. Our IQF cold chain guide explains how to keep it.

What does IQF change for a food manufacturer?

For a food manufacturer, IQF mainly changes portioning, yield and process fit, at a higher price per kilogram.

• Portioning. You weigh what the batch needs and reseal the pack; there is no thawing of a whole block for a partial use.
• Waste and yield. Less drip loss and fewer broken pieces mean more usable fruit per kilogram bought.
• Process fit. IQF pieces can go frozen into blenders, fruit preparations and some bakery applications, without a thawing step.
• Cost. IQF usually costs more per kilogram than block-frozen product; the comparison that matters is cost per kilogram of usable fruit in your process.

What should an IQF specification cover?

“IQF” describes the freezing method. It does not describe the fruit. A usable specification adds:

• variety or a sensory reference, and maturity;
• Brix range and the measuring method (see the typical ranges we publish in the table below — they differ widely between fruits);
• cut format and dimensions with tolerances, plus the allowed share of fines and broken pieces;
• a free-flow criterion, for example the maximum share of fused clusters by weight;
• defect limits: dark spots, peel, seeds, fibre, foreign matter;
• additive status: plain fruit, or any anti-browning agent or syrup declared;
• microbiological criteria suited to the use — stricter if the fruit will be eaten without further heating, as in smoothies or toppings;
• storage and transport temperature.

For mango in particular, our IQF mango specification guide works through each of these parameters, and IQF fruit packaging and shipping covers pack formats and container options.