There is no official standard for dehydrated onion particle sizes. Each processor sets its own ranges, and buyers set theirs in the contract.
That said, the trade uses fairly similar bands. The figures below are typical ranges for illustration only. Confirm the exact range with your supplier and choose what suits your recipe and equipment.
Typical ranges, for illustration
- Flakes and kibbled: large pieces, often quoted somewhere around 8 to 20 mm, sometimes larger for whole flakes.
- Large chopped: often around 5 to 10 mm.
- Chopped: often around 3 to 5 mm.
- Minced: often around 1 to 3 mm.
- Granules: often quoted around 0.2 to 1 mm, or by mesh, for example in the region of 16 to 80 mesh, split into coarse and fine grades.
- Powder: commonly quoted as passing 80 or 100 mesh.
Millimetres and mesh
Larger forms are usually described in millimetres, the size of the sieve holes the product passes through or stays on. Granules and powder are usually described by mesh, the number of openings per linear inch of the sieve. A higher mesh number means a finer sieve.
Mesh numbers differ slightly between sieve standards, such as US and ISO series. State which standard your lab will use, or give the aperture in microns, so both sides measure the same thing.
How to write a size spec
A size range alone is not enough. Every milled product has some pieces above and below the range. Your spec should say how much is allowed outside it.
- Main range: for example, at least a stated percentage retained between two sieves.
- Oversize: a maximum percentage on the top sieve.
- Undersize or fines: a maximum percentage through the bottom sieve. Fines matter for chopped and minced, where dust looks poor and cakes.
- Method: sieve sizes, sample weight and shaking time, or a named lab method.
- Sampling point: tested at the plant before packing and again on the arrival sample if you wish.
Why size drifts between shipments
Flakes break during transport and handling, so a cut that leaves the plant within range may arrive with more fines. Worn or damaged sieves at the plant let oversize through. A plant short of one cut may also blend from neighbouring sizes.
Agree whether size is checked at loading or at arrival, and keep a retained sample. Our guide to writing a specification for dehydrated onion powder and the general guide to moisture, purity and foreign matter tolerances cover the rest of the limits.
How we help
We ask each processor for its sieve sizes and recent sieve analyses, then have samples checked at an NABL-accredited lab against the range you need. At loading, we draw samples for a sieve test before the container is sealed. Start with a free sourcing review.