Dehydrated garlic is bought and sold almost entirely on particle size, and yet particle size is the parameter most often specified badly. A buyer writes “granulated garlic” into a contract, receives something that behaves differently from the last supplier’s granulated garlic, and discovers that the word describes a region of a continuum rather than a defined grade.
This guide sets out how the grade ladder actually works, how to read and write a mesh specification, and which of the other parameters — pungency, colour, moisture, microbiology — carry real commercial weight.
The grade ladder
Dehydrated garlic is produced as a single dried intermediate and then reduced. Every grade below the first is made by milling and sieving the one above it, which is why they share every parameter except particle size and bulk density.
| Grade | Typical character | Where it is used |
|---|---|---|
| Sliced or flaked | Whole or halved dried clove slices | Visible garnish, dried soup packs, pickling |
| Chopped or kibbled | Coarse irregular pieces | Marinades, sauces where visible pieces are wanted |
| Minced | Smaller uniform pieces | Ready meals, dressings, retail jars |
| Granulated | Free-flowing, sand-like | Seasoning blends, dry rubs, snack seasoning |
| Powdered | Flour-like, low bulk density | Emulsions, brines, beverages, coatings |
The grade you choose is a decision about visibility and about hydration speed. Coarse material rehydrates slowly and stays visible; fine material dissolves fast and disappears. See particle size for the underlying concept.
How mesh numbers work
A mesh number counts openings per linear inch in a test sieve. A higher mesh number means more, smaller openings, so a higher number means finer material. This is the single most common source of confusion in the category: mesh runs backwards relative to intuition.
A grade is defined by a pair of sieves, not one. “Through 20 mesh, on 40 mesh” means the material passes a coarser screen and is retained on a finer one, so everything in the fraction sits between the two aperture sizes. A specification that names only one sieve is not a specification.
Because the mesh count depends on wire diameter as well as aperture, the authoritative reference is the aperture in micrometres, not the mesh number. Test sieve apertures are standardised in the ISO 3310 series, and a robust specification quotes both: the mesh convention the industry uses in conversation and the aperture in micrometres that a laboratory can actually verify.
The fines fraction, and why it decides your dosing
Every sieved grade carries a fines tail — material finer than the lower sieve that was not fully removed, plus new fines generated by attrition in handling and transport. The fines percentage is where most practical trouble starts:
- Fines segregate in a container. The bottom of a drum is finer than the top, so a dosing system calibrated on the first sample drifts through the batch.
- Fines change bulk density, so a volumetric doser delivers a different mass as the fines content changes.
- Fines dust, which is a housekeeping and, at high concentration in confined equipment, a safety consideration.
- Fines hydrate instantly and can form lumps in a wet application where the coarse fraction disperses cleanly.
Cap the fines fraction explicitly and state the sieve and the method used to measure it. A cap without a method is unenforceable.
Bulk density: the parameter buyers forget
Bulk density ties particle size to everything commercial. It determines how much product fits in a drum or a carton, which determines the freight cost per kilogram of active ingredient. It determines whether a volumetric doser is even usable. And it is the quickest indicator that a delivery differs from the previous one: two lots with identical sieve analyses but different bulk densities usually differ in particle shape, which shows up in flow behaviour.
Specify it, in grams per litre or the equivalent, with the measurement method stated — tapped and untapped values are not the same number.
Pungency, colour and moisture
Pungency. Garlic flavour comes from sulphur compounds generated enzymatically when cell structure is broken. Drying temperature and time determine how much of that potential survives. Pungency is specified either by a sensory panel against a reference or by an instrumental measure of the relevant sulphur compounds. Either is acceptable; having neither in the contract is not, because pungency is the whole reason the ingredient is being bought.
Colour. Specified as creamy white to pale ivory. Browning indicates excessive drying temperature or enzymatic reaction before drying, and it usually travels with a loss of pungency, so a visibly tan lot is generally weaker as well as uglier.
Moisture and water activity. Both belong in the specification, and water activity is the one that predicts behaviour. Dried garlic is strongly hygroscopic; a drum opened in a humid room and left open will pick up moisture measurably within a shift. Moisture determination for dried spices and condiments follows ISO 939.
Microbiological expectations
Dehydrated alliums are a dried agricultural product that receives no lethal step after drying unless one is deliberately applied. Salmonella absence in a defined sample is the standard requirement, and total plate count, yeasts and moulds are specified contractually. Regulation (EC) No 2073/2005 sets the criteria that bind in law; anything tighter in a buyer specification is a commercial term.
Where a buyer needs a lower baseline than good manufacturing practice delivers, a validated decontamination step — steam treatment being the common choice for a clean-label position — is applied. That step must be validated and documented, and it will affect pungency, so it is a trade-off rather than a free improvement.
A specification checklist
- Grade name plus the sieve pair, quoted in both mesh and micrometres
- Fines cap, with the sieve and the analytical method stated
- Bulk density with the method, tapped or untapped
- Moisture and water activity, with methods
- Pungency, by panel or instrument, against a named reference
- Colour, against a reference or an instrumental value
- Microbiological criteria, and whether a decontamination step is applied
- Residues and contaminants, referenced to the instruments rather than to restated numbers
- Packaging, liner specification and the food contact declaration
Write those nine and the category becomes predictable. Leave the first two vague and every delivery is a negotiation.