Particle size, mesh, and segregation: why powder blends come apart

You can blend a powder perfectly and still end up with units that are wrongly dosed — because the blend came apart again before it was filled. Segregation, where a mixed blend separates back out, is one of the quiet enemies of content uniformity, and it's driven largely by particle size. Ingredients of very different particle sizes don't stay mixed. Understanding particle size, mesh, and segregation is key to blends that hold together. Here's how it works.

Particle size and mesh

Particle size is what it sounds like — how big the particles of a powder are — and it's often described by mesh, the sieve size particles pass through. A fine powder has small particles (high mesh number); a coarse one has large particles. Each ingredient in a blend has its own particle size, and how those sizes compare across ingredients turns out to matter a great deal for whether the blend stays mixed.

Why mismatched sizes segregate

When ingredients have very different particle sizes, they tend to separate. During handling, vibration, and flow — moving the blend, filling capsules — smaller particles sift down through gaps between larger ones, and different sizes settle differently. The result is segregation: a blend that was uniform separates so that some portions are rich in one ingredient and poor in another. Fill capsules from a segregated blend and the dose varies unit to unit, even though the overall blend was correct.

It's a uniformity problem in disguise

Segregation is especially dangerous because it can happen after a good mix — the blend passes a uniformity check, then segregates on the way to filling. So a product can look fine in the blender and be non-uniform in the bottle. This is why particle size matching matters: a blend whose ingredients have similar particle sizes resists segregation and stays uniform from mixing through filling.

Designing around it

Formulators manage segregation by matching particle sizes across ingredients where possible — specifying a mesh size for each, milling a coarse ingredient finer, or granulating to make particles more uniform. Sometimes a binding or granulation step locks the blend together so it can't segregate. The point is that particle size is a specification worth setting deliberately, not an accident of whatever the supplier shipped. Matching sizes is designing for uniformity.

Particle size is part of the ingredient spec

Because particle size affects uniformity (and also flow, dissolution, and taste), it belongs in the ingredient specification — the mesh or particle size you require for each material. Holding that as part of each ingredient's data means the formula carries the information needed to anticipate segregation risk and to specify what to buy. Particle size becomes a managed property, not a surprise discovered when units fail a uniformity test.

This is general information, not regulatory or legal advice. Confirm particle size, uniformity, and process requirements for your specific product with your manufacturer before relying on a general summary.

Where Lemoniq fits

Lemoniq lets particle size and mesh sit in each ingredient's specification, so the data needed to anticipate segregation and specify what to buy travels with the formula — making particle size a managed property of the BOM rather than an accident discovered at filling.

The takeaway

Mismatched particle sizes cause a mixed blend to segregate — separating so units get the wrong dose, sometimes after passing a uniformity check. Matching particle sizes, specifying mesh per ingredient, and treating particle size as part of the ingredient spec is what keeps a blend uniform from mixing to filling.

Lemoniq holds particle size in your ingredient specs, so segregation risk is managed, not discovered. See how it works