Mesh is the least discussed number on a gellan gum specification sheet and one of the most practical. It decides how fast the powder wets out, how much dust your operators breathe, and how likely you are to get lumps.
What mesh actually measures
Mesh is a particle size grade based on a sieve with a defined number of openings per inch. A higher mesh number means smaller openings and finer powder.
| US mesh | Approximate opening | Typical character |
|---|---|---|
| 40 | 425 µm | Coarse, free-flowing, dusty least |
| 60 | 250 µm | Medium coarse |
| 80 | 180 µm | Medium |
| 100 | 150 µm | Medium fine |
| 140 | 106 µm | Fine |
| 200 | 74 µm | Very fine, fast hydrating, dustiest |
| 325 | 44 µm | Ultra fine, usually only for special cases |
Real products are not a single size. A supplier quoting "100 mesh" normally means the powder passes a 100 mesh sieve, which is a statement about the top end of the distribution only. Always ask for the full particle size distribution — usually as D10, D50 and D90, or as a set of sieve fractions.
Why grind size matters so much
Gellan gum must be dispersed in water before it will hydrate, and hydration only happens at temperature. Particle size controls the first part of that sequence.
- Finer powder has far more surface area. Water reaches the particles quickly, so hydration is faster and more complete at a given temperature and holding time.
- Coarser powder wets more slowly but is much easier to disperse. Individual particles stay separate long enough for shear to spread them through the liquid.
The failure mode differs in each direction:
| Problem | Likely cause |
|---|---|
| Lumps and fish eyes | Powder too fine for the dispersion method used, or added too fast |
| Slow, incomplete hydration | Powder too coarse, insufficient time or temperature |
| Gel strength below expectation | Partial hydration leaving undissolved particles |
| Excessive dust, operator irritation | High fines content |
None of these can be fully corrected downstream. If your plant cannot apply high shear at the point of addition, choosing a coarser grade is often the cheapest fix available.
The interaction with your dispersion method
Particle size and mixing method must be chosen together:
- High shear, hot water, good agitation — a fine grade (150–200 mesh) performs well and hydrates fast.
- Low shear, cold-to-warm water, manual addition — a coarser grade, or an agglomerated grade, is far more forgiving.
- Dry blending with sugar or a salt carrier — the carrier does most of the dispersion work, so a finer grade becomes viable again.
Mesh versus "instant"
Agglomerated (instant) grades are a separate approach rather than simply a very fine grind. The particles are built up into porous clusters so that water can penetrate between primary particles instead of forming a gelatinous skin. The result is a powder that disperses without high shear, at the cost of a higher price and often a lower bulk density.
What to put in your specification
A particle size specification that actually protects you should include:
- D10, D50 and D90, or defined sieve fractions with tolerances
- A limit on fines, if dust is a safety or handling issue
- Bulk density, because it determines hopper and feeder behaviour
- A defined dispersibility or hydration test, not just a size measurement
If you have ever had two lots of "the same" gellan gum behave differently in a mixing tank, particle size distribution is one of the first things worth comparing. It is quick to check and it is often overlooked.
For supply of gellan gum (E418) in multiple mesh grades with full particle size data, contact Cinogel.
Part of the E418.org gellan gum knowledge base.