Agglomeration and solubility
How agglomeration improves instant coffee’s solubility, the science behind it, and why it matters for consumer experience.
- Coffee Basics Nerds
- 1 min read
Article 7 of 12 in Decaffeination & Soluble Coffee/
Solubility in Instant Coffee
- Instant coffee must dissolve quickly and evenly in hot water.
- Spray-dried powders are often too fine, leading to clumping or uneven dissolution.
- Agglomeration is used to modify particle size and improve solubility.
What is Agglomeration?
- Process of clustering small coffee particles into larger, porous granules.
- Achieved by lightly re-wetting spray-dried powder so particles stick together.
- Drying locks granules into a stable form.
Benefits of Agglomeration
- Improved Dissolution: Larger granules dissolve more uniformly.
- Reduced Dustiness: Less mess during packaging and preparation.
- Enhanced Appearance: Chunkier granules look more appealing to consumers than fine powders.
- Controlled Bulk Density: Easier to dose consistently by spoon.
Solubility Factors
- Porosity: Agglomerated granules allow water to penetrate quickly.
- Moisture Content: Must be low enough (<4%) to ensure shelf stability while maintaining solubility.
- Particle Size Distribution: Consistency ensures predictable preparation.
Market Applications
- Agglomeration used widely in mainstream instant coffees for user convenience.
- Premium freeze-dried instants usually skip this step since they naturally form chunky, soluble granules.
Summary
Agglomeration clusters fine coffee particles into larger, porous granules that dissolve faster, look better, and handle more cleanly. This step enhances solubility, convenience, and consumer appeal, especially for spray-dried instant coffees.