Caking and Clumping

Caking and clumping may not sound like a huge problem, until a hopper full of milk powder seizes up and shuts down your production line.  So what causes problems like this to happen?

The story of caking/clumping goes like this: when powders are exposed to moisture from higher water activity ingredients or humid air, they take on water vapor.  At first, the water just sits on the surface of the powder particles, and everything's fine.  Powder still flows smoothly, and for a while, taking on moisture isn't a problem.  Soon, though, the water begins to penetrate into the center of the particles, and they get "sticky".  At this point, the powder isn't free-flowing, and manufacturing becomes a mess.  

Irradicate caking and clumping issues by using these steps:

- Control plant humidity.  Air at a higher humidity than the water activity of your powder will always make "wetter".  Keeping humidity low will prevent water from sticking to your powder.  

- Use a water activity meter to know whether you're going to have a problem.  A water activity meter will tell you what your powder's aw is.  If it's lower than your room humidity, you know you're going to have some moisture migration.  

- Use a Vapor Sorption Analyzer to know what water activities will cause clumping problems, and how long it takes for your product to take on moisture under various conditions.  The Vapor Sorption Analyzeer can make a curve that pinpoints the water activity above which caking and clumping occur.  Once you know this number, you can study (for example) the amount of time it will take for your powder to reach 0.45 aw if room humidity is 60%.   See the graph below for an example of how isotherms can help you predict problems with your product: