Moisture Migration
When two different products are sealed up in some sort of packaging, they are almost guaranteed to exchange moisture. Whether the products are crackers and cheese, or gelcaps and API powder, moisture always wants to move from high to low water activity areas. Take a look at this video to understand what drives moisture migration:
Moisture migration might make a product that tastes fine, and over time, turn it into a mushy mess. As our customers who make spice blends know, if three of four spices with different water activities are mixed together, moisture migration can create lumps that are hard as rocks. These are all examples of why water activity data is so important.
If you know the water activity of your components, you know which of them will gain and lose moisture. The same isn't true for moisture content. In fact, sometimes moisture will move from the lower moisture component into the higher moisture one - only water activity can tell you if this will happen.
How can you use this information?
- Use the AquaLab 4TE Water Activity Meter to measure the water activity of your product's components. As soon as you know the numbers, you'll know which components are going to gain and lose moisture
- Use the AquaLab Vapor Sorption Analyzer to study how fast the moisture migration occurs. This instrument allows you to see how quickly different products take up and lose moisture.