Knowledge Base
Moisture sorption isotherms
Isotherms allow you to identify where caking and clumping occur, predict the effect of formulation changes, determine the best packaging, evaluate the kinetics of moisture, and more.
Water activity for safety and quality
Water activity’s usefulness as a quality and safety measurement was suggested when it became evident moisture content could not adequately account for microbial growth fluctuations. Water activity is a measure of the energy status of the water in …
Water activity controls microbial growth
If you measure the water activity of any material, you will know which bacteria, molds, or fungi can grow on and in it.
Water activity definition
Water activity is derived from fundamental principles of thermodynamics and physical chemistry. As a thermodynamic principle, there are requirements in defining water activity that must be met. These requirements are: pure water (aw = 1.0) is the …
Lowering water activity with humectants: a step by step guide
Step-by-step guide to lowering water activity using humectants. Predict final water activity before mixing the first batch.
Predict moisture migration with water activity
Water activity, not water content, predicts how water will migrate within a product. Knowing the water activity of discrete ingredients can help determine how to process them.
Introduction to water activity
Water activity is directly related to the microbial susceptibility of food products and is correlated with many of the reactions that end shelf life in foods. Learn more about the science that makes water activity measurements so powerful.
Using hurdles for safer, fresher food
Over-processing food products can cause losses in taste, texture, and ultimately, profit. Hurdles allow milder forms of food preservation while keeping products safe.
Use water activity to get—and maintain—the right texture
There is an ideal range of water activity–a sweet spot–that maximizes texture and quality. When texture is important, water activity is the most powerful way to measure and monitor moisture.
Three steps to eradicate caking and clumping
Powders exposed to moisture take on water vapor, stop flowing, and manufacturing becomes a mess. These 3 simple steps will prevent caking and clumping.
How to control lipid oxidation
Because water activity is a measure of the energy of water in a product, it affects how quickly lipid oxidation reactions proceed.
Six sample preparation best practices
Correct sample preparation will yield more consistent and reliable water activity readings.
How water activity and pH work together to control microbial growth
Water activity and pH work synergistically, with their combined effects being more powerful at control than their individual effects.
Measuring moisture content: It’s more complicated than you think
While moisture content is simple in theory, it is actually a difficult and complex process to obtain an accurate, repeatable measurement. Here’s why.
Predict packaging performance to maximize product shelf life
Water activity is derived from fundamental principles of thermodynamics and physical chemistry. As a thermodynamic principle, there are requirements in defining water activity that must be met. These requirements are: pure water (aw = 1.0) is the …
Water activity and pharmaceuticals
Water activity measures the energy status of water in a product. Energy status is a better way to predict and evaluate moisture-related reactions that damage pharmaceutical products
Water activity: a better moisture metric for pet food
Find the ideal water activity range for your pet food product that maximizes profit, nutrition, and tastiness while keeping it safe from microbes and mold.
Water activity and seeds
Seeds stored at the correct moisture remain viable for years. Water activity is the best way to define and monitor safe storage conditions for seeds.
Water activity: an extra barrier to microbial growth in sauces and dressings
Water activity can act as a secondary hurdle to microbial growth in sauces and dressings, allowing gentler forms of preservation.
Water activity and tobacco
Water activity offers a better way to measure moisture during the curing of tobacco and allows QC/QA to deliver a more consistent product.
Water activity: a better way to monitor moisture in plastics
If plastic parts are injection-molded with resin that has too much moisture in it, ugly-looking or brittle parts can result. Water activity may help solve this problem.
Measure moisture right in cereal and grain-based products
There is a common misconception that low-moisture foods are safe because they don’t support the growth of microorganisms. Recent events have proven this assumption wrong.
Solve moisture problems in powders and spices
Controlling water activity can stop caking and clumping by identifying water activity levels that cause problems.
Water activity for monitoring the quality of dried distillers grain
Ethanol producers can boost efficiency, save money, and ensure the quality of their product by using water activity.
Karl Fischer vs. water activity in pharmaceuticals
Simply knowing the total amount of water by Karl Fischer may not be the most effective method for understanding the effects of water on safety and stability. Water activity is an alternative water measurement that provides essential information …
Measuring water activity in nuts and dried fruit increases quality and profits
For nuts and dried fruits, moisture mistakes are painful–too much water means mold, too little means lost profit and quality issues.
Water activity in snack foods
Measure water activity to know whether or not your snack food product is safe–and to set specs that solve texture and lipid oxidation problems.
Water activity and processed meat
The beauty of water activity is that you actually know when it’s done–done right–and you can dry to that exact point every time.
Government regulations recommend the use of water activity
The growing recognition of measuring water activity is illustrated by the U.S. Food and Drug Administration’s incorporation of the water activity principle in defining safety regulations. We’ve provided a reference to U.S. government safety …
Water activity in candy and confectionery
Getting the moisture measurement right is critical for nearly every confectionery product. Water activity is the most powerful way to measure and monitor moisture in candy and confectionery
Calculating the change in energy
Learn to calculate the change in energy that accompanies a change in vapor pressure using the first law of thermodynamics.
Water activity: a better moisture metric for coffee and tea
Products like tea (1-2% moisture) have so little water in them that loss-on-drying methods aren’t very precise. Water activity can give a lot more information.
VAPOR SORPTION ANALYZER cited publications
List of scientific publications where the VAPOR SORPTION ANALYZER was used to obtain moisture sorption data.
PaWkit/Lite cleaning video
Watch this video to learn how to clean your PAWKIT or LITE water activity meter.
AQUALAB cited publications
List of scientific publications where various types of AQUALAB water activity meters were used to obtain water activity data.
AQUALAB 4TE Certification
Become an AQUALAB 4TE certified user by watching this 15 minute training video and passing the certification test with a score of 80% or better.