# CSC Scientific Blog

A while ago on these pages I agonized about loss-on-drying moisture analysis . As you may recall, my explorations of the drying process overwhelmed me with evaporation concepts , vapor pressure notions, water content complexities and water activity witchcraft, all just to dry something.

One quiet night, I was musing over moisture analysis and how easy it is to do using loss-on drying. Little did I know what was in store.

Last week, as I was reflecting on a recent moisture content problem, I recalled our series “Loss-on Drying and Other Moisture Mysteries.” In that series I examined moisture chemistry in products. However, I did little to define moisture content.

Regularly I’m asked the question; “How accurate is this moisture balance?”

The questioner asks for the answer in terms of percent (%) moisture. When I answer “it depends”, I always get the unspoken response, “Why did I ask this stupid idiot?

# Absolute Measurement

When you ask about the accuracy of something like weight or temperature the answers are straight forward and relate to the instruments' precision. For example 25 grams or 50 degrees plus or minus (+/-) 0.1 gram or 1/2 degree.

# Percent is Relative

When you ask the question of how accurate is my percentage reading, the answer becomes complicated. It’s complicated because percentage (%) is a relative term. For example, the answer for the result of a Loss on Drying (LOD) moisture test, is based on the size of the sample you use.

Using the example of a LOD moisture test we can understand the concept. The result of this type of test is calculated by subtracting the weight of the sample at the end of the test from the weight of the sample at the beginning of the test. This difference is divided by the initial weight of the sample. This procedure produces a % moisture result.

# Sample Size

In the following analysis, the implication s of sample size and instrument precision will be illustrated. This will be based on a sample that has 23.5% moisture and an electronic LOD moisture balance that has a sensitivity of 0.001 grams and repeatability of ± .005 grams.

# Sample Analysis

Moisture content is a critical factor to consider in the food industry. The amount of water in a product affects the product’s texture, shelf life, ease of processing, and cost to produce. Snack foods, baked goods, pet food, and dried goods are just a few examples of products that are vulnerable to moisture content issues like these. In many cases, an easy loss-on drying (LOD) test will allow you to monitor the moisture content of these products. (See the 3 Easy Steps to Run a LOD Test here.

Simple moisture analysis can be all it takes to improve the quality of your product. Let’s take a closer look at how moisture content affects each of these four product and production aspects.

One quiet night, long ago I was musing over moisture analysis and how easy it is to do using Loss-on Drying (LOD). Little did I know what was in store.

Five years ago, we published an article on in-line vs. off-line moisture measurement. At that time we debated whether these measurement systems should be called on-line or in-line. We chose to use the term "on-line". Since then, however, the world of the internet became known as "online". So, to avoid confusion, we changed our view and now refer to direct measurement as "in-line" moisture measurement.

A question we get a lot is:

## “How do I determine the moisture in my product?"

Of course, the answer is often “it depends”, and the method does depend on the chemical and physical composition of the product. There are several methods used to determine moisture content: Loss-on-Drying (also known as Weight Loss), Karl Fischer, NIR, and Radio Frequency.

I am very excited about a new update to the CSC Digital Moisture Balance.  To give you a perspective of why I’m excited about this Moisture Content Analyzer update, I thought you my be interested in the story of the transition from a classic mechanical moisture analyzer to the current highly robust and durable electronic instrument of today.

As you know the Karl Fischer Method of moisture analysis has a reputation of being water specific. The method works through the use of a special Karl Fischer Reagent.