How Do Moisture Analysers Work?
A moisture analyser, also known as a moisture balance, is a machine that calculates the moisture content of a sample. Scaletec stocks Adam Equipment’s PMB Moisture Analyser. This blog will discuss how moisture analysers work, how you can use one to test your samples and how moisture analysers improve upon traditional oven testing.
How Do Moisture Analysers Work?
Moisture analysers are a scale/compact oven combination. Those like Adam’s PMB calculate moisture content with the Loss on Drying (LOD) method. Essentially, after the initial sample weight is taken, the analyser will quickly heat up the sample, providing regular weight reports, until there’s no more moisture left. Then, it automatically weighs the sample again. Using the difference between the initial and final weights, the PMB calculates how much moisture is in the sample. Your result is provided as a percentage on the display – e.g. 23.6% moisture.
How Do I Use a Moisture Balance?
To use a moisture balance, you’ll need to properly prepare your sample, choose the right heat and drying settings, and select your testing time and intervals.
Sample Prep
The pan on the PMB Moisture Analyser measures 100mm ø and can hold between 50g and 200g depending on the model. In many cases your sample will need to be a representative portion of a larger item – such as a slice or chunk of cheese from the middle of a cheese wheel.
The sample should cover an even layer on the pan. Grind up solid samples, like seeds, so the particles are small and consistent. Pastes and liquids should be spread evenly. You should have a smooth, consistent layer on the pan before heating. This helps guarantee the sample dries evenly and prevents burning or splattering.
Choosing Type of Test
Moisture analyzers are primarily for testing moisture, but that’s not the only tests the PMB can perform. Adam’s PMB offers four different types of tests:
- Determining moisture percentage
- Determining solid percentage
- This is the other side of the coin to moisture percentage. Instead of the test showing 23.6% moisture in a sample, the result would be 76.4% solid.
- ATRO Moisture
- Provides how much moisture there is in a sample compared to dry solids
- ATRO Solids
- Compares the sample's total weight (solids and water) to the dry mass
Choosing Heat Settings
Adam’s PMB Moisture Analyser boasts three different heat settings:
- Single temperature
- Heat the sample to a set temperature
- A quick option ideal for stable, uniform samples that can withstand constant heat
- Ramp to temperature
- Slowly increase heat over a set time until it reaches your set temperature
- Used for samples that could degrade if exposed to high temperatures too soon
- Step temperature
- Set up to three different temperatures for different lengths of time
- Used for samples that aren't uniform, with different components that could degrade at different heats and times
Selecting Testing Time & Intervals
Next, you would set how long you want your test to go for – it can be anywhere from a few seconds to 99 minutes, depending on the sample. Dryer samples will likely take less time than paste or liquid samples.
If you’re not sure how long it will take to deplete the moisture from your sample, you can set intervals. Intervals are set times your PMB will compute and print results throughout the heating process. You can set your analyser to automatically stop the test when it no longer detects a change of weight in your sample – which would mean there’s no more moisture to remove, and thus no reason to continue heating.
Tests can stop in three ways:
- When your set time has passed
- When weighing results are stable, indicating no more moisture
- A combination of both - whichever comes first
These settings give you an incredible amount of control over your testing, so you can get the exact results you need.
Save Your Recipes and Test Results
When you finally find the right heat, time and interval settings for your samples, it can get tedious inputting them repeatedly. Adam’s PMB Moisture Analyser allows you to save up to 49 test procedures/settings in its memory, along with up to 99 testing results. Simply follow through the instructions to store your recipe and give it a numeric or alphabetic name for recall later.
Why Perform Moisture Analysis?
There are countless reasons to perform moisture analysis, but we’ll focus on three:
Food & Cosmetics
Moisture balances are often used for quality control purposes. During the product development process, especially for food items and cosmetics, moisture content is extremely important. Too much moisture can lead to the spread of bacteria and the growth of mould, while too little moisture can make items hard and brittle. No one wants to break a tooth on a biscuit or have their hand lotion dripping down their arm.
By testing small portions of a product regularly, quality control specialists can guarantee the moisture content is both right on target and consistent. If not, moisture tests are quick enough that you can pause production to perform more in-depth testing on the whole batch before it goes further in the manufacturing process.
Agriculture
Regularly testing both seeds and soil for moisture can help improve agricultural processes as well. Seeds that have too much moisture, such as after leaving them in the rain, may begin to germinate prematurely, before you plant them. Or, even worse, begin to mould. Seeds with too little moisture may use up their internal nutrients and desiccate, meaning they’re no longer viable for planting. This can interfere with farming schedules and risk crop income!
Regularly testing stored seeds with a moisture analyser can help guarantee they’re being kept in a safe environment, so they’ll grow when they’re planted and no sooner!
Soil should also be tested regularly. This can help determine how long the soil maintains moisture over time, so farmers know exactly how much and how often to water their crops for the best yield. Adam Equipment has an excellent blog delving into the topic more deeply.
Pharmaceuticals
Moisture content in pharmaceuticals is extremely important, especially given that many medicines are designed to dissolve once in contact with moisture in the body. They can lose their efficacy when moisture levels aren’t ideal – making it crucial to perform extensive, detailed quality control on pharmaceuticals.
How Are Moisture Analysers Better Than Traditional Ovens?
Traditionally, moisture analysis is performed with a separate scale and oven. The sample is weighed on the scale, then baked until dry and weighed again. While traditions have their merit, Scaletec has leaned into the more modern and efficient method of moisture determination with moisture analysers.
Smaller Samples & Faster Tests
Ovens work by circulating air through the chamber, which provides inconsistent air flow throughout and requires a large sample size for proper heat distribution. Completely drying one batch of samples can take as long as twelve hours.
Adam’s PMB moisture analyser requires only a few grams of a sample, heating them up to dry in just minutes. Save yourself a full half day!
More Reliable Results
Because ovens don’t have built in balances, there’s no way to check in on your samples during the heating process without taking them out of the oven, which loses heat and disrupts the process. However, if you don’t check in on your samples, you risk burning them by accident. A double-edged sword!
Moisture analysers reweigh at regular intervals, ensuring your test ends as soon as you have the results you need. Plus, with the machine itself calculating your results, there’s no chance of human error from manually performing the moisture calculations.
Long story short, moisture analysers like Adam’s PMB are a fast, reliable and efficient way to test samples for moisture content. Add the PMB to your cart today!