Moisture balances are a fast and accurate direct method of moisture determination, compared to an oven test, which can take many hours to complete. A moisture balance also weighs and heats a sample simultaneously, reducing errors caused by moisture evaporation during transport and weighing. Different types of heat sources, and advanced software, offer extreme versatility in exploring a samples drying characterisitics. Many coffee related products, because of their dark color, which absorbs more heat, and because they contain evaporative oils and compounds, must be carefully prepared, and even more carefully scrutinizedwhen conducting a test for moisture determination.
Every material has unique thermal emission and absorption characteristics.
Emissivity is a measure of the efficiency in which a surface emits thermal energy. It is equal to the amount of thermal energy it can absorb, once temperature equilibration has been attained.
A black body is a material that is a perfect emitter of heat energy and has an emissivity value of 1. Coffee is in the range of .7 to .9
Here you can see a halogen (Short Wave ir), on the left, and next to it an IR Emitter Heat Source (Mid Range IR), on the right. There is a visible difference in the brightness of the light. The IR Emitter Heat Source, is used for coffee application, as it speeds up the process.
SAMPLE SPECIFIC HEAT SOURCE
3 CHOICES AVAILABLE:
HALOGEN - SHORT WAVE IR (EXAMPLE:SUGAR)
IR EMITTER- MID WAVE IR(BEST FOR COFFEE / TEA)
METAL- LONG WAVE IR(FOOD APPLICATIONS THAT SPECIFY NO GLASS)
When using a moisture analyzing balance, care has to be taken to ensure it is equipped with the most efficient heat source.