According to the International Coffee Organization some 1.6 billion cups of coffee are consumed per day worldwide. Your local supermarket shelves and the “prestige” brands served in coffee houses confirm that coffee is a very competitive commodity. A label’s continued success with fickle customers depends a great deal on consistent quality. The correct moisture content of coffee is part of the quality quotient; this is confirmed by a moisture analyzer.Optimum moisture content is set by industry standards and will differ as coffee moves through processing steps from green beans to roasted beans to ground and instant coffees. For example, the Coffee Research Institute states that before being shipped green coffee beans must have a moisture content of 11 to 12% from approximately 60% as picked. This helps avoid spoilage. Initial drying is typically done on patios at the coffee plantation then beans are transferred to mechanical dryers. Moisture content is determined by moisture meters.
As coffee moves through its various processing stages the moisture content of random samples should be confirmed on a regular basis by using a compact, precision moisture analyzer such as the Kern MLB available from Tovatech. These units combine a precision analytical balance with a halogen heater. They operate on the thermogravimetric principle controlled by a programmed procedure to determine loss of weight on drying (LOD). Moisture analysis procedures for each processing stage have been developed by researchers to yield fast, accurate and reproducible results based on optimum heating profiles involving time, temperature and how rapidly the temperature is increased. The latter is exemplified by standard, soft, fast, or step drying.
An Example of Moisture Analysis for Ground Coffee
Industry standards specify the proper moisture content for ground coffee. Here is an example of how a moisture analyzer can be used to confirm the moisture content.
- Place 2 grams of fresh ground coffee on the sample plate of the moisture analyzer and record the weight.
- Program the moisture analyzer by setting its operating criteria, for example a drying temperature of 150 C.
- Place the sample plate into the moisture analyzer sample plate holder and close the cover. The cycle begins automatically.
The unit’s display panel continually updates the status of the process. The analysis automatically terminates when drying is complete and the dry weight is stable, or after a fixed time specified by the operator or manually. For record keeping the data can be transferred to a printer or PC via an RS 232 interface.
Because ground coffee can absorb moisture from the atmosphere a moisture analysis should be made periodically during final packaging operations.
Moisture analyzers are also used to confirm the moisture content of other beverages such as tea and powdered milk in accordance with government and industry standards. The versatile instruments are indispensable as a quality control tool across a broad range of industries.
Contact the scientists at Tovatech for information on how a moisture analyzer will help your company’s quality control procedures.
