What is the moisture content of coffee beans? how to test the water content of coffee beans?

Professional coffee knowledge exchange more coffee bean information please follow the coffee workshop (Wechat official account cafe_style)

The moisture content of coffee beans is very important for high-quality coffee. It will not only affect the taste of coffee, the way it is roasted, but also affect the income of coffee farmers.

Water content of coffee:

Although green beans may feel dry before baking, they still contain moisture. Any amount of liquid in a solid substance that is diffusing can be counted as water content.

After picking, typical, unprocessed ripe coffee cherries should contain about 45-55% moisture, and then reduce their moisture content to 10-12% by processing and drying. Although the treatment of green beans also includes "re-wetting", this does not increase the moisture content of green beans, as they still need to be re-dried before bagging.

According to the international coffee organization ICO, the moisture content of dried green beans should generally be between 8 and 12.5%, except for special coffees with traditionally high moisture content, such as Indian espresso. But this does not mean that a moisture content of 9% is an ideal moisture content for professional coffee.

Coffee with good water content can get higher cup score, balanced acidity and richer aroma. The standard of optimum water content is still controversial, but 10-12% is generally accepted as the most moderate water content. Many people prefer 12%, while international manufacturers are advised to set a target of 11%.

No matter what the final percentage is, if the moisture content is stable, green beans can retain moisture before baking. During transportation, climate change may lead to further water loss, but unless Rain Water drops on the bagged coffee, it will not have much impact. Unfortunately, although large companies or governments have invested a lot of technology and money at this critical stage of the coffee trade, it is still an uncontrollable factor.

Calculation of moisture content of coffee

Three basic control points need to be set up to ensure that moisture content readings are correct, including accurate quantities, accurate temperatures and accurate instruments.

Exact quantity: the same weight of coffee should be tested each time the water content is measured. If you live on coffee or often bake coffee, you may need a lot of accurate scales.

The consistency and accuracy of the temperature of the measured environment and the consistency and accuracy of the sample temperature are also important. Many instrument companies, such as Shore Measuring Systems, automatically correct the ambient temperature, so the reading should not be affected whether the environment is warm or cool. If in doubt, please choose a cooler environment to measure. "if you really care about quality, you would recommend taking measurements at lower temperatures," Fred said. "

In addition, if there is a significant difference between the sample temperature and the measured room temperature, Fred warning will encounter the problem of "sample surface moisture does not condense as expected". Therefore, it is best to wait for the measured sample to rise or fall to the same temperature as the room temperature before the measurement.

Of course, the accuracy of the instrument is also very important. If the reading of the instrument is always inconsistent with the figures provided to you by the raw bean merchant, it is necessary to check the accuracy of the instrument. "most manufacturers will provide you with samples or substitutes for determining moisture content, which can be used to calibrate your instrument," Fred said. "

Finally, it is important to consider how to sample and measure the frequency. Andres, a bean baker at Endorphin Beans, says his team checks the moisture and density of raw beans before each baking, as well as just before getting samples, before shipping and when they get them. "

As for where to take samples? It is best to take it directly from the batch. Samples taken from batches and stored separately will almost certainly dry in different ways, losing their accuracy as samples. If your bean dryer can bake more than one bag of coffee at a time, Fred recommends taking samples from each bag you want to use, then distributing them and measuring them.

The moisture content of coffee beans is an important index to ensure the quality of raw coffee beans. It is difficult to set this index. Too high and too low moisture content will affect the quality factors of raw coffee beans in the process of transportation.

END