Coffee bean moisture content knowledge how coffee bean moisture content affects coffee roasting

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In every stage of the coffee industry chain, the moisture content of raw beans must be reduced to avoid defects and defects caused by moldy raw beans. Proper preservation can even improve the value of raw beans. Ensuring proper drying of beans is important to optimize their quality potential and minimize the possibility of problems.

The role closest to the end of the supply chain, the bean baker, has two tasks to control moisture content. On the one hand, they must maintain the moisture content of specific batches of raw beans within a precise range in order to maintain quality standards. They must keep the moisture content of coffee within this range and hope that raw beans will not be stored for more than a year, otherwise they will become old beans.

On the other hand, in a few minutes, the bean dryer applied high temperature and high pressure to drive the last remaining moisture out of the beans. In these few minutes, the coffee will be exposed to a lot of energy, which determines whether the coffee is successfully presented.

Is there an ideal moisture content?

There is no official standard for the ideal moisture content of raw beans, although the International Coffee Organization ICO recommends 11% as the standard. However, it is generally believed that 10-12% is a reasonable range. Any raw beans less than 10% may lead to a decline in coffee quality, while a higher moisture content may pose a risk of mold breeding.

However, the humidity of coffee is not static. Although the drying process in the producing area before export has greatly improved the stability of beans, the change in water content still exists. Environmental factors, such as particularly humid or hot places, are common causes of this situation.

Roast coffee with high / low moisture content

There are many factors in the baking process, and it is difficult to define the baking result through only one factor, such as water content. However, through a solid grasp of the basic principles of the baking process, coupled with accurate and consistent moisture content readings, we can clearly judge what baking techniques should be used and develop our own response process.

The beginning of the baking process involves accumulating enough heat and pressure in the bean baking machine to remove moisture from the beans at the beginning of the baking process. Due to the lack of better terminology, this stage is often referred to as "dehydration." No really important chemical reaction takes place at this stage; on the contrary, when the moisture is expelled, the pressure in the pot begins to increase, creating the conditions needed to bake the coffee. "

If you want to bake coffee with a high moisture content, you need to apply more heat at this stage. There are three options: preheat at a higher temperature (but do not scorch the outer layer of the coffee beans), use a higher temperature during the dehydration stage, or extend the dehydration period.

But there are still some ways to explore, and if your goal is to achieve consistency in dehydration time, a higher temperature preheating boiler is recommended at first. "if the beans have a high moisture content, the more calories they can retain and the better the heat transfer, so they can be baked with more heat at the beginning. "