Many people who love coffee in the world, must be familiar with “grinding” terms. Yes, it is one of the most important processes for having an appropriate taste of coffee. But how does it affect the flavor of the coffee? Here’s the explanation.
The coffee beans are ground also known as “milling”. The grinding process strongly affects the brewing process. Brewing methods that expose the coffee ground to heated water, require a coarser grind than faster brewing method. Beans that are too finely ground in the heated water, the surface will be exposed too much and eventually produce a bitter, harsh, “over-extracted” taste. On the other hand, an overly coarse bean will produce a weak coffee unless you use more of it.
For your information, ground coffee deteriorates faster than roasted beans because of the greater area that exposed to the oxygen. Now, many coffee drinkers grind the beans themselves to control the quality and freshness of the coffee.
There are four methods of grinding coffee for brewing, such as:
- Burr-grinding uses two wheels or conical grinding elements, which the coffee beans are crushed with little frictional heating. The process of that releases the coffee’s oils which more easily extracted during the infusion process with the hot water. The oil gives the coffee a richer and smoother taste.
- Chopping, coffee beans can be chopped by using blades rotating at high speed (20,000 to 30,000 rpm) either in blade the coffee grinder (เครื่องบดกาแฟ )specifically designed for coffee or home blender. This kind of device is more cheaper than the burr-grinder. But the grind is not uniform and produces varying sizes of particles. Moreover, the particle will get smaller and smaller makes it difficult to get a consistent grind from batch to batch. They also create “coffee dust” that can clog up sieves in espresso machine or frech press.
- Pounding, pounding the beans using mortar and pestle can pulverize the coffee finely enough.
- Roller grinding, the beans are ground using pairs of corrugated rollers. It usually produces more even size distribution and heats the ground coffee less than other grinding methods. However due to their size and cost, only commercial and industrial scale coffee producers use this kind of method.