Making a good cup of coffee at home is a very interesting thing, but it also takes some time on additional simple steps, such as using water at the correct temperature, weighing coffee beans, and grinding coffee beans on site.
After purchasing coffee beans, we need to go through a step before brewing, which is grinding the coffee beans. During the grinding process, coffee beans can generate sufficient surface area, which can further release the flavor of coffee during brewing.
Grinding degree of coffee powder
Generally speaking, the degree of grinding of coffee beans can be roughly divided into the following categories:
(1) Coarse Grinding: The coffee particles ground are similar to the coarse white sugar.
(2) Medium grinding: particles of the same size as a mixture of sugar and coarse white sugar.
(3) Fine Grinding: The coffee ground is close to a powdered form, similar in thickness to powdered sugar.
Some people also divide the degree of grinding into more detailed categories, such as “medium” divided into “medium to coarse” and “medium to fine”. But the main methods are still rough grinding, medium grinding, and fine grinding.
Coffee brewing utensils suitable for different levels of grinding
The degree of grinding is usually determined by the brewing method. The production requirements for different flavors of coffee vary. If the brewing time is short, the ground powder must be finer. The required fineness of coffee powder varies depending on the brewing tool used.
Rough grinding is generally suitable for French pressed coffee, as the French press pot uses the most direct method, soaking and filtering, allowing oil and aromatic substances to pass through the filter.
Medium grinding is suitable for hand brewed coffee as well as siphon coffee. Because the extraction time of a siphon pot is generally around 1 minute, if the coffee powder is too fine, not only will it be over extracted, but it will also cause the coffee liquid to clog the conduit during reflux; If the coffee powder is too coarse, it will cause aromatic substances to remain hidden inside the particles and unable to release fragrance, so medium ground coffee powder is the most suitable.
Fine grinding is suitable for Italian espresso. In the extraction process of the Italian machine, coffee powder needs to withstand high pressure and high temperature, so it needs fine powder, and powder can be evenly extracted after compaction. Similarly, finely ground coffee powder is also suitable for traditional Türkiye coffee.
Factors affecting the degree of coffee grinding
1. Coffee powder contact area
The influence of grinding size is related to the relatively small physical processes that occur during the brewing process.
When water tries to extract those flavors from individual coffee particles and pour them into your cup, it cannot magically transport them to the center of the coffee grounds. It must start from the outside of the coffee granules and wash away the soluble coffee solids first.
Assuming you have a coffee granule, then cut it in half. The total amount of coffee you have left is the same, but now the surface area inside the particle is larger, and water can immediately enter it. The more fragments you divide coffee particles into, the more surface area will be exposed (while the total mass of coffee remains constant).
Therefore, in any brewing method, finer coffee grounds are extracted faster, while coarser coffee grounds are extracted slower.
2. Coffee grinding resistance
If you take out two batches of coffee, and one of them is finer than the other, the arrangement of these coffee particles will be different.
Suppose you fill one test tube with rocks and another with sand. If you try to pour water into rocks, the water will quickly flow down because there will always be large gaps between the rocks; However, the gaps between sand particles are very small, and the water flow requires more time. The same thing may happen when you pour or especially change the grind size in espresso. If ground too finely, it will not only provide more extraction efficiency, but also slow down the flow rate and increase the total time (which will also increase extraction efficiency)
The lower the percentage of brown substance extracted from the coffee grounds in the cup, the stronger the acidity of the coffee. The higher the percentage, the more bitter it is. Therefore, if the taste you pour out is too bitter, you can add a little rougher and repeat all other steps, which will be helpful. If your French pressed coffee has a too sour taste and lacks a lot of sweetness, then crush it into smaller pieces for a more balanced flavor.
Each type of coffee is different, so adjusting the corresponding grinding size is a crucial step.
Post time: Nov-05-2024