Which one can make coffee extraction more even, swirling or stirring?

To ensure that coffee grounds are evenly extracted, the two most common methods are swirling and stirring. But which one is better?

The main purpose of stirring and rotating is to improve the moisture distribution between the coffee powder, which can reduce the channeling effect and the resistance of large particles. Uniform extraction will make the coffee taste better. Under-extracted coffee is usually sour, and over-extracted coffee is bitter and astringent.

"Steaming" is not steaming as we think, it is actually the first stage of extraction. After the water contacts the coffee powder, the coffee powder begins to release carbon dioxide. If you want to extract evenly, you need to ensure that these gases are fully released.

So you can stir during the steaming process so that the coffee powder at the bottom of the filter cup can fully absorb water. But it should be noted that the stirring should be fast, otherwise it may become a paste. Steaming makes the coffee have a richer flavor. On the contrary, coffee that is not fully steamed will taste lighter and have higher acidity. In addition, you can also rotate the filter cup or poke a small hole in the middle of the coffee powder before adding water instead of stirring. The purpose is the same, which is to allow water to fully contact the coffee powder.

After steaming, you can continue to stir or swirl to ensure an even extraction. This reduces the possibility of channeling. It is important to pour water continuously to help extract the coffee more evenly. The first pour of water after steaming can be swirled or stirred to prevent the coffee grounds from sticking to the filter paper. During the extraction process, the volume of the wet coffee grounds increases as water is added. Therefore, the agitation can be greater. Stirring first in one direction and then in the opposite direction can help to remove large particles from the walls of the filter.

When large particles adhere to the wall of the filter cup, small particles gather in the center of the filter cup and sink. Small particles will be extracted to a greater extent, resulting in more bitterness. So try to ensure that each coffee particle can be properly extracted.

One test found that the length of the stirring time changed the total brew time. A 7-second swirl resulted in a total brew time of 5 minutes and 18 seconds, while a 2-second swirl resulted in a total brew time of 4 minutes and 28 seconds. This 50-second increase could be the difference between an even extraction and an over-extraction.

When stirring the coffee powder, the amount of water should be sufficient, especially when steaming. Some people think that 2:1 water-powder is enough, but in fact it cannot soak all the coffee powder. Experienced players recommend a ratio of more than 2:1 water to coffee, but higher than 3:1. Too much water may prevent the release of carbon dioxide.

When swirling or stirring the grounds, if there are signs of under-extraction, increase agitation, for example, by stirring once more or swirling for a second or two. Likewise, if the coffee is over-extracted, reduce stirring and swirling during the simmering phase and later in the brew.

In addition, the quality of the grinder is also a factor that may cause problems in extraction. The coffee powder ground by each brand of grinder will be different. Some beans (Ethiopia) are more likely to produce fine powder. It is recommended to grind medium first, and then adjust the grinding degree according to the performance.

A coarser grind size allows for more blending without worrying about over-extraction, as there are fewer fines and the particles are more uniform in size. However, if the grind is too coarse it can also result in under-extraction and a watery taste.

In general, whether it is rotation or stirring, it can bring a more ideal flavor to hand-brewed coffee. However, there is no one-size-fits-all method, and good taste is the only criterion for testing them. In actual operation, choose the one you are more accustomed to. It is important to ensure that there is a regular pattern for the rotation or stirring used each time, and then find the best solution by changing the stirring variables to extract your favorite flavor.

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