Adjusting the grinding settings is not something mystery among experienced baristas. With many people owning coffee machines and grinders at home, understanding how to adjust the grinders correctly have become an essential skill to produce a great cup of coffee.
Why Adjust Grinding Settings
We need to brew coffee with certain amount of time to ensure the coffee crema and oil is correctly extracted. To achieve this, the coffee beans need to be grinded into particles. In a typical Italian Espresso, the coffee beans are grinded into small particles and then pressed together for coffee extraction. The smaller the particle is, the longer the extraction time. In other words, how fine or coarse the coffee particle would directly determine how long the coffee espresso is extracted and then affect the coffee taste. This is very similar to the sand vs stone. The water would drip through stone with no obstacles, whereas it takes a lot longer to pass through sand.
The Flavor Differences With Different Grinding Settings
We now know that the coffee particle size would affect the coffee extraction and taste, and what is the correlation between them?
A short answer is, the longer the extraction time, the bitter the coffee is. The shorter the extraction time, the sour the coffee is. Over extraction or under extraction are not something we are after, and we need to fine-tune the grinding settings to achieve the sweet point.
Another interesting fact is that the coffee grinding setting would also affect how much coffee dose is produced. A straight away correlation is that the finer the grinding setting, the less the coffee dose is generated in the same time period, and vise versa. But why is that?
When the coffee grinder is set to a finer side, the blade would require more time to grind the coffee beans finer, and as a result, it would produce less coffee doses.
Change Grinding Settings Safely
It is highly recommended to change the grinding settings when the machine is off and not operating. This is because when the grinding settings are changed, the position between blades would also alter. If the machine is still on and operating, such change would damage the blades and it would die off quicker than expected.
When a coffee grinder has been operating continuously for a while, the temperature would rise. This would cause blades are tightened than the normal status, thus cause the coffee particle to be too fine. In that case, we need to adjust the grinding settings to coarse and offset that impact.
Brewing Guide for Espresso Coffee
When you are using coffee blends like Breeze Aroma, Hurricane Berry or Zephyr Plum, or any of the single origin espresso coffee for extracting espresso, we recommend the dial the grinding settings to the finer side. This is because when extracting espresso, coffee machine usually generates as high as 15 Bar of pressure, a finer setting would help to slow down the extraction process and increase the brewing time.
Brewing Guide for Filter Coffee
If you are using filter coffee for AeroPress, Cuppamoka, we recommend to dial the grinding setting to the coarse side. Filter coffee usually does not require a high pressure for extraction, and the timing is usually much longer compared to espresso. A coarser setting could help to offset the long extraction time.
The Bottom Line
Changing the grinding setting is not mystery, and many factors will affect how you would change it to finer or coarser side. The best practice is always to have a taste of the coffee. If it tastes bitter, we tend to change it to coarser side, reduce dose amount, and shorten the extraction timing. If tastes sour, change it to the other side instead.