Fine coffee beans knowledge coffee bean grinding roughness and fineness

Freshness is the first requirement of good coffee, and the second priority is to master the grinding thickness of coffee beans, which directly affects the extraction effect, that is, the quality and intensity of coffee flavor. In principle, the finer the coffee powder, the longer the brewing time, the stronger the coffee taste; conversely, the coarser the coffee powder, the shorter the brewing time, the lighter the taste. The longer the extraction time, the coarser the beans should be ground to avoid excessive extraction and bitterness; the shorter the extraction time, the finer the beans should be ground to avoid insufficient extraction.

For example, the extraction time of French press is about three to four minutes, it is suitable to use coarse grinding, household hand-press grinder (commonly known as bean chopper or known as propeller grinder) can be released by pressing for seven to ten seconds, if the grinding is too fine, easy to drink coffee grounds and have a bitter taste. Filter paper or plug air brewing method, because the extraction time is relatively short, about one or two minutes, coffee beans should be ground a little finer than the French filter pot, about ten to fifteen seconds, but it is best to use a grinder to grind.

Mocha pot is more complex, and the use of heating energy, if it is a gas stove, the heat is fierce, it is best to grind a bit coarse, so as not to extract too much. It is recommended to use an induction cooker or alcohol lamp, the fire is better controlled, otherwise the mocha pot is easy to bubble bitter and strong and bite the throat of choking coffee. Mocha pot extraction time is shorter than French filter pot, filter paper or plug air, so coffee powder should be slightly finer, grinding time is about 15 seconds to 20 seconds, if the fire source is larger can be ground a little coarse, fire source is smaller ground a little, elastic space is quite large. To sum up the above key points, all kinds of soaking methods are different due to the length of extraction time, and the required thickness of coffee powder is also different. In principle, the shorter the extraction time, the finer the particles, the longer the extraction time, and the coarser the particles.

Espresso served in a two-gear grinder

French press, corkscrew, drip, or mocha pots do not require a high degree of fineness in coffee powder. The knife pulp grinder (commonly known as the bean cutter or the propeller grinder) cannot adjust the scale, and the thickness is adjusted according to the length of time. The particle size of the coffee powder is uneven, which is not suitable for espresso. The popular belief that an espresso machine is all it takes to make a good espresso is only half true. The other half is done by a more sophisticated two-gear grinder. The lower gear of this grinder is connected to a powerful motor to provide high-speed rotation force, while the upper gear is connected to the scale and twisted counterclockwise. The reading of the scale is getting smaller and smaller, and the upper gear is also decreasing. The distance between the lower gear and the ground coffee powder is getting finer. If the upper gear is twisted clockwise, the larger the scale value, the upper gear rises upward, widening the distance between the upper gear and the lower gear, so the coffee powder ground is coarser.

Double-gear grinder is to adjust the height of each other to set the coffee powder thickness, do not underestimate this grinder, its structure is extremely precise, less double-gear grinder, it is impossible to brew thick, authentic espresso.

Check the quality of espresso.

Espresso success depends on flow rate, color or seconds counted, only 51 percent accuracy, you have to try it yourself to be safe. Although the visual method is not very accurate, there is a visual gauge below to provide reference:

Feature underextraction perfect extraction overextraction

Extraction time 4-19 seconds 20-25 seconds 26-45 seconds

The fluid pattern is coarser, water-jet-like, viscous, and broken into droplets.

Crema color pale to yellowish golden to reddish brown to charred

crema thickness

Very thin, up to 1/3 thick, very thin to nothing.

Crima firmness fragile fit high fragile

Poor aroma and flavor, intense, complex, sour, bitter