 coffee grinder
Coffee is often processed with a coffee grinder before we can turn it in to that much sought after beverage called coffee. The fineness of the grounds has a major impact on the brewing process, and matching the consistency of the grind with the brewing method is critical to extracting the optimal amount of flavour from the roasted beans. Brewing methods which expose coffee grounds to heated water for a longer duration require a coarser grind than faster brewing methods. Beans which are too finely ground for the brewing method in which they are used will expose too much surface area to the heated water and produce a bitter, harsh, "over-extracted" taste. At the other extreme, an overly coarse grind will produce a weak, watery, under-flavoured result.
coffee grinder
With the rise of coffee as a fashionable beverage, it has become much more popular to grind the beans at home before brewing, and there are many home appliances available which are dedicated to the process. There are three methods of producing coffee grounds ready for brewing.
Burr-grinding. This method is burr-based with two revolving elements crushing or "tearing" the bean and with less risk of burning. Burr coffee grinders can be either wheel or conical; the latter are quieter and are less likely to clog. A burr coffee grinder will "mill" the coffee to a reasonably consistent size, which produces a more even extraction when brewed.
A conical burr coffee grinder preserves the most aroma and produce very fine and consistent grounds. The intricate design of the steel burrs allows a high gear reduction to slow down the grinding speed. The slower the speed, the less heat is imparted to the ground coffee, thus preserving maximum amount of aroma. Because of the wide range of grind settings, these grinders are ideal for all kinds of coffee equipment: espresso, drip, percolators, French press. Better conical burr grinders can also grind extra fine for the preparation of Turkish coffee. Grinding speed is generally below 500 rpm.
Burr coffee grinders with disk-type burrs usually grind at a faster speed than conical burr grinders and as a result tend to create a bit more warmth in the coffee. They are the most economical way of getting a consistent grind in a wide range of applications. They are well suited for most home coffee preparation.
Chopping. Many modern coffee grinders chop the bean into pieces (and some coffee drinkers merely use a home blender to do the job). Although enjoying a much longer life before wearing out the blades, the result will create inconsistent extraction and a degraded product in the cup.
A blade coffee grinder will smash the beans with a blade at very high speed (20,000 to 30,000 rpm). The ground coffee has larger and smaller particles and is warmer than ground coffee from a burr coffee grinder. A blade coffee grinder will create “coffee dust” which can clog up sieves in espresso machines and French presses. But they can still produce great coffee. |
