Grinding your own coffee is one of the best steps you can take towards a superior brew. Coffee stales quickly after it is ground; buying fresh coffee from a local roaster and having them grind it in the store largely negates the benefits of purchasing recently roasted coffee.
The most commonly found grinders look like miniature blenders, and they operate by chopping up the beans with two or more sharp blades spinning at high speeds. Less common are burr grinders: the beans are placed in a hopper on top of the machine, and they feed between two metal rings (burrs) and down into a bin. One of the burrs is fixed in place and the other rotates a small distance away from it; the beans are fed into a hole in the center of the top burr and are sliced down by the burr teeth as they make their way between the two burrs to the outside, where they are ejected. Manually operated versions can be purchased, as well as the electric models. The hand-cranked models are related to flour mills, but home flour mills will not usually grind coffee well and may become clogged by the coffee oils.
4.2.1 Burr grinders versus blade grinders
Blade grinders (also called “whirly blade” grinders) are not able to produce a consistent particle size: the size of the grounds in any particular batch will be quite varied. As a result, coffee extraction will be uneven, with the larger particles underextracting (producing thin, weak coffee), and the smaller particles overextracting (producing bitter coffee); this does not “even out.” This problem is undesirable for brewed coffee and a fatal flaw when making espresso. Part of the problem is that the user cannot control exactly what is being ground: one bean or bean piece may be chopped into smaller and smaller pieces, while another somewhat escapes the blades. This issue may be somewhat addressed by gently shaking the grinder while it is operating. Although certainly better than using stale coffee, blade grinders are best used for spices, though they may also work acceptably for producing the talcum-powder fine grind necessary for Turkish coffee.
4.2.2 Flat Plate Burr Grinders vs. Conical Burr Grinders
There are two kinds of burr grinder:
1) flat-plate, shaped like two stacked dinner plates
2) conical, like two glasses stacked one inside the other.
For either type, each facing surfaces bears cutting teeth. As compared to a flat surface, a conical surface will have a greater grinding surface for a given diameter; imagine the cutting surface of a conical grinder being the hypotenuse of a right triangle, angling downwards, while the cutting surface of a flat grinder is the horizontal axis of the same triangle. The greater the angle away from the horizontal, the longer the hypotenuse (the conical burr) as compared to the side at zero degrees horizontal (the flat burr), even though the hypotenuse takes up the same horizontal distance. As a result, the conical grinders require a lower rotational speed, since the beans will feed through a longer distance with more burr contact.
That said, no conclusive results have come out of the arguments comparing the two types. However, some conclusions can be made. As always, price tends to go hand in hand with quality. The cheapest burr grinders—less than $50—are often little better than blade grinders. Their burrs are of lesser quality, and are often mounted in plastic carriers that do not hold the burrs rigidly, decreasing grind quality and burr life. The design and quality deficiencies of these inexpensive burr grinders do not justify their cost.
When researching brands, also look into how noisy each model is; some are surprisingly quiet, some sound like outdoor gardening tools. Some machines are prone to static problems, which can cause the grounds to fly all over the place, especially when humidity levels are low. Some machines have relatively long chutes between the burr chamber and the grounds bin; these long chutes may be prone to clogging. Some machines come with dosing chambers, which are meant to make it easier to fill an espresso machine portafilter. Some people like these chambers, others hate them, but they are of little use if you are not grinding for an espresso machine.
Some grinders use a worm gear to change grind fineness, for others, you rotate the top of the machine (usually, the bean hopper), effectively screwing the burrs closer together or further away. The worm gear is usually far more adjustable, but it is more difficult to repeatedly change back and forth between specific settings.
4.2.3 Manual Grinders
These are essentially burr grinders without the electric motors. Some of the better quality manual grinders (many people favor the Zassenhaus) produce excellent quality grinds. The downside is effort; it takes a significant amount of grinding to produce enough for a pot of coffee. The grinding time required to produce a particular quantity increases with the fineness of the grind, and the effort needed can be exasperating for espresso drinkers.
4.3 Cleaning coffee makers
Carafes should be well-rinsed after each brewing session. This includes autodrip, French press, thermal, or any other such devices that can be safely submerged and are used to hold brewed coffee—that is, you want to wash away the remains of the brew. Be mindful if you use an autodrip machine’s warming plate, as it will often bake coffee residue onto the carafe bottom; the warming plate itself should be wiped off, when cool, with a slightly damp but not wet paper towel.Certain carafes contain integrated heating devices (e.g., the Bodum electric Santos vac pots and the ChefsChoice electric French press). These should have their insides well rinsed, but cannot be submerged.
Complete cleaning of coffee equipment requires separate acid and alkaline solutions. Acids (vinegar, citric acid) are necessary for cleaning mineral deposits, while a base (baking soda, most detergents) helps clean the weakly acidic coffee deposits.
Common sense dictates that you not immerse electrical equipment. As touched upon above, “cordless” electric carafes only contain part of their circuity inside their base. The rest is in the bottom of the water chamber, which therefore cannot be immersed, nor should its outside be allowed to get wet.
sursa: http://www.thecoffeefaq.com
