When exposed to air, coffee beans will oxidize. Coffee grounds suffer this more so because they have a larger surface than the beans and lack the beans’ protective skin. Home coffee grinders allow you to stop the level of exposure and produce the freshest grind. Most importantly, grinding can be done when you need it.
Everything has a price, though. Picking the best grinder can make the messy and long process of grinding much more rewarding.
There are three main types – blade, crusher and burr. The crusher is the ancient way of using a pestle and mortar to mash the beans. This process is difficult and gives an uneven grind because it just crushes them – not highly recommended. Blade grinders chop. The blade whirls, slicing the beans into small grounds – still not the best because the grains are not the same size and not all the oils are released, varying the flavour and dissipating a lot of the flavour. However, burrs use motorised plates with teeth that are pyramid in shape, allowing for the perfect grind. Better burrs allow for varied grain sizes because the speed can be adjusted accordingly.
The burr allows for the perfect brew. Speed control keeps the heating of the beans low.
Burrs have two categories. Professionals prefer the conical. It is noisy however. Good ones can go up to 500 rpm. Top quality ones go up to speeds of 10 thousand rpm, with their blades spinning at about twenty to thirty thousand rpm. This allows for fine grinds for Turkish coffee, for example. Some come with a dial for continuous speed adjustments. Others have buttons for some varied 40 different speed adjustments.
Beyond that you should look for ones that are solid in construction, easy to clean and preferably less noisy. They should also include a brush for cleaning and easy to remove upper type burrs (blades). Beware of construction materials that cause static electricity. This can let the grounds stick to the blades and the container.
Other useful features include a timer and an auto-switchoff. It also helps to be able watch the beans as the grinding takes place. Without this you cannot decide if the grind is ready. So, try to find one that doesn’t use glass or darkish plastic as this hinders your view. You should be able to judge the grind by its colour, but if you cannot see them then this is a problem.
Finally, do your research and read all the reviews you can find about each grinder that interests you before you buy it. When you find the right one, you will be pleased with the fresh and flavoursome cup of coffee you produce.