Coffee beans, like any food product, oxidize when exposed to air. The grounds, since they have a much larger
relative surface area than the bean, and no covering, suffer this effect even more. Grinding beans at home
produces the least exposure to air and the freshest
grounds. And you can grind only what you immediately
But nothing is without its price. Grinding is time
consuming and messy, so if you choose to invest the
effort to reap the reward, pick the best you can afford.
Grinders fall into three broad categories - burr, blade and
The third type is some kind of mashing device, often an
ancient-style mortar and pestle. These crush the beans, which is difficult and produces a very uneven sized
granule. Not recommended where you have a choice.
The blade grinders don't actually grind at all, they chop. A whirling blade slices the beans into smaller and
smaller sections until they approach something like a small grain. Unfortunately, the grains are invariably too
large and of inconsistent size.
As a consequence the surface areas of the granules vary, releasing varying amounts of flavor oils when
brewed. Another effect of slicing is often the production of excess heat, as a result of the high speed of the
blades. That friction warms the grounds and partially dissipates the aroma.
The first type is the first choice. Burr grinders have a pair of motor driven plates with pyramid-shaped teeth
that grind the beans to a consistent, small-but-not-too-small granule. The better models allow adjusting the size
of the grain and the speed of the grinding.
Adjusting the size is important in order to 'fine tune' the grounds to allow just the desired brew. Controlling the
speed keeps the warming effect to a minimum.
Even burr grinders fall into two classes - the conical burr grinder is preferred by real coffee aficionados.
Though noisier, they allow the most control of grain size and speed.
Good conical burr grinders can rotate as slowly as 500rpm. By contrast other burr grinders spin at 10,000rpm
or higher, blades between 20-30,000rpm. That allows very fine control and little heat. The fine grind is
especially important for Turkish-style brews. Some grinders have a continuous dial, others have a series of up
to 40 steps to adjust the granule size.
Beyond those broad attributes, the home barista will want to look for solid construction, ease of cleaning and
low noise. A cleaning brush and removable upper burrs is essential. Different materials used can also affect
how much static electricity is produced - that causes the grains to stick to the burrs and container.
A timer switch and auto-shutoff is a nice addition and being able to see the beans as well as the grounds is
helpful for judging the results in the grinder. Dark plastic or glass may be aesthetically appealing but it
obscures the view. Grounds can change color slightly depending on the fineness.
Read reviews and be prepared to spend a little more and you'll be rewarded with the freshest, most flavorful