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If you are thinking about buying a coffee grinder, here's what you need to consider.

Why grind?

Well, the flavours in espresso are created by roasting coffee beans and grinding them to expose the coffee's oils. The oils begin to evaporate soon after grinding, so for the freshest espresso you need to grind whole beans just before you use them.

The coarseness of your grind influences the strength of your espresso. A good grinder allows you to experiment with different grind textures until you find one that's right for you. Some grinders have 50 settings.

Choosing the right grinder

Burr grinders are the grinder of choice because they produce more uniform grounds than blade grinders. All the models we tested were burr grinders, but not all of them were created equal (see the Test results).

Burr vs blade

• A burr grinder works by crushing the beans between outer and inner cones. The cones are made of a hard material and are ribbed to grip the beans. The inner cone rotates, while the outer cone is stationary. Grind fineness is set by adjusting the distance between the cones. 
• A blade grinder (pictured above right) works like a blender: A high-speed rotating blade chops up the beans. The fineness of the grind depends on how long the grinder runs … and you have to judge how long. Run it too long and you’ll get such a fine grind that it can block up the filter basket and maybe damage the espresso machine’s pump. Blade grinders produce a less even grind than burr grinders.

Grinding tips

• Using the right type of grind and looking after your beans and grinder means better coffee. Coarse grinds suit percolators, medium is for plungers, fine is for filter and espresso, extra fine is best for Turkish coffee.
• Make your grinds finer and tamp them more firmly if your espresso’s too weak. Coarsen the grinds if it’s too bitter.
• Dosers allow you to fill your grind basket with a certain amount of ground coffee by pulling a lever – like they do in a café.
• Most machines allow you to grind directly into your filter basket.
• Only grind as much coffee as you need at one time. Coffee loses freshness very quickly – some baristas will discard coffee they ground just half-an-hour before.
• Clean your hopper and grinds container regularly. The oil from the beans goes rancid if left too long.
• Store beans in an airtight container out of direct light.