The daily grind: a few words about grinding coffee

Blades or burrs?

Ask most coffee connoisseurs to choose between a blade grinder and its burr-equipped rival and they will choose the latter. A burr grinder, with two surfaces that grind the coffee, has more advantages, though manual models take a little longer. What does a burr grinder, often also called a ceramic grinder, do better than one equipped with “sabres”? Above all, it grinds evenly, maintaining a consistent particle size. More importantly, each piece passes through once and falls into the lower container to await its fate. That is a major advantage over blade grinders, which treat coffee harshly, sometimes chopping the same bean dozens or hundreds of times.

As you might guess, consistency affects the finished cup. Randomly chopped pieces release their flavours just as randomly during brewing, which is not good news for the coffee.

Big and small — coffee grind sizes

Now that we know which grinder suits our dreams of evenly ground coffee, we have to choose the grind size. Fortunately, almost every grinder today, even a blade model, offers some control over fineness. Trust those of us who heard complaints early in our barista careers about particles floating in a freshly brewed cup: grind size really matters. Why?

If you dream of an intense espresso as dark as a fallen angel's soul but grind too coarsely, water rushes through the loosely packed grounds before extracting all their flavours. Conversely, use too fine a grind for a light, angelic Chemex and the water cannot squeeze between particles fitted together like a jigsaw. The result is an unpleasant, over-extracted brew.

How should you grind coffee?

There are three basic grind sizes:

• Fine
• Medium
• Coarse

It helps to recognise them without measuring particles. Fine coffee should resemble sugar crystals, medium coffee sand and coarse coffee table salt. This knowledge may come in handy at your aunt's name-day celebration when you have a packet of ground coffee and need to decide whether it is better suited to a dripper or moka pot. Because...

Grinding and brewing method

...the brewing method depends on the grind. As with everything in coffee, how we do things matters most. Particle size has a major influence on flavour extraction.

Put simply, grind fineness should be inversely related to brewing time. That is all, and quite a lot. For slower pour-over methods, where water is added in small portions, grind fairly coarsely. For concentrated espresso, exposed briefly to high-pressure water, use a very fine grind.

Why? Particle size affects how long water takes to pass through the coffee, influencing the gradual release of flavours and aromas. Give them the time they need and they will develop beautifully, revealing all the mandarin, citrus and caramel notes you hoped for when buying freshly roasted beans from your favourite barista.