How to prepare coffee for brewing

What is the best coffee for an espresso machine? How should it be prepared, roasted and ground? Why does grind size matter so much, and how does it help reveal the best in the beans? Here are some practical pointers for preparing coffee to brew.

Several things need to come together to bring out a coffee's character. First, choose freshly roasted beans. This guide recommends using them within about a month of roasting, with particular attention to the first two weeks; the best resting and drinking window will vary with the roast and brewing method.

Second, the roast should suit the characteristics of the variety or blend. Third, the grind size needs to match the coffee, roast level and, above all, the way you plan to brew it.

Grinding — a key to success

Grinding may look simple, but it is one of the most important steps in determining the flavour of your cup. Espresso is especially demanding: hot water passes through the grounds under pressure, so small differences in preparation can have a large effect.

Careful preparation brings out distinctive aromas and flavour notes. A good grinder is essential. If your machine has an integrated grinder, adjust it for the coffee you are using. Adjustable burr grinders are particularly useful.

Consistency matters as much as the chosen setting. When the particles differ greatly in size, the smaller ones can over-extract while larger ones remain under-extracted, creating an unbalanced flavour. Avoid overheating the beans during grinding, following your grinder's instructions and taking short breaks if needed.

A short guide to grind sizes

• Coarse: particles resemble coarse sea-salt crystals. This is a useful starting point for a French press and some percolator recipes. Longer contact with water gives the larger particles time to extract, while the brewer's filter separates the grounds.
• Medium: a sand-like texture. Medium settings are commonly used for filter brewing; a moka pot often benefits from a somewhat finer, medium-fine setting. Aim for good extraction without fine particles passing into the drink or obstructing the filter.
• Fine: a texture approaching fine sugar is typical for espresso. An even finer, flour-like powder is used for Turkish coffee. These are different settings, despite both falling at the fine end of the range.

Remember that the brewing method is not the only consideration. Roast level and the time since roasting can also affect the setting you need. Light roasts often require a finer grind than darker ones for a comparable recipe. As beans age, you may need to adjust the grinder again. Let the flavour guide those final changes.