Which coffee beans should you buy?

You've invested in a machine costing €500 or more. Now, the coffee you put in it will account for 80% of the result in the cup. Here's how to choose.

Roast: light, medium or dark?

• Light roast (blonde) : more acidic, fruitier, more caffeine. Ideal for filter and specialty coffees.
• Medium roast : balanced, caramel notes. The best choice for daily espresso.
• Dark roast : full-bodied, bitter, less acidic. Typical of Italian blends. Watch out for overly oily beans.

Arabica vs Robusta

Arabica (80% of world production) gives a sweeter, more aromatic coffee with less caffeine. Robusta is fuller-bodied, more bitter, with 2× more caffeine. For espresso, an 80% arabica / 20% robusta blend gives a nice crema and body without attacking the palate.

Freshness: the criterion that changes everything

Bean coffee keeps for 3-4 weeks after roasting. Beyond that, it loses its aromas. Buy packs of 250g or 500g maximum, with a roast date (not just a best-before date). The big brands (Lavazza, Segafredo, Illy) are nitrogen-flushed and keep better.

Price per kilo

• Entry level (supermarket) : €8-15/kg — fine for everyday
• Mid-range (Lavazza, Illy) : €15-25/kg — good value for money
• Specialty (local roasters) : €25-50/kg — for enthusiasts