Which coffee beans for espresso?

For an espresso, the roast matters most. Origin can give subtle differences in taste, but you recognise an espresso mainly by its strong flavour. That comes mostly from the roast: espresso beans are usually roasted longer, which makes them darker and gives a somewhat more bitter, chocolatey taste. When beans are roasted lighter, the acidity and fruity flavours come forward more. Everyone has their own taste, but most people will recognise the bitter taste as espresso.

So when a bag says “espresso beans” or “espresso roast”, that says nothing about the origin. It only means the beans were roasted longer (and so darker). It is not a variety of bean and not a quality mark.

Many people first look at the best-before date when they buy coffee beans at the supermarket. That is often a year or more away. It does not mean the beans make good coffee for that whole period, or that their taste does not change.

The roast date matters far more. Freshly roasted beans usually taste best between 7 and 28 days after the roast date. No roast date on the bag? Then I would leave them on the shelf. In the first 7 days after roasting the beans are still degassing strongly, and after 28 days the aroma starts to fade. While degassing, the CO2 created during roasting leaves the beans. Less CO2 means the water can draw the flavours out of the coffee better, so you get the most out of it. So do not buy big bags if you will not finish them within three weeks; choose smaller bags and buy them more often.

Most specialty coffees are 100% arabica. Robusta used to be known mainly as a cheap filler, but high-quality robusta can add something. A small amount often gives more body and a fuller, firmer layer of crema. That is why robusta is widely used in traditional Italian espresso blends.

For a classic Italian espresso, a blend with 10 to 20% robusta is a good choice. If you prefer fruity, fresh and refined flavours, 100% arabica will probably suit you better.

In principle both kinds of machine can handle espresso beans, but for a bean-to-cup a slightly lighter roast is wiser. Why? Dark roasted beans release more oil when ground, which can make the grinder dirty and clog it. With a manual espresso machine that is usually not a problem, because you can clean the grinder more thoroughly and easily. With a bean-to-cup you often cannot, which is why bean-to-cup makers often advise against dark, oily beans.

Air, light, heat and moisture all affect the taste of coffee beans. Keep your beans in a closed canister (airtight, lightproof and moisture-proof) at room temperature. Storing them in the fridge is not a good idea: the temperature difference makes condensation form on the beans when you take them out.

You can freeze your beans in small airtight portions and thaw them, but buying and using smaller amounts of coffee beans is a lot simpler.