Think of an Italian café. The waiter brings you a small, white, porcelain cup stained by a rich espresso crema. You sip it and – smack – it hits you, right on the roof of your mouth.
Bitterness. It overrides the subtleties of the shot and leaves an aftertaste not worth remembering. Yet bitterness is an often desirable aspect of the drink.
Did you know that there are two different types of coffee beans? Arabica, which is generally smooth and clean, and Robusta, which can have a more bitter mouthfeel. Robusta is often added to espresso blends to help form a nice crema, or frothy head, to the espresso. It also lends its potent bitterness, which helps many espressos to stand out through milk.
However, when an espresso tastes overly bitter this is most likely due to poor preparation, and may not be because of the Robusta beans. In a properly made espresso, the hot water is forced through finely ground coffee, pushing fatty lipids (oils) into the drink, which, in turn, coat your tongue, protecting it against bitter flavors. If the oils were not extracted adequately, and the tongue is not coated, then the full bitterness may come through.
If you are having problems making a smooth espresso, try adjusting your grind and make sure that you are packing the coffee down firmly and evenly, but not too tight. Of course, make sure you’re using freshly roasted coffee as well. If you’re still having problems, write us at firstname.lastname@example.org and we’ll help diagnose your problem!