Acidity — often mistaken for acrid, bitter or pungent — is at the heart of the flavor chain.
In truth, acidity is the dry, bright and sparkling sensation that sets a high-quality coffee from a mundane, flat cup. The comparison to a nice wine or a craft-beer experience is what comes to mind with a better cup.
Acidity is not a flaw. It is a feature. Here is how to spot them: Citric Acid: Think lemons, oranges, and bright berries. Malic Acid: Crisp and smooth, like a green apple. Phosphoric Acid: Sparkly and sweet, cola-like mouthfeel. Once you start tasting these, you will never look at black coffee the same way again.
Highly prized coffees are characterized by bright, nuanced qualities; quite often, they are unforgettable. A standard cup of coffee will have no movement or effervescence — your takeaway, "It's just coffee." Well-curated, fresh-roasted brew will show up with bubbles or brownish crema during brewing or after poured. This is a sign of the flavors active as a result of the acids contained in the coffee. Most of the flavors that Q-graders taste and list when scoring coffee are found when the cup reaches 160-150 degrees. This is the best point to begin enjoying your brew.
Acidity and complexity go hand in hand in single-origin specialty coffee. Even savory flavors like nuts and malt are part of the wheel of flavors.
The SCA Flavor Wheel is a vocabulary reference organized by flavor category. It begins with 9 general flavor groupings in the center and begins an ascent to the perimeter where 110 descriptors can be detected.