Acidity in coffee: What it is and why it matters

At Unity Coffee Roasters, we often hear one common question:
“Why is coffee acidic?”

The answer is actually quite simple.

Coffee is a fruit.
And like all fruits, it naturally contains acids — the same compounds that make berries taste fresh, juicy, and vibrant. Think of a raspberry, a green apple, or a citrus fruit. Acidity is what brings life and clarity to those flavors, and coffee is no different.

What determines acidity in coffee?

Coffee acidity is shaped by three main factors:

1. Origin: place of growth

Where coffee grows has a huge impact on how it tastes.

Climate, soil, and local conditions all influence how acids develop in the coffee cherry. As a general rule:

• Coffees from Africa are well known for their bright, juicy, and crisp acidity.

• Coffees from Central and South America often show balanced, medium acidity.

• Coffees from Asia tend to be calmer, rounder, and lower in perceived acidity.

Each origin expresses acidity differently — from citrus and berries to softer, wine-like notes.

2. Altitude

Altitude plays a key role in acidity development.

The higher a coffee grows, the slower the cherries ripen. This longer ripening time allows the plant to develop more complex organic acids, resulting in a brighter, more layered cup. High-altitude coffees often taste more vibrant and refined, with greater clarity.

3. Processing Method

Processing refers to how the coffee cherry is handled after harvest, and it directly affects acidity.

There are no absolute rules, but most coffees fall into two broad categories:

• Washed (wet-processed) coffees
  These are typically cleaner, more transparent, and higher in perceived acidity.

• Fermented or natural coffees
  Here, acidity is partly created through fermentation, where bacteria interact with sugars in the fruit. This often leads to richer, funkier, or more wine-like acidity.

If you’re looking for an acidic coffee, processing is one of the first things to pay attention to.

Acidity is not a bad thing!

If coffee acidity still sounds intimidating, here’s the most important thing to remember:

Acidity is a fundamental part of balance in the cup.

It doesn’t have to be intense or sharp. Even in small amounts, acidity makes coffee more complex, layered, and alive. Without it, coffee can taste flat, dull, or heavy.

What truly matters is proper roasting.

If coffee is underdeveloped, acidity can taste harsh, sour, and unripe.
If it’s roasted too dark, acidity can disappear entirely, leaving the cup heavy and one-dimensional.

Fruit is the perfect analogy:

• An unripe apple tastes sour and astringent.

• An overripe apple can be cloyingly sweet or unpleasant.

• But a perfectly ripe apple is always enjoyable ✨

The same is true for coffee.

And if you’re already a fan of bright, expressive coffees, our video includes a simple guide on how to choose the acidity profile that best suits your taste.

Acidity isn’t something to fear — it’s something to understand, appreciate, and enjoy.