Why is my coffee sour?

This is the question we get asked most often across the counter. And almost always the answer is the same: the coffee is not sour, it is unfinished.

First, two different things

Acidity and sourness are not the same.

Acidity is a good thing. It reminds you of apple, lemon or strawberry, it makes a cup feel alive, and it is a sign of a well made light roast.

Sourness is sharp, flat and unpleasant: like unripe fruit, it grips the sides of your tongue and leaves nothing behind it.

The first is the goal. The second is a problem.

Why it happens

Flavours come out of coffee in an order: acids first, then sweetness, bitterness last. If the water has not worked on the grounds for long enough, you get only the first part - acids with no sweetness behind them. That is under-extraction.

So sour coffee usually means the water pulled too little out of the beans.

What to change, in order

• Grind finer. This has the biggest effect, so try it first.
• Use hotter water: 92-94 °C. Let boiled water stand for a minute and that is close enough.
• Check your ratio. For filter, around 1:16 - 15 g of coffee to 250 g of water.
• Pour more slowly, so the water spends longer in contact with the coffee.

Change one thing at a time. Change two and you will never know which one worked.

Sometimes it is not you

A light-roasted natural Ethiopian is never going to be chocolatey and soft - that is simply not what it is. If you do not enjoy fruit and floral notes, the problem is not your brewing; you want a different coffee.

If you cannot tell which it is, bring it into one of our coffee shops. We will brew it beside something else and hear the difference together.