The Difference Between Sour & Bitter Coffee

The Difference Between Sour & Bitter Coffee

First of All – What is Sour Coffee?

Sour, or acidic coffee is the flavor profile of coffee beans that have not been fully extracted.

What causes sour coffee?

  • Too much water/not enough coffee imbalance
  • The water was not hot enough or was too hot
  • The coffee was not brewed long enough
  • The grind may be too coarse

If you are brewing with a single cup coffee machine you may find the sour or fruity acidic notes come to the forefront of the cup. This is a result of the brewing method, where the coffee is not brewed for long enough to allow the flavor profiles to fully develop.

Temperature has a significantly greater affect on sour notes over bitter notes. If your coffee is sour, you may want to increase your brewing temperature.

So What is Bitter Coffee Then?

Bitter coffee is a flavor profile that can develop very quickly when the beans are over-extracted.

What causes bitter coffee?

  • Not enough water/too much coffee imbalance
  • The water was too hot
  • The coffee was brewed too long
  • The grind may be too fine

You can avoid the bitterness overtaking your coffee by ensuring you pour the cup as it is ready.

Which Types of Coffee are Naturally Bitter?

The higher the altitude where a coffee is grown, the higher in caffeine it will generally be. Caffeine provides a bitter flavor, so as caffeine level increases so does the bitterness of a coffee bean ( usually).

Robusta Beans Are More Bitter

Robusta beans will typically have a darker roast and a higher caffeine level compared to Arabica beans. They can be incredibly bitter, especially when lower in quality.

Due to the bitter flavor of this bean, it is used almost exclusively in instant coffee, espresso blends, and as filler in cheaper pre-ground blends.

Dark Roasts Have Less Acidity and More Bitter Overtones

The darker a coffee is roasted, the more bitter flavors are released. As the roast gets darker, so does the level of bitterness to the final brew.

If you’re not a fan of a bitter cup, you should steer clear of darker roasts and try a light roast instead.

While a light roast does have a higher caffeine content, the bitter flavor of a dark roast is far more overpowering than that of the caffeine in a light roast. Coffee beans used to make dark roasts and espressos are usually Robusta, which has far more caffeine than the Arabica variety.

Instead of a French Roast, try an American or City Roast and you may find a more mellow flavor with less bitter punch.

Arabica Beans Don’t Tend to be Naturally Bitter Unless Over-extracted

Arabica beans are the best choice for least bitterness. Compared to the Robusta bean, they are half as caffeinated and typically used to make lighter roasts in the light to medium range.

You should only purchase Arabica beans for a standard daily coffee from a reputable source. You should always buy your coffee beans fresh and grind them freshly at home for each use.

You can tell the difference between Arabica and Robusta beans by the shape, where Arabica beans are the more typical shape you might think of, long and oval, Robusta beans are more the shape of a pea. This is an easy check to make sure you’re getting the quality of coffee bean you expect from your provider.

If you find that your typical is a blend, which can be very common to almost every bag purchased on a store shelf, you will enjoy the reduction in bitterness that comes from a truly 100% Arabica coffee variety.

Ways to experiment for the best cuppa joe:

  • Brew time
  • Grind size
  • Brew temperature

How Brew Time Adjustments Can Alter The Flavor

First you should try experimenting with your brew times. Start with brewing your cup for just 1 or 2 minutes, then try 3 or 4 minutes. Next you could try 6 to 8 minutes. What do you notice is different between the cups of coffee?

At two minutes, more of the acidic, fruity and sour notes have developed. The sweet and bitter notes haven’t yet had a chance to fully develop. While the fruity acids that come out to play after 2 minutes may please some palettes, most will want to brew a touch longer to allow the flavor profiles to fully develop.

At three to four minutes, you will find that your cuppa has started to develop some darker flavors, the bitterness of dark chocolate may start to come through along with some sweeter flavors.

If you experimented with eight minutes, you would find a very bold, dark flavor profile that you may not have expected from your coffee. The bitterness will truly have time to take hold and is likely to overpower any other flavor profile the coffee may have had to offer. If you like a deep flavored, bitter coffee, this may be the method for you.

How Grind Size Affects Your Cup of Coffee

Another experiment to try is varying the size of your coffee grind. A finer grind will allow flavor profiles to develop more quickly, so you will find a finer grind requires a shorter brew time. However, with filter brewing you will also find that a finer grind means a longer brewing time.

It can be tricky to find the right grind, but you will be glad when you do. It is preferable to grind your fresh beans using a burr grinder over a blade grinder as it allows more control of the grind, as well as providing a more consistent final product.

Brew Temperature Can Make Coffee Sour or Bitter Too!

The final method to experiment with is your brewing temperature. This may require some kitchen gadgets that you don’t already have, like a variable temperature kettle, or for the coffee and tea aficionado a hot water dispenser may be a time saving investment. Most offer at least three temperature settings, 150F, 185F and 205F. Some give you even greater control.

Start at the lowest temperature and work your way up. You’ll find that at lower temperatures, sour and sweet notes are more developed, while bitter notes aren’t as punchy. At higher temperatures, all the flavors may come through more boldly.

Most of all, the coffee brewing process is a personal preference. Happy sipping!

Brian Mounts

Head blogger, editor, and owner of "Top Off My Coffee", a website that has been educating readers about coffee brewing techniques and equipment since 2012.

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