Coffee acidity – is it good or bad for you?

Coffee acidity is riding that third wave tall and proud. Baristas love it, small roasteries adore it, and the cupping judges are making it one of the key cupping factors. But have you ever wondered what that term means? Why would someone like acidic coffee? 

Let’s find out.

Coffee acidity and its role in the coffee universe

When people hear the word acid, their brain starts picturing things. Mainly in the range from battery acid to the birth of the supervillains. However, coffee acidity can have many meanings.

Coffee acidity on a pH scale

Science time. PH scale is a measure for acidity. The scale goes from 0 to 14. The solutions ranging from 0 to 7 are acidic, while 7 – 14 are basic.

Coffee is an acidic liquid, ranging around 5 on that scale. This is just for observing coffee as a liquid. In the matter of flavour, the coffee’s pH level plays no role. As you can see, orange juice, beer or wine are much more acidic than coffee.

Here are nine main acids that coffee contains, along with their positive impacts on health:

  • Chlorogenic acid – lowers blood sugar level
  • Quinic acid – emphasizes the antioxidant effects
  • Citric acid – the antibacterial effect
  • Acetic acid – the antibacterial effect
  • Lactic acid – helps with lactose digestion
  • Malic acid – increases saliva production
  • Phosphoric acid – for stronger teeth and bones
  • Linoleic acid – lowers your cholesterol levels
  • Palmitic acid – cellular function support

Mixing coffee acidity with sourness

Bad coffee time. Some coffee drinkers connect coffee acidity with that sour taste and unpleasant tummy ache. For them, coffee acidity is something to be avoided at any cost. 

If you take a sip of coffee and feel the unpleasant taste on the back of the tongue, you have a nasty sour coffee problem. The usual causes?

  1. Under extraction

Extraction is the process of dissolving coffee beans in water. The simplest explanation ever! The coffee bean is made of acids, sugars, oils, flavours…and the acids are extracted first. Hence, at the start of the extraction, coffee is very, very sour. You need to finish the whole process, so the sugars and oils can balance the sourness. If your coffee is not extracted, the sour taste from acids will remain dominant.

  1. Under roasted beans

The Maillard Reaction is a simple name for a whole lot of complicated chemical reactions. It is crucial in creating the characteristic flavour and colour of roasted coffee. Underroasted coffee will never get to the Maillard reaction phase and will remain sour.

Important: under roasted doesn’t mean light roast!

  1. Stale coffee

Like any organic compound, coffee dissolves over time, especially when exposed to heat, humidity, air, sunlight. The first thing that goes is the taste. Aromatic oils evaporate, sugars break down, and the nice acids become less nice. Quinic acid is the main culprit here. 

Coffee acidity – an essential part of the flavour

Tasting time. Coffee acidity is that dry, sparkling feeling on the tip of your tongue. The bright nuance that reassures your taste buds you’re consuming fine Arabica grown on higher altitudes. 

The problem? This feeling is not measurable. And you need to have some tasting experience, along with top-quality beans. An inexperienced palate will just label this kind of coffee as sour.

Here are some terms that help describe the coffee acidity:

  • Fruity
  • Tart
  • Sparkling
  • Lively
  • Sharp
  • Zingy
  • Crisp
  • Bright

We have four main types of coffee acids. Take a look at what they have to offer to your taste buds.

  • Citric acids give crisp notes of citric fruit – lemon, lime, orange, sometimes grapefruit.
  • Malic acids will provide you with green apple, pear, sometimes plum or peach notes. They can give a light metallic and sour taste, but not unpleasant.
  • Phosphoric acid gives your drink tangy and sweet notes like mango or sweet grapefruit. In African coffees, it can further enrich the berry notes.
  • Acetic acids give your cup of Joe sharp, vinegar notes. High amounts of acetic acid are unpleasant.

When you hear the term coffee acidity, most likely, it is connected to the taste of coffee, not its pH level.

What is the source of coffee acidity?

Coffee is a complicated plant, and many factors affect acidity levels. Here are the main ones.

Bean origin

The bean origin determines the overall coffee acidity. For instance, Brasilian beans are less acidic and will give you a smoother, nutty taste. On the other hand, Ethiopian beans are highly acidic and produce flavorful, fruity cups. Kenyan coffees have dominant malic acid, while Colombian ones will surprise you with citric acid.

Coffee type

As we already know, there are two primary coffee types: Arabica and Robusta. Yes, even the famous Kona Coffee is Arabica type. Arabica coffee grows and matures slower. The beans are dense, with more flavour and more acidity. 

Robusta beans will naturally be less acidic.

Roasting

Besides taste, roasting also heavily affects the acidity level. As beans are exposed to higher temperatures, they tend to get less acidic. Hence, lighter roasts have high levels of acidity, while darker roasts are lower on the scale. Dark roasts also produce a chemical compound that further blocks stomach acid production. 

However, not every coffee is suitable for dark roasting. If you take beans with light, citrus, and floral notes and roast them till the second crack, they will lose everything that made their flavour special. You must always consider the bean characteristics before you determine the roast level.

Roasting coffee is all about balance, and that’s why we consider it a form of art. 

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Brewing method

The influence that the brewing method has on the coffee acidity is often related to the extraction time. Let’s also not forget that water temperature plays a significant role. Cold-brewed coffee has less acidity, especially when compared to espresso. 

Acidity is not a desirable flavour in espresso, so the espresso beans are usually dark roast.

Grind size

We grind coffee beans to maximize the surface for extraction. Hence, more extracted beans mean more extracted coffee. Coffee made with the finer grind (Turkish coffee, espresso) will always be more acidic.  Coarser grind levels used for cold brew, French press or cowboy coffee will always have a less acidic taste.

Processing

There are several ways to skin a cat and several ways to remove the coffee cherry. Washed coffees are rinsed underwater. This process eliminates the cherry sugar, and bean acidity goes up. Natural and honey processed coffees result in more balanced acid-to-sugar ratios and sweeter coffee.

Water

Source of life, and makes around 95% of your cup of coffee. One of the most overlooked parts of the brewing process.

  • Hard water, rich in minerals, will reduce your feeling of coffee acidity.
  • Soft water (low in minerals) is usually rich in sodium. Thus, your perception of coffee acidity will be enhanced.

How does coffee acidity affect your health?

Acidic coffee doesn’t have to influence your health. But some people will have slight medical problems. The usual ones are:

Although coffee doesn’t cause any of these issues, it can make them worse. 

If you don’t prefer the acidic taste, there are some methods to reduce the coffee acidity:

  • Avoid light roasts. Pick medium or dark ones.
  • Change your coffee brewing method. Cold-brew will produce the smallest level of acidity. Or try a French press. Anything with a coarser grind.
  • Add milk. Milk is 6 on the pH scale. On the other hand, milk can cause you even more problems if you have a sensitive stomach.
  • Opt for decaf. Caffeine is known for stimulating the production of stomach acid. 
  • Try Robusta beans. 
  • Add a pinch of salt to your cup of coffee. Between you and me, I still lack the courage for that step.

Conclusion

Coffee is a magnificent plant. It offers oh so many flavours, notes and aromas. Playing with brewing methods, grinds, beans…will always give you different results. 

Coffee acidity is a vital part of the coffee flavour. It gives sharpness and liveliness to your everyday cup of coffee. Like wine or fine cheese, coffee acidity is an acquired taste. 

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