When you think of the word acidity your mind probably associates that word with tangy, sour, sharp or bitter – but, I bet you don’t immediately think of coffee? The strange thing is, coffee does often get branded as acidic, but in reality, a cup of coffee is only around five on the PH scale (1), which makes coffee less acidic than say a can of soda, a beer, or a glass of orange juice.
But this is where it gets interesting. Acidity is one of the key attributes that make up a cup of specialty coffee. It’s loved by third-wave coffee drinkers, and it’s often praised by competition judges around the globe, but, at the same time, acidity is also a cause for confusion in the coffee world.
What exactly is coffee acidity? Why can you taste it in coffee? And how can you adjust the acidity levels by roasting and brewing?
If you’re looking for the answer to some or all of these questions, keep on reading because in this article I’m going to lift the lid off the whole coffee acidity confusion.
What is Acidity in Coffee?
Acidity isn’t easy to define and pinpoint, sure we have plenty of adjectives for it, but none of those can thoroughly explain what acidity is. Acidity can be described in many forms making it hard to define. For example, it can affect the taste as well as the aroma, and it can even be described as “mouthfeel” when it comes to coffee.
Acidity can also be a chemical compound, and the type of compound will affect the taste of your coffee. It could make your cup taste out of this world, but it can also be the worst cup you’ve ever had.
For example: if your cup of coffee is too acidic to the point that it becomes sour most people aren’t going to enjoy it. And on the flip-side, if your coffee doesn’t have enough acidity, the coffee is going to taste flat.
So it’s easy to see whey there is so much confusion surrounding this term and coffee – it’s a fine line between the greatest and the worst cup of coffee you’ll ever have.
You don’t have to be a fully-fledged chemist to understand the basics of acidity in relation to coffee and a little bit of knowledge can help coffee roasters and baristas to get the best possible flavors they can out of the humble coffee bean.
Acids Found in Coffee
The acid in coffee can be broken down into two categories – Chlorogenic and Organics.
Chlorogenic acids are typically broken down during the roasting process into another set of acids – caffeic and quinic acids.
This is where it can get tricky during the roasting process because quinic acids don’t taste good and it’s these acids that can give your cup of coffee bitterness and sourness that will guarantee you don’t take another sip.
Darker roasts, for example, tend to be more bitter and lighter roasts are typically more fruity.
Again – it’s a fine line: Too much or too little of this type of acid can make a massive difference to the taste of your coffee.
Organic acids found in coffee can include malic, citric, acetic, and tartaric acids. These are the good tasting fruity acids that we all love in our cup of coffee.
Each of these compounds has their own unique attributes to a cup of coffee.
- Malic acid can be likened to the same kind of acid found in fresh green apples.
- Citric acid, as you may have guessed, can be compared to citrus flavors. Think oranges, lemons, oranges, and nectarines.
- Acetic acid offers a less pleasant taste and tends to be more vinegary.
- Tartaric acid can add a grape-like taste to your coffee.
Why Some Green Beans More Acidic Than Others?
Getting rid of acidity in coffee entirely is almost impossible, no matter how you brew or roast your coffee beans, some coffees will always have more organic acids than others.
Many factors come in to play such as the origin of your coffee beans, the processing methods used, and not forgetting the climate that can have a big difference in the acidity of your coffee.
Coffee Bean Origin
Where your coffee comes from plays a huge role in just how much acidity will be present in your beans. Example: Each origin has different soil compositions; coffee sourced from Kenya tends to contain more Malic acid, whereas Colombian coffee is typically high is Citric acids.
Climate and Elevation
Where and how high the coffee is grown can also play a role in the acidity. For example, cooler temperatures will allow for the coffee to ripen slower, which in turn will produce more complex flavors. Cooler temperatures (higher up a mountain) tend to lean towards a more acidic coffee bean than those grown in warmer climates (lower down the same mountain).
Coffee Bean Variety and Species
The type of coffee bean can also play a role in just how you perceive the acidity in your cup of coffee. For example, Arabica typically contains far less chlorogenic acids, which decreases its amount of acidity.
This can be down to genetics or where the coffee was farmed and processed. Some coffees are better suited to colder climates, and others prefer warmer growing conditions.
Processing of the Coffee
All of us refer to coffee as a bean – wrong. Coffee is actually a seed of berry known as a cherry. This seed (coffee bean) is locked inside of the berry and removing it can be tricky. The process used to extract the bean will affect the final flavor and acidity.
A common method is a wet or washed process. This is where the coffee is pulped and then rinsed in water, which in turn removes layers of fructose and sucrose (sweetness). This method allows for the acidity to be prominent, and it’s not diminished by sweetness.
Other natural processing methods will leave the coffee completely intact while it dries, which in turn, gives the coffee much more sweetness that then overpowers to underlying acidity.
How do you Control Acidity During Roasting?
It’s impossible to create a flavor during roasting or even brewing your coffee that the bean didn’t already have to start with. But, it is possible to roast your coffee in such a way that you can either highlight or reduce the amount of acidity found in the bean.
The roast level plays a vital role in just how acidic your coffee will be. However, don’t be fooled into thinking that roasting is simply how long you keep the beans in the roaster – cha-ching, done!
Manipulating the airflow and the heat all play a role in the characteristics of the final roasted coffee. High temperatures typically help to remove acidity, but if you take the temp too high, you’ll burn your coffee beans. It’s all about the right balance depending on the type of beans you have.
You should aim for an early first crack that doesn’t last too long – this is something that goes hand-in-hand with high heat. But also don’t forget, too early or too short can also lead to sourness.
It takes practice, and you need to understand your coffee beans and be able to monitor the heat with a trained eye throughout the roasting process to end up with a cup that’s not only balanced but allows the acidity to shine.
How to Control Acidity in Coffee Brewing
Imagine you’ve got a fresh bag of high-altitude Ethiopian coffee packed with acidity and the roaster has highlighted this acidity perfectly. Will this mean that you’re guaranteed a great-tasting cup? Not necessarily. If you brew it incorrectly, you could possibly still end up with a flat brew.
But what is coffee extraction? And how does it affect the taste of your coffee?
As soon as the boiled water makes contact with your freshly ground coffee, the aroma and flavor compounds start to diffuse in the water – this process is what we call “extraction.”
The amount of extraction will determine the aromas and flavors found in the final cup. It’s the acidic and fruity flavor notes that are extracted first which are then followed with sweetness and then finally bitterness.
So, simply put, under-extracting will produce more of a sour taste since it doesn’t contain the sweetness combined with a tiny hint of bitterness to balance out the acidity.
On the other hand, over-extracting your coffee will lead to a bitter cup because all of the acidity and sweetness has been overwhelmed. – it’s all about finding that perfect balance.
Controlling the extraction can be simplified and broken down into three basic rules.
- A coarse coffee grind will result in more acidity, whereas a finer grind equals more bitterness.
- Also, a longer brew time will allow for more time for extraction. Shorter brewing leads to more acidic, and longer ones tend to be more bitter.
- Water temperature also plays a role. Using hot water will allow for extraction to happen a lot quicker, but on the flip side using cooler water won’t allow for the acids to extract from the coffee.
If you want a more acidic cup of coffee, aim for a high water temperature combined with a coarse coffee grind with a short brew time. Use a finer grind and brew for longer if it’s coming out too sour. Take a peek over here if you’re looking for the best low acid coffee brands.
It’s all about balance if your cup doesn’t taste right to you tweak any one of the brewing variables to brew to best tasting cup for you.