Contrary to popular belief, coffee is not an exclusively bitter beverage. Coffee actually contains a wide variety of acids, which can be more or less emphasized by roasters and baristas.
But coffee consumption patterns are changing. Recent years have witnessed two phenomena:
- Roasters lighten their roasts
- Espresso machines with integrated grinders are becoming increasingly popular
These two elements, which are quite favorable from a quality point of view, offer consumers an unprecedented challenge. In fact, it is now often necessary to adjust the machine for your coffee.
Gone are the shamaneries of Grandma’s sock juice, and goodbye to the simplicity of capsules!
As mentioned above, coffee contains many acids which, if overemphasized, can become unpleasant. But how do you know if the acidity you feel is just the expression of a particularly fruity terroir, or an unbalanced recipe?
Let’s start with a few basics:
The acids in coffee
Acidity, sometimes confused with bitterness, is not antithetical to bitterness; on the contrary, it complements it, as in grapefruit.
The acidity is clear at the beginning of the mouth, as soon as the coffee comes into contact with the palate. What remains in the mouth after swallowing is bitterness.
But acidity itself can take many forms. Here are some of the acids most commonly found in our favorite hot beverage:
- Malic acid – Apple, cherry
- Citric acid – Lemon, raspberry
- Lactic acid – Fresh cheese, yoghurt, creamy cheese
- Acetic acid – Vinegar, wine, result of grain fermentation
- Tartaric acid – grape, pineapple, tannic
Not all of these acids will always be perceptible at the same time. They depend on the terroir in which the coffee is grown. A Guji coffee (Ethiopia), for example, will have a more pronounced acidity potential than a Bob o’link (Brazil).
However, these compounds are only organic acids, which have a direct impact on taste, and there are actually over thirty of them present in coffee.
Chlorogenic acids are also available as supplements, and will mainly influence the pH or “chemical” acidity of your drink. If you want to avoid stomach upsets, these are the ones to avoid. 1
So we prefer gentler, less concentrated methods such as Chemex. You can also lower the temperature of the water used for extraction, or infuse completely cold or at room temperature.
It’s also worth noting that, generally speaking, a higher growing altitude results in greater acidity potential, as does the presence of a volcanic terroir.
The roaster can also mask a coffee’s acidity by further roasting. These heat-sensitive compounds will gradually disappear with longer cooking, replaced by bitter compounds.
Conversely, a lighter roast will bring out the fruity (and therefore acidic) flavours of a coffee. The choice is yours!
And while we’re on the subject of choice, it’s impossible not to mention thatArabica naturally has more acidic compounds than its neighbor Canephora, of which the well-known Robusta is a subspecies.
Obviously, any addition to the coffee will lower the acidity level: water to make it longer, milk to soften it, even sugar (preferably brown cane sugar)!
But if you insist on sticking to our classic black coffee, you’ll need to work on your recipe.
What’s a coffee recipe?
It’s simply the ratio between the quantity of coffee used and the quantity of water passing through it, coupled with the size of the grind. These three elements form the basis of a recipe.
When we make coffee, we extract aromatic compounds with water. As this extraction is non-linear, it’s precisely these acids that are extracted first, followed by the bitterness.
So it’s up to us to balance our 3 revenue items.
Attention The extraction time is a recipe element only in the case of infusion (Coffeemaker piston); the rest of the time, it’s a control value resulting from the other parameters.
How do I set my recipe for good coffee?
Acidity in coffee must be pleasant and balanced with bitterness, sugar, body…
If your coffee is too acidic, harsh, vegetal, even salty… This is called under-extraction. And this is often the case with espresso machines. Indeed, the pressure applied favors the extraction of acidic compounds.
You will therefore need to extract more aromatic compounds to rebalance the drink. This involves increasing the surface area and contact time between the water and the coffee.
The solutions are simple:
- Refine the grind, and you’ll even gain in stature.
- Increase the amount of water passing through the coffee.
- Reduce the amount of coffee.
On most recent machines, all these parameters are more or less accessible, so you can play around with them. Sometimes a simple grind adjustment will suffice, but often several tests are required.
Be careful not to increase these parameters too much either, otherwise you’ll fall on the other side of the balance, over-extracting, and your coffee will become bitter.
If so, don’t panic! All you have to do is go back slightly on your settings to achieve balance. A scale can be an invaluable companion for reproducing the exact settings you need.
Of course, this advice applies to all brewing methods, manual or automatic, even though brewing methods (Cold Brew or French press) can benefit from a longer brewing time to balance the extraction.
If, despite all these tests, the coffee is still too acidic for your taste, it’s time to switch to a coffee with a fuller-bodied origin, such as Central America or Asia, and possibly a darker roast to reinforce the body… Or change your machine for a model that will enable you to grind your coffee finer.
Inexpensive machines and grinders generally have trouble grinding fine enough, especially for espresso. And tinkering with your machine to fine-tune the grind is a lengthy adventure, fraught with pitfalls, and entails a loss of warranty. 3
My little tip
My little bonus tip is to use spring water with a low mineral content if you want to emphasize the acidity of the terroir, or water with a higher magnesium content if you want to emphasize the body.
Ultimately, you have the power. It’s your choice of origins, roasts, terroirs and settings that will enable you to get your energy source just the way you like it. Because that’s the best kind of coffee.