Acidity in coffee
With the advent of a more professional and knowledgeable roasting, a big door opened, allowing a spectrum of new results and insights we get in the end cup. One of those is definitely acidity. But what does acidity mean? Is it something desirable, intended, or does it turn into a defect in the coffee we are drinking?
Let´s start from the beginning. By default, coffee is a bitter beverage. This is an inherent feature of this magical black wine and will remain for eternity. And this is specially the case when we talk about very dark roasts, done either by choice or simply because it was the only available roasting technique that existed (until not so long ago). But because of having better machinery, deeper knowledge and more skilled artisans, coffee roasteries started to be eager to go lighter in terms of roast degrees/levels. And as the rule states: the lighter the coffee is roasted, the more features from the place of origin will be kept; in contrary: the darker it is, the more of these are gone.
So, as coffee roasters started to clinch excellent results with a lighter degree, we were able to enjoy a world of perceived aromas, flavours and notes; and within this light area is where we find the well-known acidity, which goes hand on hand with the fruitiness of those coffees. When we say a coffee is acid, it is not necessarily a bad thing; in fact, can actually be an excellent feature of a well-roasted bean and a subsequently properly brewed beverage. Just think about all citric fruits: those are somehow acid, right? And they are still very tasty. The issue, then, comes in place when that acidity turns into an unpleasant feeling, like when we lick a lemon. This is not so nice to feel in our mouth and we even tend to reject that. But when we squeeze that lemon and add a bit of water, this acidity is not only more tolerant but also appears as something expected to find in it. Otherwise would not be a lemonade!
So, the same happens with the acidity in an espresso (I leave all milk based products aside due to the fact this immediately reduces/eliminates this feature thanks to its sweetness). This should be something subtle that enhances the citric aspects of the infusion, so you can clearly perceive notes of rosehip, cranberries, oranges. It should allow you to still drink it until the end; it should kick at the very beginning and then slowly lower its power. But when this feeling becomes already something sour, too intense, too pronounced and lasting way longer than expected, we are then in front of a problem which can not only cause a bad experience in the moment, but also a consumer which can be potentially lost forever.
Not everyone is keen (or even prepared) for having a fruity espresso because of that fine line between the tasty and the unpleasant. Therefore, when this is identified as a problem, or when you did not want to have that taste at all, what are the causes for such an undesired result and how can we solve it? Well… we have basically 2 origins:
1. Undeveloped roast: when the roaster finished the roast either before first crack or when it went extremely fast/aggressive while roasting a coffee. Solution: as a coffee drinker, we cannot influence this at all.
2. Under extracted brewed espresso: this happens when we have a very fast extraction out of the machine. Visually, precisely when the coffee comes out very watery, with very little body or not at all. Potential solutions:
a. Go finer in the grind settings: this guarantees a more even water distribution with the coffee in the puck and avoids channeling. The water should have a good resistance to pass through the ground coffee (be careful not to block it and go the direction of over extracting it). This can also apply to ensure a slower extraction, reducing sourness in very light roasts.
b. Keep the same grind settings but add more ground coffee in the puck: maybe it is only a matter of a bigger dose. As a reference, always have in mind the rule of extraction: you should get 25ml of liquid coffee yield in the cup in approximately 25 seconds. This could be also useful for very light roasts in order to achieve a longer/slower extraction and to therefore reduce sourness.
There are many options for you to play around at home with citric coffees or even very light roasts. As these will have more acidity by default, you can still reduce it with your own hand. And as I always like to mention, at the end of the day, if the cup makes you happy, it is a well done cup! I invite you to take the plunge and play with the tools you have, which I am sure there are more than enough.
I hope you liked the read. In case you want to share your experience or simply ask questions, please don´t be shy and get in touch with me: I love to help. Let´s talk coffee!