Ah acid, it’s a constant topic of conversation for some coffee drinkers, and we can understand why. The acidic flavors in coffee are one of the reasons people love this drink so much. From bright citrus and fruity flavors to sparkling notes that dance across your palate, those acidic flavors are enticing for a lot of coffee fans. On the other hand, there are plenty of people who have to avoid acid for health or taste reasons. The issue is that sometimes the flavors we associate with acids and the actual acid content in a cup of coffee do not correlate at all. So what’s the deal?
Acid content in a cup of coffee plays into flavor extensively. In fact, it’s a careful balance. Too much acid leads to sour tasting coffee. If the acid content is too low, the coffee will have a flat, uninteresting taste. Striking that balance is key. The first thing to understand here is that there are multiple kinds of acids at play. Malic, citric, and tartaric acid (along with some other acid compounds) all add unique flavor to the roast. There are also chlorogenic acids, which break down into quinic and caffeic acids. These acids come out during the roasting process, and cause bitterness and a sour flavor. This is why darker roasts tend to be more bitter.
This means that your first step is in determining what acids you want to avoid. From there, you can make informed judgements about acid content based on factors of the coffee’s production.
Origin, Variety, Process
As you (hopefully) know, coffee is a plant! This means that its nutritional content largely comes from the contents of the soil it draws nutrients from. This means that origin plays into coffee acidity very much. Different origins have soil with different acid contents, so if you know that Colombian coffees tend to be grown in soil with higher citric acid contents, you can assume a Colombian coffee will contain more citric acid than an Ethipiopian coffee.
Then there’s variety/species. Arabica coffees tend to be lower in acidity than Robustas, for example. From there different varieties will have their own differences in acidity. Climate and elevation can also play into the equation, with cooler climate coffees tending to be higher in acid content due to their slower development.
FInally, there’s processing.
Washed processing, for example, leads to more acidic flavors. This is because the pulp of the cherry is washed from the bean, so those fruity compounds don’t dry into the bean. This is why washed coffees tend to taste a bit more sparkly and balanced without that sweetness to overpower the acid. This is not a change in the overall acid content however, just perceived acidity.
You can also affect acidity with your brew method. Since coffee extraction is the chemical process of water bonding with molecules in the coffee grounds, it plays a big role in determining overall acidity in your cup. How does this translate to your recipe?
To get a lower acid cup, you’ll want a finer grind time, longer brew time, and lower water temps (but still in the 195-205 fahrenheit range). This lengthier extraction time will allow acids to release during brewing, leading to a less acidic cup. For more of that sparkling acidity, simply reverse those parameters.
In the end though, there’s no way to completely eliminate acids from coffee. The best you can do is make informed guesses as to acid content.