The Beginner's Guide to Coffee Acidity

The Beginner's Guide to Coffee Acidity

WRITTEN BY: ZOE DUMAS

Whether we notice it or not, acidity is a fundamental pillar of flavor science. It balances out rich textures and decadent flavors, making the food or beverage, as some put it, sing. Coffee is no different: without acidity, coffee comes across as flat, basic. Acidity, conceived of in this way, is a lively presence that brings all a coffee’s flavor notes into harmony. When a coffee is described with words like “tangy,” “lively,” or “vibrant,” this is what the taster is trying to convey.

Of course, when we hear the word “acidic,” pleasant wouldn’t be the word on everyone’s mind. Acidity can be unpleasant and astringent, an assault on the senses that makes any food or drink unpalatable. It’s important to find a coffee with enough acidity to balance the cup without puckering your entire face.

Your experience of coffee as “acidic” may not be completely related to its empirically measurable acidity. Yes, coffee is acidic at pH 5, but those sour notes you taste may be indicative of something other than the bean’s chemical makeup. By knowing what coffees to look for and how best to brew them, you can find your new favorite low-acid brew. 

Where does coffee’s acidity come from?

Coffee goes through a lot on its journey from farm to cup: variations in any step in this process could contribute to a coffee’s perceived acidity. Like the grapes used to make wine, the place where coffee plants are grown contributes to that coffee’s acidity. The types of acid present in any given coffee do vary regionally: for example, Kenyan coffees typically have higher levels of malic acid, translating into their green appley taste.

Origin, though, is just part of the formula. While there are variations in acidity depending on origin, a much more telling indicator of a coffee’s acidity lies in the land itself. At higher elevations, cooler temperatures allow the beans to develop much more slowly than those grown lower, meaning they gain more of those fruity, acidic characteristics of modern specialty coffee.

As you’ve probably already learned in your coffee education, processing is another point in a coffee’s journey that can have immense consequences on its final flavor. Washed coffees are stripped of their fruity pulp manually; consequently, the coffee bean has less time to absorb the layers of sucrose and fructose from that fruit and comes out more acidic than, say, a natural or honey process coffee.

Roasting is the next step, and it should come as no surprise that perceived acidity is affected by it. A general rule of thumb is that a darker roast will be less acidic because the roast qualities mask the more acidic notes inherent to the green coffee. Careful, though, not to go too dark: over roasting can cause the organic acids in coffee to break down into bitter chlorogenic acids, instead.

Brewing is where you have the most control over how acidic the final cup will be. First, the size of your grind has a direct effect on the coffee’s acidity. A smaller grind size exposes more of the coffee’s surface area to water, resulting in greater acidity extraction than in coarser ground coffee.  Next, water temperature: your brew water’s temperature directly determines the “release and diffusion of compounds,” and therefore perceived acidity, in the final cup. Finally, is brew time. The longer water is in contact with your ground coffee, the lower the acidity. The fact that all of these factors have been shown to have a significant effect on the final brew indicates that adjusting these to fit your needs is doable. Whether you’re making micro-adjustments to perfect your pour-over or switching to a completely different brew method, you can make your perfect cup.

Effects of acidity

Coffee’s acidity doesn’t affect everyone, but some drinkers experience discomfort related to it. Typically, this is because it is aggravating a preexisting health condition like acid reflux, gastric ulcers, or IBS. If you don’t have one of these and still experience discomfort, however, there are options for reducing acidity in your brew.

Taste-wise, acidity ties together all the other flavors present. Not only is it the bright, tart taste, but it’s the slight drying effect at the back of your palate, all mellowed out by a sweet finish. When present in just the right amount, acidity is a good sign of the coffee’s quality. As many of us have tasted, however, acidity can be too much. A hint of Meyer lemon is one thing, but no one wants to finish their coffee feeling like they just bit into one.

How to reduce acidity in coffee?

With each cause of coffee’s acidity laid bare, it’s easy to see the solutions that can get you to caffeinated excellence: carefully choose your coffee and optimize your brewing. When choosing a new bag of beans, take note of a few things. What’s it’s origin? Be on the lookout for countries at lower elevations, like Thailand and Brazil. How was the coffee processed? Natural and honey processed coffees are naturally sweeter and have what some describe as a “round” acidity: it’s present, but mellow and undistracting. Finally, check the roast level. You’ll likely want to stick with a medium or darker roast, as lighter roasts tend to have a sharper, more vibrant acidity that stands out in the final cup.

Now that you’ve picked your coffee, it’s time to brew! Brewing methods that rely on a coarse grind, like French press and cold brew, are reliably lower in acidity than some others. That said, you absolutely can and should experiment with variables like grind size, water temperature, and brew time, regardless of brewing method, to find a level of acidity that pleases you.

Start from a standard recipe for your given method. If you don’t have one, check out our brew guides for a starter. Make a cup and assess the taste. Is it bitter? Sweet? Acidic? Maybe make the grind one notch coarser or finer. You can also try a cooler brewing temperature, even if it’s just by one or two degrees. Or adjust the brew time; maybe let that French press go an extra 30 seconds before the plunge. When making pour overs or other similar methods, try brewing for the first few seconds into a separate vessel to keep out the most acidic part of the brew. Every time you make coffee, keep tabs on the parameters you used when making it and the flavors that result. This way, you can continue your coffee experimentation over time, and, once you find your perfect cup, easily replicate it.

Coffee is naturally acidic, and there isn’t a way to truly change that; however, our perception of its acidity isn’t necessarily in line with the true acidity of the bean. Thankfully, we can have the tasty, low-acid coffee of our dreams with careful purchasing and consistent brewing. If you’re not sure where to start looking for a new bag, check out our House Blend, Sanuk Espresso, and Ma Oh Jo. In each of these coffees, you’ll find complex flavors with subtle acidity that will liven up your morning, rather than starting it on a sour note.   


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