Understanding Low Acidity Coffee

You may have recently seen the phrase “low acidity coffee” floating around the internet. Many wellness-focused brands use it to market their products to those of us that struggle with the broad spectrum of acids found in a cup of coffee. However, are there certain coffees that actually justify this denotation? We decided to put this to the test! Evan Kluender’s experiment covers measured acidity vs. perceived acidity, the relationship between acidic taste and pH, and how to brew a balanced cup that everyone can enjoy.

Acidity in Coffee

Acids found in coffee can lead to heartburn, bloating, and gastrointestinal discomfort—all things you generally want to avoid first thing in the morning. Some creative types have worked around this problem by using mushroom or chicory coffee. But if you love coffee as much as we do, swapping out your morning brew for something that’s not actually coffee might feel like a kind of sacrilege. Still, the existence of these products means that there is a market for low acidity coffees.

This made us wonder if great tasting coffee and low acid coffee intersect anywhere on the Venn Diagram of specialty coffee. If you’re in the industry, you may be asking: Isn’t acidity in coffee a good thing? In most cases, you’d be right! Acidity is a highly sought after trait in the world of specialty coffee, and for good reason. Many compounds that make coffee taste the way it does are acids. For example, citric acids most notably lend themselves to a citrus-like tangy acidity, and malic acids are responsible for the soft acidity more in line with apples or pears. There are a myriad of acidic compounds present in coffee that will make or break a cup and all serve a purpose.

“Low Acid” Coffee

So, what kind of coffee do you have to use to justify the “low acid” denotation? Acidity in coffee has been studied for a long time, and many agronomic and academic institutions have researched it extensively. A quick search will result in a plethora of information about pH levels in different origins at different roast levels. One would quickly determine that coffees with the lowest acidity are low grown, decaffeinated, cold brewed, dark roasted, or any combination of these.

With such a high volume of information, we decided to leave the science to the scientists. Instead, we set out to find that sweet spot where those with sensitivities can still enjoy the full spectrum of flavors in a hot cup of coffee. We geared our tests toward answering two questions: Is there a difference between a coffee’s measured acidity and its perceived acidity? If so, are there coffees out there that taste acidity yet measure higher on the pH scale?

Coffee Acidity Experiment

To begin, we put six unique coffees on the cupping table, each roasted at three distinct levels. We first scored them to determine the perceived acidity of each cup. After recording our scores, we went through each coffee again to test the pH levels and find its measured acidity.

It’s important to note that this test exclusively measured acidity in immersion brewed hot coffee, a method traditionally used for cuppings. The roast levels used were a cupping style roast, a production style roast, and a dark roast. A cupping roast is a light roast that is roasted just enough for flavors to develop, typically used for quality control. Additionally, we define a production style roast as the “sweet spot” for a given coffee and is roasted to bring out the full depth of flavor in a coffee. Lastly, our dark roasts are pushed slightly past full-medium, not so far that the beans begin to develop oils.

We recognize that utilizing profiles relative to the coffees introduces multiple variables to the experiment. However, we chose this route because it ultimately provided us with the most relevant information to determine which of our coffees, if any, could be considered low acid.

The Expected Results

In many ways, the results were exactly what we expected they’d be. Lower-grown coffees, like Brazil Cerrado, measured the lowest perceived acidity as well as the highest pH levels (least acidic). Higher-grown coffees, such as those from Kenya, achieved the highest cup scores for acidity and measured the lowest pH levels (most acidic). These results fell in line with the understanding that higher-grown coffees are significantly denser than their lower-grown counterparts. This is largely because coffee grows more slowly in cooler climates at higher altitudes, allowing the beans to absorb more nutrients from the soil. In turn, this leads to a higher concentration of acidic compounds.

Similarly, dark roasted coffee measured the highest pH levels across the board. This illustrates that these acidic compounds break down at high heat. By the time a batch of coffee beans achieve a dark roast profile, there is a much lower volume of acidic compounds to be extracted.

The Unexpected Results

While these are hardly groundbreaking discoveries, we did find a few surprising results! We discovered that perceived acidity does not always coincide with measured acidity. Our washed Kenyan actually measured the highest perceived acidity on the production roast. However, it measured the highest pH level on a cupping profile. We would never consider a high-altitude Kenyan coffee as low acid without it being heavily dark roasted. Therefore, it’s very interesting that a washed Kenyan would be perceived to have higher acidity at a deeper roast level despite its lower pH level.

Conversely, we tested a wet-hulled Sumatran that had equally perceived acidity across the board, even as the pH level dropped with darker roast levels. We can explain this by its processing, however. In Sumatra, coffee cherries take on flavors from their environment when wet-hulled. Therefore, they have very earthy notes that likely mask much of the acidity present in a cup of coffee. By and large, we perceived washed and wet-hulled coffees to have lower acidity levels than their washed or honey processed counterparts. This wasn’t so surprising as fermentation almost always results in lower pH levels in food and beverages.

Final Thoughts

While some of our findings were enlightening, they did not reveal any surprisingly low acidity coffees from our test group. If you’re looking for a lower acid cup of coffee, you should probably stick with a washed or wet-hulled coffee. Furthermore, you’ll still want coffee grown at a relatively low altitude or roasted fairly dark.

Lastly, we’ve got some upcoming arrivals that are easy on the stomach and present interesting cup profiles! We don’t feel many of our coffees constitute a “low acid” cup. That being said, the coffees that measured the highest pH levels are, therefore, our lowest acidity coffees. Plus, we included a couple of our highest acidity coffees! These are great options if you’re looking for a pop of brightness in your cup.