Coffee acidity refers to the sensory characteristic of brewed coffee influenced by organic acids like citric, malic, and chlorogenic, whose concentrations change with roast degree, grind size, and brewing method. According to a 1985 study published in Zeitschrift für Lebensmittel-Untersuchung und Forschung, out of more than 38 acids contributing to coffee acidity, the primary ones are citric acid (12.2% in roast coffee), acetic acid (11.2%), and high molecular weight acids (8%).
While coffee acidity is an important part of evaluating coffee quality, and one of the main metric that coffee experts and judges use to score coffee quality, high-acid coffee can cause stomach discomfort, discoloration of teeth, and potential health problems in acid-sensitive individuals. Given these potential issues, many people seek ways to reduce coffee's acidity.
These are eight ways to make coffee less acidic.
- Choose Dark Roast Coffee
- Choose Low-Acid Coffee Beans
- Use a Paper Filter
- Use Lower Brewing Temperatures
- Experiment with Brewing Time
- Adjust Coffee-to-Water Ratio
- Use a Coarser Grind
- Add a Pinch of Baking Soda
1. Choose Dark Roast Coffee
Dark roast coffee refers to coffee beans roasted for 11-14 minutes at 465-480°F/240-250°C. This extended roasting results in a darker color, a robust, often bittersweet flavor profile, and lower acidity than lighter roasts. The longer the roasting time of the coffee, the less acidic it becomes. In fact, dark roast coffee has approximately 22% less total acids than lighter roasts, and 11.54% less acidic than medium roasts, according to a 2023 study by Christina J. Birke Rune from the University of Southern Denmark's Department of Technology and Innovation.
The easiest thing a person can do to make coffee less acidic is to replace medium roast coffee with darker roasts. The study, published in Current Research in Food Science, found that the concentration of chlorogenic, citric, and malic acid in arabica coffees decreased due to the breakdown of these acids from heat during roasting, while quinic, acetic, lactic, phosphoric, and glycolic acid increased with the increasing roast degree from lighter to darker. Similarly, a 2020 study by Niny Z. Rao from the Department of Biological and Chemical Sciences at Thomas Jefferson University found that dark roast coffee has lower acidity compared to lighter roasts. Specifically, the pH levels for dark roast cold brew and hot brew were 5.75 and 5.39, respectively, compared to 5.00 and 4.80 for light roast. While pH is a measure of acidity, other factors, such as the types of acids and oils present, also influence how acidic coffee tastes.
For those searching for how to make coffee less acidic, this graph demonstrates the inverse relationship between roast level and acid concentration in coffee, with regional variations in initial acidity levels.
2. Choose Low-Acid Coffee Beans
Low-acid coffee beans refer to coffee beans that naturally contain lower levels of acids responsible for the characteristic acidic taste in coffee, such as chlorogenic acids, citric acid, and acetic acid. A 2011 study by Natalina Bicho published in the International Journal of Food Sciences and Nutrition has shown a significant difference in chlorogenic acid content between Arabica and Robusta coffee beans, with Arabica beans consistently showing higher concentrations, even after roasting decreases levels in both types.
Based on these findings, to make coffee less acidic, using Robusta beans is preferable, as it appears that coffee made from Robusta beans is indeed less acidic than Arabica. The study, titled "Identification of nutritional descriptors of roasting intensity in beverages of Arabica and Robusta coffee beans," found that Arabica coffee generally has lower pH values compared to Robusta, indicating higher acidity. Lower pH values correspond to higher acidity levels. For example, the pH of Arabica coffee roasted for 7, 9, and 11 minutes was 5.12, 4.98, and 5.39 respectively, whereas Robusta coffee had pH values of 5.27, 5.24, and 5.47 for the same roasting times.
Further supporting this, a 2013 study in Ecology of Food and Nutrition by researchers from the Department of Biomass Science and Technology at New University of Lisbon showed that Arabica coffee has 109% higher levels of citric acid and a more pronounced acid flavor compared to Robusta coffee. Specifically, acid flavor scores in Robusta coffee ranged from 1.28 to 2.71, while in Arabica coffee, they were higher, ranging from 2.92 to 5.42.
This table compares the acidity, taste, smell, and overall quality of Arabica and Robusta coffee roasted for 9 minutes.
| Sensory Characteristics | Arabica Coffee Beans | Robusta Coffee Beans |
|---|---|---|
| Characteristic Odor | 5.49 | 4.62 |
| Burned Aroma | 0.94 | 1.13 |
| Citric Acid Aroma | 4.51 | 1.69 |
| Typical Taste | 5.85 | 4.10 |
| Burned Taste | 1.78 | 1.51 |
| Acid Flavor | 5.42 | 2.71 |
| Bitter Flavor | 2.70 | 2.79 |
| Residual Taste | 4.80 | 3.97 |
| Astringency | 3.11 | 2.57 |
| Body | 5.32 | 4.44 |
| Overall Quality | 7.75 | 6.59 |
3. Use a Paper Filter
Using a paper filter, as opposed to a metal filter or no filter at all, helps to make brewed coffee be perceived as less acidic. A paper filter is a disposable filter used in coffee brewing that traps coffee grounds and oils, which can contribute to bitterness and a heightened perception of acidity.
A 2013 study by Alexia N. Gloess from the Zurich University of Applied Sciences found that paper-filtered coffee, such as filter coffee and the Bayreuth coffee machine (traditional Karlsbad method), showed a moderate pH value. Filter coffee had a pH of around 5.6, which is lower than some other methods like French Press but higher than single-serve capsule espresso (Nespresso), which had the most acidic pH of 5.51.
Is espresso less acidic than coffee? Espresso, while often perceived as more intense, is actually more acidic than paper filter coffee. In a 2018 study by Carla Severini from the Department of Sciences of Agriculture at the University of Foggia, American coffee, which typically uses a paper filter, showed lower total titratable acidity compared to espresso and Turkish coffee. This is because of the paper filter's ability to trap coffee oils and some acidic compounds, as illustrated in this image.
4. Use Lower Brewing Temperatures
Lower brewing temperatures, typically below the standard range of 195-205°F (90-96°C), can reduce acidity, bitterness, and astringency in coffee. This approach is one method for those seeking how to brew less acidic coffee.
Multiple studies support the link between lower brewing temperatures and reduced acidity in coffee. For example, a 2022 study by Mackenzie E. Batali from the Department of Food Science and Technology at the University of California found that cold brew coffee, brewed at 4°C (39°F), had a higher pH (less acidic) compared to hot brew black coffee brewed at 92°C (198°F). Additionally, the titratable acidity, measuring the actual acid content, was lower in cold brews.
Similar results were reported in a 2020 study by Nancy Cordoba published in Trends in Food Science & Technology, where cold brews exhibited a higher pH (less acidic) than hot French press coffees. Another study by Giulia Angeloni from the University of Florence in 2019 also confirmed the lower titratable acidity of cold brew coffee, contributing to its sweeter, less acidic taste.
5. Experiment with Brewing Time
Longer brewing times result in higher extraction of chlorogenic acids (CGAs), a significant source of acidity in coffee. The duration of water contact with ground coffee, also known as the steeping time, directly affects how acidic the final brew will be.
In a 2014 study by Iziar A. Ludwig from the University of Glasgow, over-extraction (brewing with an excessive amount of water or for an extended time) with 55 mL of water resulted in 306 mg of CGAs for light roast coffee, compared to 244 mg with a standard extraction using 35 mL of water. For dark roast coffee, over-extraction yielded 96 mg of CGAs, compared to 74 mg with the standard extraction.
The same study also examined 104 espresso coffees served in Italy, Spain, and Glasgow, revealing differences in coffee preparation and acidity. In Italy, they had a more consistent serving size and CQA content, with levels of chlorogenic acids providing a moderate acidity. In Spain, espressos were served in larger volumes, resulting in a higher CQA content and a more pronounced acidity, with CQAs up to 188 mg per cup. In Glasgow, the study analyzed espresso coffees from various outlets, finding substantial variations in acidity, with CQA levels ranging from 6 to 157 mg per serving, reflecting a wide range of roasting and preparation methods.
This table summarizes the median and range of serving size, CQA content, and acidity level of coffee samples from Italy, Spain, and Glasgow.
| Location | Number of Samples | Serving Size (mL) | CQA Content (mg/serving) | Acidity Level (based on CQA content) |
|---|---|---|---|---|
| Italy | 36 | 20 (median) 13-31 (range) |
46 (median) 20-81 (range) |
Moderate |
| Spain | 36 | 66 (median) 34-104 (range) |
142 (median) 92-188 (range) |
High |
| Glasgow | 32 | 31 (median) 13-90 (range) |
59 (median) 6-157 (range) |
Variable |
6. Adjust Coffee-to-Water Ratio
The coffee-to-water ratio plays a crucial role in determining the acidity of brewed coffee. This ratio refers to the proportion of coffee grounds to water used during brewing, where a higher ratio (more coffee, less water) typically leads to a stronger and potentially more acidic cup.
A 2007 study by Susana Andueza from Food Science and Technology, and Toxicology Department at the University of Navarra confirmed the significant impact of coffee-to-water ratio on espresso acidity. They found that increasing the coffee-to-water ratio from 6.5g per 40mL to 8.5g per 40mL resulted in an increase in perceived acidity from 5.4 to 6.4 in single origin Arabica espresso and from 1.6 to 2.0 in Arabica/Robusta espresso blend.
Similarly, a 2023 study by Agnese Santanatoglia et al. further demonstrated that brewing methods with lower coffee-to-water ratios generally produced less acidic coffee, although other factors also play a role. For example, the V60 method, known for its high extraction efficiency, used a coffee-to-water ratio of 1:15 and resulted in a high average acidity score of 7.75. This is likely due to the increased extraction of acidic compounds from the coffee grounds.
In contrast, the French Press method, using a slightly higher ratio of 1:14, yielded a slightly less acidic cup with an average score of 7.38. The Filter coffee method, with the lowest ratio of 1:16.6, resulted in a slightly less acidic cup compared to the V60, with an average score of 7.63. The table below summarizes the coffee-to-water ratios and average acidity scores for each brewing method studied.
| Coffee Brewing Method | Coffee-to-Water Ratio | Acidity Score |
|---|---|---|
| V60 | 1:15 | 7.75 |
| French Press | 1:14 | 7.38 |
| Filter Coffee | 1:16.6 | 7.63 |
7. Use a Coarser Grind
Grind size, ranging from fine (106–200 μm) to coarse (701–900 μm), plays a significant role in affecting the chlorogenic acid content and acidity of coffee. Specifically, finer grinds increase the surface area of the coffee particles, allowing more water to contact the coffee. This can lead to a higher extraction of chlorogenic acids because the increased surface area facilitates the release of soluble compounds. Coarser grinds, on the other hand, which have less surface area compared to finer grinds, typically require longer extraction times to achieve similar levels of chlorogenic acid extraction.
In a 2019 study by Nancy Cordoba from Universidad de La Sabana, it was found that medium grinds (501–700 μm) achieved higher extraction of chlorogenic acids with shorter times, while coarse grinds (up to 900 μm) required longer extraction to reach similar levels of chlorogenic acid extraction but produced coffee with lower acidity levels, with higher pH values (4.90 to 4.92) and lower total titratable acidity (0.33 to 0.90 mg/g chlorogenic acid).
8. Add a Pinch of Baking Soda
Baking soda, also known as sodium bicarbonate, is an alkaline compound commonly used in baking and cooking. Due to its alkaline nature, some people add a pinch of baking soda to coffee to neutralize some of its acidity, potentially reducing heartburn or indigestion. However, this practice is mostly based on anecdotal evidence, and scientific research is limited. While a small amount of baking soda is usually tasteless, adding too much can give coffee a soapy or salty flavor.
Why Is Coffee Acidic?
Coffee is acidic because it contains various organic acids like citric, malic, quinic, acetic, and chlorogenic acids, which contribute to its bright, fruity, and sometimes bitter flavors. The concentration of these acids varies depending on the type of coffee and the roasting process, with some acids decreasing and others increasing during roasting. This complex interplay of acids is responsible for creating the distinctive acidic coffee we know, shaping its nuanced flavor profile. This begs the question: What types of coffee drinks are less acidic for those who prefer a milder taste?
What Types of Coffee Drinks Are Less Acidic?
Here are the nine coffee drinks that are less acidic
- Cold Brew Coffee: Cold brew coffee with coarse ground coffee is less acidic because the long (12-24 hours) cold extraction process results in lower extraction of acidic compounds, making the coffee smoother and less acidic.
- French Press Coffee: French Press coffee is less acidic because the metal filter used preserves oils and fuller body, which balance the acidity, resulting in a smoother taste.
- Drip Coffee: Drip black coffee is less acidic because the filtration and specific brewing techniques produce a balanced flavor profile with lower perceived acidity.
- Aeropress Coffee: Aeropress coffee is less acidic because the controlled brewing process and filter preserve oils and result in a smooth, less acidic cup.
- Nitro Cold Brew Coffee: Nitro cold brew coffee is less acidic because the nitrogen infusion makes the cold brew even smoother and less acidic than regular cold brew.
- Instant Coffee: Instant coffee is less acidic because the production process often balances and mellows the acidity, resulting in a smoother taste.
- Americano Coffee: Americano coffee is less acidic because the dilution of espresso with hot water reduces the concentration of acidic compounds, making the drink smoother.
- Iced Coffee: Iced coffee is less acidic because chilling the coffee reduces the perception of acidity, making it taste smoother and less harsh.
- White Coffee: White coffee, made with the addition of milk or cream, is less acidic because the milk or cream neutralizes some of the acids in the coffee, resulting in a smoother, less acidic drink.
Where To Find Less Acidic Coffee?
You can find less acidic coffee brands like Lifeboost, Puroast, Powerbean Coffee, or Volcanica online or at specialty coffee shops. Alternatively, choose coffee beans from regions like Brazil or Sumatra, known for producing naturally lower-acid coffee.
Can You Buy Less Acidic Coffee at Powerbean Coffee?
Powerbean Coffee does not offer coffee specifically labeled as "low acid." However, opting for a dark roast from Powerbean Coffee is generally recommended, as it is considered less acidic than lighter roasts.
