Is Coffee Acidic? The Ultimate Guide to Coffee pH
There’s a lot of talk that coffee is an acidic beverage, but is it really?
While this is mostly true, how acidic your coffee is depends on a lot of factors. From demystifying the pH scale to comparing the acidity of coffee to other common beverages, we'll explore how factors like roast levels, origin, and even your local water influence your morning ritual's acidity. And if you are sensitive to acidity, we'll throw in some tips on how to make your coffee less acidic.
So, grab your favorite brew as we uncover the untold secrets behind the acidity of your favorite caffeine fix!
Acidity and the pH Scale 101
Don’t worry; this isn’t going to be a complicated science lesson. We’ll keep it simple.
If you already know what the pH scale is, skip down to the next section.
The pH scale is a way to measure how acidic or alkaline a substance is. It ranges from 0 to 14, with 7 being neutral (distilled water). Numbers below 7 mean the substance is acidic, and those above 7 mean they are alkaline.
Lemon juice is very acidic, while bleach is a very alkaline substance.
Something to remember is that the pH scale is logarithmic. In other words, compared to a substance with a pH of 7, a substance with a pH of 6 is 10 times more acidic and a substance with a pH of 5 is 100 times more acidic.
If you want to understand this further, check out this more technical explanation.
Is Coffee Acidic and What Is Its pH?
Coffee generally has a pH ranging between 5 to 6, so it’s on the acidic side.
Why did I say “generally?” That’s because different types of coffee drinks tend to have varying pH values. Here is the pH value of some different coffee drinks.
- Espresso pH: from 5.11 to 5.65 based on values measured in an Indonesian study (1).
- Drip Coffee pH: from 4.85 to 5.10 based on a Thomas Jefferson University study published in Scientific Reports (2).
- Cold Brew Coffee pH: from 4.96 to 5.13 based on a Thomas Jefferson University study published in Scientific Reports (2).
- Milky Drinks pH (including lattes and mochas): from 6.26 to 6.36 based on dental data (3).
- Coffee with creamer pH: about 6.75 (3)
Note that milk is still slightly acidic, but less acidic than coffee itself. So it has an overall positive effect on the pH of black coffee.
Further, it’s important to remember that the pH also depends on the roast type, water, and other factors. Two drip coffees could have vastly different pH values. Low-acid coffee beans are also popular options and may have a slightly higher pH of 5.5+(4).
Now, let’s take a look at the approximate pH of other liquids and materials and see how they compare with the pH of coffee drinks. The following values were obtained from the US Geological Survey (5) unless otherwise indicated. I've bolded some substances of interest.
| Substance or Drink | pH |
|---|---|
| Battery Acid | 0 |
| Lemon Juice, Vinegar | 2.0 |
| Coca-Cola or Pepsi | 2.5 |
| Rosehip tea | 2.88 (6) |
| Black tea peach flavor (Nestea) | 2.99 (7) |
| Orange Juice, Soda | 3.0 |
| Drip Coffee | 4.85-5.10 (2) |
| Cold Brew Coffee | 4.96-5.13 (2) |
| Espresso | 5.11-5.65 (1) |
| Milky Coffee Drinks | 6.26-6.36 (3) |
| Coffee with Creamer | 6.75 (3) |
| Clean Rain | 5.6 |
| Milk | 6.5-6.8 |
| Black tea | 6.75 (7) |
| Pure Water | 7.0 |
| Yerba Mate | 7.10 (7) |
| Baking Soda | 9.0 |
| Green tea | 7.0-10.0 (8) |
| Soapy water | 12 |
| Bleach | 13 |
If you are more of a visual person, check the chart below comparing the pH of coffee drinks versus other substances.
Quick Takeaways
- While coffee sometimes gets a bad rep for being acidic, it isn’t that acidic.
- Regardless of the type of coffee drink you enjoy, the pH will generally range from about 5 to 6. Coffee drinks with milk typically have a pH of 6 to 7. Adding milk to your coffee reduces the acidity.
- Coffee can be about 100 times less acidic than orange juice, and several thousand times less acidic than lemon juice.
- Coffee is about 10-100x more acidic than pure water.
- If you drink Coca-Cola and don’t get a stomach ache, then you can’t complain about coffee being too acidic! 😉Coke has a pH of 2.5, making it hundreds of times less acidic than typical black coffee drinks, and thousands of times less acidic than milky coffee drinks!
Why is Coffee Acidic?
Coffee’s acidity can be attributed to its composition of various acids, such as citric, acetic, quinic, chlorogenic, malic, formic, and phosphoric acid (9).
- Citric Acid: Citric acid is commonly found in fruits. In coffee, it contributes to the beverage's bright, sour, and citrusy notes (10). Lighter roasts tend to preserve and accentuate these citric flavors, making them more prominent in the cup. The darker a roast goes, the more citric acid that is broken down (10) (11).
- Acetic Acid: Acetic acid can add a sharp, vinegary note to coffee (10). Its presence is generally low, but lighter roasts do present less acetic acid than darker roasts (10). In a small amount, acetic acid leaves a clean and pleasant taste. Overly fermented green coffee beans may be higher in this type of acid, but roasting darker can break it down.
- Quinic Acid: Quinic acid can lend a somewhat bitter, astringent quality to coffee (10). This acid develops when brewed coffee is exposed to oxygen for too long. Have you ever wondered why you can’t simply heat up a coffee that’s been left out for hours and have it taste the same as when it was just brewed? Quinic acid is your answer. Yuck! Darker roasted coffees tend to have less quinic acid (10).
- Chlorogenic Acids (CGAs): Chlorogenic acid significantly contributes to coffee's overall acidity resulting in different levels of astringent, sweet, and sour tastes (12). Robusta coffee beans tend to have much more than Arabica beans when green or when lightly roasted (10). If you’ve ever felt that bitterness on the back of your tongue, that’s most likely chlorogenic acid doing its thing!
- Malic Acid: Malic acid is responsible for fruity and tart apple-like notes in coffee (13). The roasting process doesn’t affect this acid so much (10). It’s mainly produced within the plant itself.
- Phosphoric Acid: This acid is present in trace amounts but it's one of the most potent acids found in coffee (14). It can enhance coffee's overall acidity and leave a slight tingle on your tongue. The amount of this acid mainly depends on the coffee fruit's growth rate (15).
- Formic Acid: This acid leads to a bitter, fermented, and pungent taste (10). Robusta coffee has considerably larger amounts of formic acid when compared to Arabic coffee, and it increases with roast levels (10).
Pro Tip:
Pick dark roasts if you are trying to drink less acidic coffee. At least some of the acids responsible for coffee’s lower pH will be broken down during the roast process.
While many fruits use high acidity as a defense mechanism against predation, coffee doesn’t necessarily follow this rule. In certain plants, high acidity can deter animals from consuming the fruits, as the sour taste can be unpalatable or even harmful to some animals.
For coffee, caffeine is its primary defense mechanism (16). It’s a natural insect repellent and acts as a chemical defense against pests. The higher in altitude that coffee grows, the less important caffeine becomes. Funnily enough, caffeine is often the culprit for upset stomachs among coffee drinkers, not the acidity.
What Factors Affect Coffee Acidity?
There are so many factors that can make your coffee either tangy or mellow, it can be difficult to know where to start. In this section, we break down how several elements affect the acidity in your cup of joe, moving that pH number up or down.
These factors are:
- Coffee bean variety
- Origin
- Processing Methods
- Climate and Elevation
- Roasting Levels
- Grind Size
- Brewing Method
- Your Local Water
Now, let's go over these factors to understand how they impact coffee acidity.
1. Coffee Bean Variety
The type of coffee bean you choose has a profound impact on acidity. Arabica coffee beans are generally known for their bright, acidic flavors, while Robusta beans tend to be less acidic and more bitter.
However, judging the acidity level of a substance by taste alone is unreliable. For example, the bitter-tasting Robusta coffees contain higher amounts of organic acids (formic and acetic acids). They also contain higher amounts of chlorogenic acids (10).
Within Arabica, there are certain varieties known for being more acidic. Gesha is one example.
2. Origin
The region where coffee is grown greatly influences its acidity. High-altitude regions often produce coffee beans with increased acidity due to slower fruit maturation. Ethiopian coffees, for example, are celebrated for their vibrant, fruity acidity. Coffee beans from Brazil usually have a milder, nuttier profile.
3. Processing Methods
The way coffee cherries are processed can influence acidity. Washed processing tends to highlight acidity, as it preserves the bean's natural characteristics. In contrast, dry (or natural) processing can reduce acidity by introducing earthy and fermented notes. Dry-processed coffee tends to focus on sweetness over acidity.
4. Climate and Elevation
The microclimate and elevation of a coffee farm play a pivotal role in determining coffee acidity. Cooler temperatures and higher altitudes tend to yield coffee beans with more pronounced acidity, whereas lower elevations may produce milder, less acidic beans.
5. Roasting Levels
Roast levels significantly impact acidity. Lighter roasts maintain the coffee beans' natural acidity, allowing it to shine through. Darker roasts often reduce acidity in favor of deeper, roasted flavors. Certain acids are broken down in the roasting process through chemical processes, while others aren’t affected at all.
However, note that the content of organic acids in Robusta coffee increases with roast level, mainly due to acetic acids forming during roasting (10).
6. Grind Size
The grind size affects the rate of coffee extraction during brewing. If you want less perceived acidity, use a finer grind size. More characteristics beyond acidity will be highlighted, such as sweetness and body. When the grind size is very coarse, water will pass quickly, producing an acidic or sour-tasting cup.
7. Brewing Method
Methods like certain pour-overs and the AeroPress often highlight acidity.
Cold brewing coffee typically results in a milder, less acidic brew. The extended steeping time and cold water reduce the extraction of acidic compounds, leading to a smoother, sweeter, and less tangy coffee.
Espresso tends to have a concentrated and bold flavor profile. While it can still feature acidity, it is often more balanced and less pronounced than in other brewing methods, thanks to the quick extraction.
8. Your Local Water
The pH and mineral content of your local water can subtly alter the acidity of your coffee. Soft water may lead to a brighter, more acidic brew, while harder water can mellow out acidity. Experimenting with water choices can be an intriguing way to fine-tune your coffee's taste.
How Do You Reduce Your Coffee’s Acidity?
Now that you know what affects your brew’s acidity, let’s talk about how you can reduce that sourness and raise the pH a little bit.
- Add milk: Who doesn’t love turning their espresso into a cappuccino, or a cold brew coffee with oat milk? Milk is less acidic than coffee and will help reduce overall acidity.
- Pick dry-processed coffee varieties grown at lower altitudes.
- Try a darker roast: The longer (and hotter) the roasting process goes, the more that certain acids are broken down. This creates a smoother, less sour cup of joe.
- Opt for a cold brew: The colder extraction temperatures result in a less acidic coffee. Switching from drinking a pour-over to a cold brew coffee will give you the biggest noticeable difference in acidity levels.
- Add eggshells: I don’t personally recommend this, but legend has it that eggshells help reduce acidity. It makes sense according to chemistry. Eggshells are alkaline, so they’ll help neutralize any acid. Many people swear that it helps their stomach issues. That being said, I don’t want eggshells anywhere near my morning mug for health and taste reasons.
What Type of Coffee Beans Are the Least Acidic?
If you’re searching for some low acid coffee beans, we have you covered.
Brazil and Indonesia are two countries famous for producing low-acid coffee. I should know… I used to work as a specialty coffee roaster in Belo Horizonte, Brazil.
My advice? Stick to Central and South American beans, and stay away from the high acidity and floral profile of African beans (as delicious as they are).
Avoid light roasts, and opt for medium roast or dark roast coffee instead.
While Robusta has less acidity than Arabica beans, I recommend you always drink Arabica.
Why?
If you are looking for low-acid coffee, it’s probably because you don’t want an upset stomach or acid reflux. Robusta has about double the amount of caffeine as Arabica, which will negatively affect your stomach much more than the slightly higher acidity of Arabica. Plus, dark roast Robustas have a higher acetic acid concentration.
What Are the Health Impacts of Acidic Coffee?
From digestive concerns to the well-being of your pearly whites, understanding these health impacts will help you make informed choices about your daily coffee consumption.
Acid Reflux, Irritable Bowel Syndrome, and Gastric Ulcers
Coffee's acidity can be a double-edged sword for some individuals. While the tangy notes add to its appeal, they can also trigger issues like acid reflux and worsen symptoms of irritable bowel syndrome (IBS).
The high acid content may irritate the esophagus and stomach lining, leading to discomfort and potentially worse… gastric ulcers!
It's crucial for those prone to these concerns to moderate their coffee intake or opt for low-acid coffee options.
Coffee Acidity Impact on Teeth
While coffee aficionados appreciate the zesty flavors, the acidity in coffee can pose challenges to dental health as well.
Acidic beverages may contribute to enamel erosion over time, making teeth more susceptible to staining and decay. To mitigate this, consider sipping water alongside your coffee to help neutralize acids and practice good oral hygiene.
Note that enamel erosion occurs at pH levels below 5.5 (17)(18). This issue can be circumvented since there are many coffee drinks above this pH value.
You know… brush your teeth at least twice a day, and don’t forget to floss. But don’t brush just after drinking coffee because the brew may have softened your enamel (temporarily).
Related Reads:
Frequently Asked Questions
Is coffee more acidic than tea?
Coffee is generally more acidic than tea. Coffee's natural acids, like chlorogenic acid, contribute to its tangy taste, whereas tea's tannins create a different flavor profile. However, the exact acidity can vary depending on the coffee or tea type and preparation.
Does cold brew reduce acidity in coffee?
Yes, cold brew coffee tends to be less acidic than hot-brewed coffee. The cold brewing process extracts fewer acidic compounds, resulting in a smoother and milder taste. This makes it a preferable choice for those looking to reduce acidity while drinking coffee.
Is there a relationship between caffeine and coffee acidity?
Caffeine and acidity are somewhat related. Coffee's caffeine content can contribute to its perceived acidity. However, it's the natural acids, like chlorogenic acids, that primarily influence the coffee's tangy taste. Reducing caffeine doesn't necessarily decrease acidity, as decaf coffee can still be acidic.
Does milk neutralize acid in coffee?
Milk can partially neutralize the acidity in coffee. It works as a buffer, reducing the perception of acidity by raising the pH level relative to black coffee. The fats and proteins in milk may further mellow the flavor. However, milk doesn't eliminate all the acidity, and your coffee drink will still have a pH of less than 7.
Is decaf coffee less acidic?
Decaffeinated coffee can be slightly less acidic than regular coffee, but it still retains some acidity. The decaffeination process often removes some acidic compounds, but factors like bean variety and roast level also affect acidity. It's generally a milder option for those seeking reduced acidity for stomach issues. Caffeine can play a big part in stomach aches and acid reflux.
Does letting coffee sit make it more acidic?
Allowing coffee to sit does make it more acidic, as well as change its taste. As coffee cools, quinic acid is produced. This can lend a somewhat bitter, astringent quality to coffee. There’s a reason that reheating the coffee you left out for hours never tastes good.
Bottom Line
There you have it! Now you know all about what affects the pH of your beloved coffee.
Despite its reputation for acidity, the pH of coffee is around 5-6 and less acidic than you might think. Still, if you want to lower the acidity even further, you are now equipped with the right tools.
Understanding how factors like variety, origin, grind size, and roast level influence coffee's tanginess empowers you to adjust your brew accordingly and dial in the pH of coffee exactly how you want it.
Happy brewing!
