Yes, like almost all of humankind’s favorite beverages, coffee is acidic. But, it actually contains less acid than many of the other drinks you consume on a daily basis. So, if you think coffee’s acid content is upsetting your stomach, it’s time to rethink. (We’re not saying that coffee isn’t upsetting your digestive system — we’re just saying it’s probably not the acid. More on this below.)
If, on the other hand, you’re asking about acidity because your cup of coffee tastes sour, then your caffeine quagmire is likely caused by acidity as a tasting note, rather than by the actual level of acid in your coffee.
We’ll explain the difference between coffee’s actual acid content and its perceived acidity. Plus, we’ll share the steps you can take to troubleshoot digestive issues and neutralize the sour taste in your morning brew.
Acid is a chemical compound that we can measure in a lab, which means we can determine the amount of acid in coffee (or any water-based solution) in concrete terms. We can put a number on it.
Acidity, on the other hand, is the way we experience acid in our food. Acid is one of the building blocks of flavor, according to the best-selling cookbook and accompanying documentary “Salt, Fat, Acid, Heat” by Samin Nosrat. So, the acidity of coffee helps create its flavor profile.
Acidity is our perception of acid, and perception is a lot harder to measure than the actual amount of acid — but that doesn’t stop people from trying. Sommeliers make their living by commenting on the flavor profile of wine, and part of that process involves determining whether the wine has balanced acidity.
When the acidity is balanced, the wine is “bright,” but when the acidity isn’t balanced, the wine is “sour.” Bright is good — sour is bad. If a wine doesn’t have enough acidity, it’s sometimes described as “heavy.” Acidity helps to lift heavy flavors and make them feel lighter and more complex. And, these terms aren’t exclusive to the wine industry. There are professionals called Q Graders who perform these same tasting rituals on coffee.
And yet, when measured in a lab, the actual amount of acid in a “bright” coffee might be exactly the same as the amount of acid in a “sour” coffee. So, what’s going on here? Let’s start in the lab.
We’ve already determined that coffee is acidic, and we determined this using the pH scale. The pH scale is a simple measuring system, so you don’t need a PhD in Chemistry to understand how it works.
This scale ranges from 0-14. Any solution that measures from 0-6 is acidic. Seven is neutral — that’s the pH level of water. And any solution that measures from 8-14 is alkaline or basic (and we don’t mean basic like a Pumpkin Spice Latte). So, the lower the number, the more acidic it is. One is more acidic than two, which is more acidic than three, and so on.
The pH of coffee ranges from 4.85 to 5.13, according to a study published in Scientific Reports. So, coffee is an acidic solution, but because it’s a higher number on the acidic side of the pH scale, coffee actually contains less acid than you might expect compared to some of the other beverages you love.
Here’s a look at how the pH level of coffee compares:
- Coffee: 4.85-5.13
- Black Tea: 4.5-5.9
- Orange Juice: 3.5
- Apple Juice: 3.48-3.69
- Beer: 4.1-4.5
- Wine: 2.9-4.2
- Soda: 2.5-3.5
So, if drinking coffee is upsetting your digestive system but drinking orange juice isn’t, the pH level may not be the problem.
How Does Coffee’s pH Level Affect Your GI Tract?
To decide if this is the problem, try this experiment: Drink your morning coffee as usual. Take note of the symptoms you experience, when they start, and how long they last. Once you have a good idea of the effects of coffee on your body, repeat this process with another acidic beverage, like orange juice, wine, beer, or caffeine-free soda. (Make sure to do this at a time of day when you haven’t recently had coffee and all of your coffee-related symptoms have passed.)
Do you experience the same symptoms from the other acidic beverage? If so, then acid is probably the culprit. Try switching to a low-acid diet and drinking low-acid coffee (which has some of the acid removed during processing) to get you your caffeine fix.
Other Chemicals in Coffee That Can Cause GI Issues
If other acidic beverages don’t cause the same symptoms, then the acid content in your coffee probably isn’t to blame for your GI symptoms. Here are the more likely culprits:
- Caffeine: Some scientific research has found that caffeine can upset the GI tract, but a meta-analysis found the evidence inconclusive. To decide for yourself, try switching to decaf or half-caff coffee for a month to see if your symptoms improve.
- Coffee grounds: If your brewing method leaves grinds in your drink, these particles could be upsetting your stomach. Try switching from a wire filter or filter-less method, like the French press, to a drip method that uses a paper filter.
- Dairy: High-fat foods can cause acid reflux, so the creamer in your coffee may be the true culprit behind your symptoms. Dairy is also one of the most common food allergies and can cause a variety of GI issues. Try switching to a dairy-free creamer or drinking your coffee black to see if your symptoms improve.
- Soy: Soy is another common allergen, so if you’re using a soy-based creamer, it could be causing your upset stomach. Try switching to black coffee or a soy-free creamer for a month to see if it helps.
We hope you enjoyed your foray into the science lab and found a solution for any GI problems your coffee might be causing. Now, let’s leave the lab behind and join the rest of the world’s coffee drinkers in their coffee shops.
When you sit down in your favorite coffee shop to savor a cup of coffee, the types of acid in the coffee beans, plus the roasting process, brewing method, brewing temperature, and brewing time will all affect its flavor profile.
The most common type of acid in coffee is chlorogenic acid. This acid is an antioxidant that’s often credited for coffee’s many health benefits. It converts to quinic acid (the same stuff that’s in tonic water) as the coffee brews.
Too much quinic acid in your coffee can make it taste bitter or sour. And longer, hotter brewing times tend to produce more quinic acid. That’s part of the reason that cold brew coffee has a lower acidity profile than hot brewed coffee — even though their pH levels are about the same.
The other types of acid in coffee are present in much smaller amounts, but they give different coffees their different flavors. Coffee beans that contain citric acid will have more citrusy flavor profiles. Beans that contain malic acid will have notes of apples. And if coffee has too much of one type of acid, it can make the acidity imbalanced and lead to a sour flavor.
How to Change the Acidity Profile in Your Coffee
You can play with your coffee’s flavor profile by bringing out more or less of its acidity. Use these tips to choose coffee with more balanced flavor:
- Choose medium roast coffee over light roast: Lighter roasts maintain more acidity, while darker roasts bring out a chemical that suppresses the acidic flavor. However, a very dark roast can taste burnt and bitter. For the most balanced flavor profile, choose a medium roast coffee.
- Buy Arabica beans over robusta beans: These are the two most common types of coffee beans, with arabica beans being the more expensive of the two. Arabica beans tend to have a more balanced acidity profile with a sweeter and less sour taste.
- Look for beans grown at higher altitudes: High altitudes produce more complexly flavored beans, so look for beans grown at high elevation to get more balanced acidity in your cup.
- Consider the region: Some growing regions, like Kenya, produce coffees with higher acidity, while Brazilian coffee, Costa Rican coffee, and Bali coffee tend to have lower acidity.
- Read the flavor profile: For lower acidity, avoid beans that list citrus, berries, and other fruit notes in their flavor profile. Select beans with caramel, chocolate, and nutty notes instead.
- Choose regular coffee over espresso: Espresso has higher acidity than regular or drip coffee because it’s extracted at a much higher temperature.
- Opt for a medium or coarse grind: Brewing fine ground coffee will extract more of the acidic flavor profile. For less acidity, use a medium or coarse grind.
- Don’t leave your coffee on a hot plate: Keeping your coffee on the heat for too long brings out more quinic acid, which makes the coffee taste bitter or sour. Take your coffee carafe off the hot plate as soon as it’s finished brewing, and keep it warm with an insulated thermos instead.
Coffee is acidic, but so are most of the tasty things in this world — including juice, wine, beer, and soda. In fact, coffee actually has a lower pH level than each of those beverages. So, if you’re able to drink juice or soda without upsetting your stomach, then the acid in coffee won’t be a problem either. (However, something else in coffee, like caffeine or dairy, could still be to blame for your GI upset.)
Acid is an essential component of flavor, and the different types of acid in coffee create different flavor profiles — from bright and fruity to rich and nutty. You can bring out or tone down the acidity in your coffee by choosing beans with a different roast, origin, or grind. But whatever you do, don’t leave your coffee boiling on a hot plate all day. This will bring out the sour-tasting quinic acid. And, your morning beverage deserves better!
To learn more about everyone’s favorite brew, join us at Cup & Bean where we pour over every detail in every cup.