"When it comes to America’s favorite morning drink, there are countless ways to take your coffee. Whether you take it with cream or sugar, iced or hot, many people also take it with an upset stomach, diarrhea, or heartburn. While coffee has many health benefits, it can also cause digestive symptoms. Especially if you’re one of the 60 million Americans with acid reflux, the best reason to get out of bed in the morning can also cause heartburn, indigestion, bloating, or other digestive upset. The culprit? The biggest factor besides caffeine is that coffee is highly acidic. But what exactly is coffee acidity, and how does it affect your health (whether or not you have acid-related symptoms)? Is there a way to decrease the acidity to enjoy symptom-free coffee? I asked experts to spill the (coffee) beans.
Dr. Daryl Gioffre
Author of the best-selling books Get Off Your Acid and Get Off Your Sugar, Dr. Daryl Gioffre is a highly sought-after gut health and inflammation specialist with over two decades of experience in the field.
Katie Sanger, MS, RDN
Katie Sanger is a registered dietitian at Well Theory who specializes in functional and integrative health, focusing on the root cause of health issues with the aim of building lasting and sustainable health.
What is Coffee Acidity?
In general, acidity is determined using the pH scale, which denotes how basic or acidic a water-based solution is (the scale ranges from zero to 14, with zero being the most acidic). The brewing process releases acid from coffee beans, and the average pH value of coffee is 4.85-5.10 (which is considered higher on the acidity scale). However, other factors like roasting duration and temperature, the brewing method, and the size of the coffee grounds can affect the acidity of coffee. Research shows that coffee contains a variety of acids, some that are responsible for its delicious flavor and others that cause digestive upset. “Coffee is made up of over 800 different volatile compounds and acids,” explained Dr. Daryl Gioffre, a nutritionist, gut health expert, and author of the best-selling book Get Off Your Acid. “While some of these acids are beneficial and will add to your coffee’s flavor, most will drive up inflammation in your body, contribute to acid reflux, and prevent your body from losing weight.”
Why Does Acidity Cause Digestive Symptoms?
Registered dietician Katie Sanger, MS, RDN, explains why coffee acidity can exacerbate acid reflux, heartburn, or other gastrointestinal issues in sensitive individuals: “The high levels of chlorogenic acids in coffee can increase stomach acidity, leading to discomfort in those with conditions like GERD (gastroesophageal reflux disease) or ulcers,” she said. The acidity in coffee stimulates the production of gastric acid, which can increase digestion for some (why many people feel coffee helps them stay “regular”) and lead to bloating, indigestion, constipation, or diarrhea for others. Dr. Gioffre added that the reactive acids in coffee can be highly irritating to your gut microbiome, so much so that they can leak holes through your gut lining (AKA leaky gut).
What Other Ways Does Coffee Acidity Affect Health?
Even if you don’t get an upset stomach or acid reflux after drinking coffee, highly acidic coffee can still cause health issues and negatively affect the body.
Increased risk of cavities and gum disease
If you drink a lot of highly acid coffee, you can weaken enamel (the protective, outer covering of your teeth) and create an environment in your mouth that’s more prone to bacteria growth. “The acidity in coffee can contribute to enamel erosion over time, especially if consumed frequently without adequate dental hygiene,” Sanger said. This can lead to staining of the teeth and an increased risk of cavities, tooth sensitivity, tooth decay, and even gum disease.
Lower bone density
The acidity of coffee may interfere with how the body absorbs, metabolizes, and eliminates calcium. In other words, even if you have proper calcium intake (an essential mineral for bone health), the body may not be able to fully absorb it. “Some studies suggest that excessive consumption of acidic coffee may affect calcium absorption, potentially impacting bone density over time,” Sanger said. Because high levels of caffeine consumption (more than three to four 8-ounce cups of coffee) prevent calcium absorption, the important mineral flushes out of your system and is eliminated when you urinate. “However, this effect is generally mild and more of a concern for individuals with already low calcium intake,” Sanger continued. It’s also important to stress that studies only show this correlated with high coffee intake (3-4 cups a day).
Less nutrient absorption
In addition to calcium, the acidity in coffee can interfere with nutrient absorption of essential minerals such as magnesium, B vitamins, and iron. Based on studies in the American Journal of Clinical Nutrition and the British Journal of Nutrition, drinking coffee with a meal is associated with a 39–90 percent reduction in iron absorption, and the stronger the coffee, the less iron absorbed. “Consuming coffee close to meal times may inhibit the absorption of non-heme iron (found in plant-based foods), which could be a concern for individuals at risk of anemia,” Sanger confirmed.
Tips to Reduce Acidity in Coffee
Choose low-acid coffee beans
The region where coffee is grown affects its acidity. Dr. Gioffre said that coffees from higher altitudes tend to have higher acidity levels due to a slower ripening process, so buying beans that are grown at lower elevations and in regions known for producing less acidic coffee, like Brazil or Sumatra, are best for lowering the acid content. When you’re shopping for coffee, look for beans from Brazil, Sumatra, Vietnam, or Nicaragua, as well as Robusta beans (over Arabica beans), espresso beans, or chicory blends, as they are less acidic to your body.
Opt for a dark roast
The variety of roast can not only affect the taste of coffee but also its acidity levels. A study published in Molecular Nutrition & Food Research found that participants who drank a dark roast blend showed lower levels of gastric acid secretion than those who drank a medium roast. “Lightly roasted coffee tends to retain more of its natural acidity, while darker roasts tend to lose some of that acidity and develop more bitter or roasted flavors,” Dr. Gioffre explained. In other words, the darker the roast, the lower the acid profile. Dr. Gioffre recommended opting for a dark roast instead of a medium or light roast and not letting your coffee sit around for a long time (the longer it sits, the more acidic it becomes).
Brew for longer and at a lower temperature
“The brewing method and extraction time can also influence the acidity in the final cup, and the finer the grind size increases acidity, as it exposes more surface area of the beans,” Dr. Gioffre explained. Since acids are some of the first compounds to be released while coffee is brewed, the shorter the brew time, the higher the concentration of acidity. So, to lessen your coffee’s acidity, try brewing it for longer (i.e., using a French press) at a lower temperature (think: cold brew coffee). And because coarser coffee grinds contain large coffee particles and slow down the extraction rate, using coarser grounds at a lower temperature will lessen the acidity of your coffee.
Supplement with acid reducers
You can also be mindful of what to add to any cup of coffee to either lower its acidity or help your body handle the acidity. Dr. Gioffre suggested adding 1 tablespoon of coconut oil, a dash of cinnamon, and/or a pinch of Himalayan pink salt or baking soda to help counteract some of the acidity in coffee. Plant-based milks, like almond or soy, are alkaline in nature, which can aid in balancing the pH of your coffee, giving you a much less acidic cup of coffee. You can also consider using a store-bought acid reducer with alkalizing properties that works to neutralize acidity in your next pot or cup of coffee—just look for options made from natural ingredients.
Katherine Chang, Wellness Staff Writer
Katherine Chang is The Everygirl’s Wellness Staff Writer with over five years of experience in the health and wellness space. She navigates the latest wellness topics and trends through studies, articles, and is always first in line to try them firsthand.