How to reduce acidity in coffee

As a barista who loves coffee, chocolate, wine, and most other acidic delicacies, I get acid reflux and heartburn almost daily. I finally took the time to scour the internet for a way to save my esophagus. For the 15 million Americans who also experience heartburn daily, here’s what I’ve learned about the science behind digesting coffee and how to reduce its acidity. 

A refresher on acid-base chemistry

First, a quick chemistry lesson in acids and bases. Acidity is measured on the pH scale where lower pH denotes higher acidity;  0  is most acidic, 7 is neutral and 14 is most basic. The more acidic the substance, the more hydrogen ions in its solution. Hydrogen ions cause all sorts of reactions in the human body, some of which can lead to stomach discomfort. 

The pH of coffee is about 5, which means it’s acidic. Many other beverages like juices and sodas are significantly more acidic than coffee, but the caffeine in coffee increases acid levels in your stomach further because it’s a natural stimulant that increases contractions in your digestive tract. 

Types of acids in coffee

Roasted coffee contains at least 38 different organic acids: citric, malic, and quinic acids are the most prominent in green coffee. These acids give coffee its signature smell and taste, but some acids like quinic acid continue to be released as brewed coffee deteriorates, such as when it’s left on a coffee-maker hotplate. The result is an unpleasantly bitter and burned-tasting coffee. Coffee also contains chlorogenic acids (powerful antioxidants), but the greater the roasting duration and temperature, the less chlorogenic acid is preserved. The same acid degradation during roasting occurs for most acids in coffee, which is why dark roasts are generally less acidic than light roasts. This brings us to the good news: you can reduce the amount of acid in your coffee by choosing lower-acid beans, brewing them differently, and prepping your stomach to digest your cup of coffee easier. 

Lower-acid coffee options 

• Dark roasts have a lower acid profile because they contain fewer compounds that cause the stomach to produce acid. Light roasts, on the other hand, retain a high amount of coffee's natural acidity. In fact, study participants who drank dark roast blends experienced lower levels of gastric acid secretion than those who drank a medium roast. 
• Decaf coffee contains almost zero caffeine. As noted previously, eliminating the caffeine will prevent your stomach from producing excess acid. 
• Many low-acid coffee varieties exist naturally! The growing conditions of coffee play a major role in the acidity of the brew. Soil mineral content has a large impact in this regard; the less acidic the soil, the less acidity transferred into the bean. This is true of some coffee from regions in Brazil and Indonesia. Low-elevation regions tend to produce beans with lower acidity, while high-elevation regions such as Peru, Ethiopia, and Guatemala tend to produce more acidic beans. 

Brewing methods for lower-acid coffee

• Cold brew is made by steeping coffee for 12 - 24 hours in cold or room-temperature water. This slow extraction combined with cooler temperature creates a less acidic brew. Brewing at cooler temperatures reduces how much acid is extracted because different compounds are extracted at different rates from coffee beans. The lack of heat during extraction also reduces the amount of oxidation (e.g. hydrogen ions) happening to compounds in the coffee grounds. Cold brew is one of the most effective ways to reduce acid in your coffee, as it can do so by 60%. Even though cold-brewing effectively lowers total coffee acidity, hot-brewed coffees have higher antioxidant activity (like chlorogenic acids).
• Espresso uses a shorter extraction time than other brewing methods, which reduces the amount of acids extracted from the beans. Also, cafes commonly use dark and medium roasts for espresso – we use Black Magic!
• Brewing coffee with a fine grind, such as for espresso or AeroPress, tends to result in lower acidity. In contrast, coffee ground coarser, for methods like a French press, yields fairly acidic coffee. 
• Paper filters can absorb more acids during brewing compared to metal filters in French presses and other devices with reusable filters. 
• Adding more water to your coffee is a surprisingly simple solution. Since water is neutral (pH 7), it is essentially an alkalizing agent that will lessen the relative prevalence of hydrogen ions. If you usually make your coffee really strong, try using a slightly weaker coffee-to-water ratio, such as 1:17 instead of 1:15. 

Methods to help your stomach digest coffee easier

• Don’t drink coffee on an empty stomach. 
• Limit your daily coffee intake to no more than 3 - 4 cups or 400 milligrams of caffeine.
• Stick to only alkaline milks like almond or soymilk. Dairy (pH 6.4 - 6.8), oat, and nut milks (besides almond) tend to be acidic. 
• Use low-pH types of sugar. For example, natural, unprocessed sugars tend to be slightly basic, but refined sugars are acidic. 
• Use alkalizing agents: Lastly, you could resort to taking an antacid beforehand, or even adding a tiny amount of baking soda (¼ of a teaspoon) to your coffee (fair warning: I have not and will not try this method!).

Written by 
Melina Devoney 
Barista, Coffee Captain, Blogger