Is Coffee Acidic? pH Levels, Acids Explained and How to Reduce Acidity

Yes, coffee is acidic. But that is not the whole story. Coffee acidity is one of the most misunderstood topics in the coffee world. The acidity that makes a specialty Ethiopian pour-over taste bright and fruity is completely different from the acidity that gives you heartburn after a bad cup of office coffee.

This guide explains what coffee acidity actually is, what the pH of coffee means, which acids are responsible for flavour versus discomfort, and exactly how to brew a smoother, lower-acid cup if you need one.

What Is Acidity in Coffee?

In coffee tasting, acidity is a positive quality. It refers to the bright, lively, crisp sensation you get at the front and sides of your tongue when you sip a well-made coffee. It is what makes a light roast Ethiopian coffee taste like blueberries, or a Colombian pour-over taste refreshingly clean and sweet.

Acidity is one of the five core characteristics used to evaluate coffee quality, alongside body, aroma, sweetness, and aftertaste. A coffee with no acidity at all tastes flat and dull. Too much acidity, or the wrong kind, can taste sour or cause digestive discomfort.

The key distinction is between flavour acidity (desirable, contributes to taste complexity) and digestive acidity (the compounds that can irritate the stomach lining). These are not the same thing, and understanding the difference helps you make better brewing decisions.

The pH of Coffee

The pH scale runs from 0 (most acidic) to 14 (most alkaline), with 7 being neutral. Coffee typically falls between pH 4.5 and 6, making it mildly acidic, similar to tomatoes and orange juice.

Dark roast coffee is less acidic than light roast because the roasting process breaks down many of the acidic compounds. Cold brew is the least acidic of all common coffee preparations, with up to 60% less acidity than hot-brewed coffee.

The Main Acids in Coffee and What They Do

Coffee contains around 850 chemical compounds, and several of them are acids. Not all are equal in their effect on flavour or digestion.

Chlorogenic acid: The most abundant acid in coffee. It contributes to bitterness and body, and has antioxidant properties. It breaks down during roasting, which is why dark roasts taste less acidic.

Citric acid: Gives coffee a bright, citrusy quality. Common in light roast Ethiopian and Kenyan coffees. Desirable in small amounts, sour in excess.

Malic acid: Found in apples and stone fruit. Contributes a smooth, sweet-tart quality to the cup. Common in Colombian and Guatemalan coffees.

Phosphoric acid: Makes coffee taste sweeter and more complex. Found in high-altitude Kenyan coffees. A positive flavour acid.

Acetic acid: The same acid found in vinegar. In small amounts it adds brightness, but in excess (from over-fermentation or poor processing) it makes coffee taste sour and unpleasant.

Quinic acid: The problematic one. It develops when coffee is left on heat for too long or sits stale. It is harsh, bitter, and the main cause of the stomach discomfort people associate with bad coffee. Avoid it by never leaving coffee on a burner and always brewing fresh.

How to Reduce Coffee Acidity

Choose a darker roast: Roasting breaks down acidic compounds. A medium-dark or dark roast will have noticeably lower acidity than a light roast. If you are sensitive to acidity, this is the easiest first step.

Buy Arabica beans: Arabica beans are naturally lower in harsh acids than Robusta. Specialty Arabica, roasted fresh, will always produce a smoother, more balanced cup than commodity-grade coffee.

Try a different origin: Some origins are naturally lower in acidity. Brazilian and Sumatran coffees tend to be earthy and low-acid. Kenyan and Ethiopian coffees are naturally higher in bright, fruity acids. If acidity is a concern, start with a Brazilian or Colombian medium roast.

Add milk: Milk neutralises some of the acids in coffee and softens the overall flavour. A latte or flat white will always taste less acidic than a black coffee. Note that plant-based milks vary, and some (like almond milk) can curdle in very acidic light roast coffees. Oat milk is the most stable alternative. For a full comparison, see: Best Milk Alternatives for Lattes: Oat, Almond and Macadamia Compared.

Use coarser grind and lower temperature: Finer grinds and hotter water extract more acids. A slightly coarser grind and water at 90 degrees Celsius rather than 96 will produce a less acidic cup without sacrificing flavour.

Add a pinch of salt: A small amount of salt added to your grounds before brewing suppresses bitterness and perceived acidity. It works with any brew method and makes a noticeable difference.

Try eggshells: Eggshells are alkaline and can neutralise some of the natural acids in coffee. Rinse, crush, and add to your grounds before brewing. It sounds unusual but it is a well-known low-tech hack for reducing acidity.

Best Low-Acid Brewing Methods

Cold brew: The most effective method for reducing acidity. Steeping ground coffee in cold water for 18-24 hours produces a concentrate with up to 60% less acidity than hot-brewed coffee. The cold water simply does not extract the acidic compounds the way hot water does. See our full guide: Cold Brew Coffee: Everything You Need to Know.

French press: The metal filter retains more of the coffee's natural oils, which buffer acidity and add body. A well-made French press with a medium-dark roast is a good low-acid option. See: How to Make the Perfect French Press Coffee.

Moka pot: Produces a bold, low-acid espresso-style brew. The pressurised extraction at lower temperatures than espresso machines tends to produce a less acidic result.

Avoid drip coffee left on a burner: This is the single biggest cause of harsh, stomach-upsetting coffee. Quinic acid builds up rapidly in coffee left on heat. Always decant into a thermal carafe immediately after brewing.

Frequently Asked Questions

What is the pH of coffee?

Coffee typically has a pH between 4.5 and 6, making it mildly acidic. Light roasts sit closer to 4.5-5.0, medium roasts around 5.0-5.5, dark roasts around 5.5-6.0, and cold brew is the least acidic at 5.8-6.3.

Is coffee more acidic than orange juice?

No. Orange juice has a pH of around 3.3-4.2, making it significantly more acidic than coffee. Coffee at pH 4.5-6 is considerably milder in acidity than most fruit juices.

Does dark roast coffee have less acid than light roast?

Yes. The roasting process breaks down many of the acidic compounds in coffee. Dark roast coffee is measurably less acidic than light roast. If you are sensitive to acidity, a medium-dark or dark roast is a good starting point.

Is cold brew less acidic than hot coffee?

Yes, significantly. Cold brew has up to 60% less acidity than hot-brewed coffee because cold water does not extract the acidic compounds that hot water does. It is the best option for people with acid reflux or sensitive stomachs.

Why does coffee give me acid reflux?

Several factors can contribute: stale coffee (high in quinic acid), very light roasts (high in chlorogenic and citric acids), coffee left on a burner, or simply individual sensitivity. Switching to a medium-dark roast, cold brew, or adding milk can significantly reduce the problem.

Does adding milk reduce coffee acidity?

Yes. Milk is slightly alkaline and neutralises some of the acids in coffee. It also coats the stomach lining, which reduces irritation. A latte or flat white will always be gentler on the stomach than a black coffee of the same roast.