Coffee is one of the world’s most popular beverages, with over 2 billion cups consumed every day. But there has been some debate around whether coffee is acidic or alkaline. This article will explore the pH of coffee and the compounds that contribute to its acidity or alkalinity. We’ll also look at how factors like brewing method and additives like cream and sugar impact the pH of your morning cup of joe. By the end, you’ll understand exactly where coffee falls on the pH scale and how its acidity affects your body.
What is pH?
Before we can determine if coffee is acidic or alkaline, we first need to understand what pH measures. pH stands for “potential hydrogen” and it is a scale used to measure the acidity or alkalinity of a solution.
The pH scale ranges from 0 to 14:
– 0 to 6 is acidic
– 7 is neutral
– 8 to 14 is alkaline
pH is measured based on the concentration of hydrogen ions (H+) and hydroxide ions (OH-) in a substance. Acids have more hydrogen ions, while bases have more hydroxide ions.
Pure water has a neutral pH of 7. Any reading below 7 indicates acidity due to excess hydrogen ions. Readings above 7 indicate alkalinity due to more hydroxide ions. The farther the number is from 7, the stronger the acidity or alkalinity.
Acidity and Alkalinity
Acidity and alkalinity refer to where a substance falls on the pH scale:
– Acids have a sour taste and a pH below 7. Common acids include vinegar, lemon juice, and soda.
– Bases have a bitter taste and a pH above 7. Common bases include baking soda and bleach.
The acidity or alkalinity of a food or drink can impact your teeth, digestion, and overall health. Generally, acidic foods are more damaging to tooth enamel while alkaline foods help neutralize stomach acid.
Now that we understand pH, acidity, and alkalinity, we can evaluate whether coffee is acidic or alkaline.
Is Coffee Acidic or Alkaline?
Coffee is acidic, with a pH ranging from 4.5-6 on the pH scale. This means it contains more hydrogen ions than hydroxide ions, giving it acidic properties.
The acids in coffee come from a few different sources:
Natural Acids in Coffee Beans
Coffee beans contain natural acids that give coffee its tangy, bright taste. The main acids found naturally in coffee are:
– Chlorogenic acid – a polyphenol antioxidant
– Citric acid – provides a fruity taste
– Malic acid – gives tart apple flavors
– Quinic acid – contributes to bitterness
These organic acids make up approximately 8% of roasted coffee beans by weight and are extracted into the coffee we drink.
Carbon Dioxide
When coffee beans are roasted, carbon dioxide is released. Some of this carbon dioxide dissolves into the water during brewing, forming carbonic acid.
Hydrolysis of Chlorogenic Acids
Additional acids are formed in coffee through the hydrolysis (splitting) of chlorogenic acids during the brewing process. This releases more quinic and caffeic acids.
So the natural organic acids in coffee beans, carbon dioxide, and hydrolysis reactions all contribute to the acidic nature of brewed coffee.
Factors that Affect Coffee’s pH
While coffee is inherently acidic, the exact pH can vary depending on certain factors:
Roast Level
The degree of roasting affects coffee’s pH. Light roasts are less acidic with a pH of 5.2-5.3. As roasting increases, the pH decreases, making it more acidic. Dark roasts have a lower pH around 5.0.
Longer roasting leads to less chlorogenic acid and more quinic and caffeic acids as the chlorogenic acid breaks down.
Brewing Method
Brewing method impacts acid extraction from the beans. In general:
– Drip coffee is less acidic with a pH of 5.2-5.7
– French press and espresso are more acidic with a pH of 4.5-5.0
Percolation methods like drip brewing have less contact time between water and grounds, extracting fewer acids. High pressure extraction like espresso has more contact time and extracts more acids.
Coffee-Water Ratio
The coffee to water brewing ratio also affects acidity. More concentrated coffee with a higher coffee-water ratio is more acidic. Diluted coffee is less acidic.
Processing Method
How the raw coffee beans are processed after harvesting influences acidity. Wet-processed coffees tend to be less acidic with a pH of 5.2-5.3 vs 5.0-5.1 for dry-processed.
Origin and Coffee Variety
Where the coffee is grown impacts acidity due to differences in soil, altitude, climate, and bean variety. For example, some origins known for a bright, fruity acidity include:
– Kenyan – pH 5.1
– Colombian – pH 5.2
– Costa Rican – pH 5.2
Arabica beans also tend to be less acidic than Robusta varieties.
Additives
Adding cream, milk or sugar will raise coffee’s pH slightly toward neutral but not enough to make it alkaline. For example, adding 2 oz of half and half to 6 oz of black coffee raises the pH from 5 to 5.2. Sugars and proteins in dairy have a buffering effect against acids.
Acidity Differences in Coffee Types
To summarize the factors above, here is a comparison of the pH of different types of coffee drinks:
| Coffee Type | pH |
|---|---|
| Light roast drip coffee | 5.2 – 5.7 |
| Dark roast espresso | 4.5 – 5.0 |
| Cold brew | 5.7 – 6.1 |
| Black coffee with cream | 5.0 – 5.2 |
| Cappuccino | 5.0 – 5.2 |
As you can see, black coffee without additives consistently tests as acidic. Factors like brew method and roast level impact the acidity, but coffee remains on the acidic end of the pH scale. The addition of dairy or sugar causes a slight increase but not enough to make coffee alkaline.
Health Effects of Coffee’s Acidity
Now that we know coffee is acidic, let’s look at how its acidity impacts your health.
Dental Erosion
One downside to coffee’s acidity is it can erode tooth enamel over time. Acids in coffee remove minerals like calcium from tooth surfaces. A cup of black coffee (pH 5) is almost as acidic as lemon juice (pH 2) when it comes to effects on teeth.
Moderate coffee drinkers have 17% higher risk of dental erosion compared to those who drink little or no coffee. Heavy coffee consumption is linked to significantly higher dental erosion.
Tips to minimize the eroding effects on your teeth include:
– Drink coffee quickly instead of sipping over long periods. This limits exposure time.
– Rinse mouth with plain water after drinking coffee.
– Wait 30-60 minutes before brushing after coffee, as brushing right away can accelerate enamel loss.
– Drink through a straw placed towards the back of the mouth to bypass teeth.
– Use milk or cream as buffers.
Heartburn and GERD
The acidity in coffee can aggravate heartburn and gastroesophageal reflux disease (GERD) for some people. Heartburn is felt as burning pain behind the breastbone, caused by stomach acid rising into the esophagus.
Coffee’s relaxation effect on the lower esophageal sphincter muscle allows stomach acid to reflux into the esophagus more readily. Compounds in coffee also stimulate acid production in the stomach.
Those with ulcers, gastritis or other gastrointestinal disorders may also react poorly to coffee’s acidity.
Tips for reducing heartburn and GERD symptoms include:
– Avoid coffee on an empty stomach
– Switch to low-acid coffees
– Use milk or cream as buffers
– Drink in moderation or avoid altogether if very sensitive
Digestion
The acidity in coffee has some beneficial effects on digestion. Chlorogenic acid and other antioxidants in coffee help stimulate the production of gastric juices. Coffee’s acids also aid digestion by enhancing the activity of the gastrointestinal tract.
However, coffee’s acids can cause discomfort when consumed in excess, especially in those already prone to digestive issues. Those with digestive conditions like IBS may be sensitive to the stimulatory effects of acids in coffee.
As with heartburn, drinking coffee with food and using dairy buffers can help minimize adverse digestive effects of acidity. Moderating intake is key if you find coffee disagrees with your stomach.
Bone and Calcium Loss
High amounts of caffeine in coffee can interfere with calcium absorption and contribute to calcium loss via urine output. This effect is worsened if drinking coffee on an empty stomach.
Since a low calcium intake can contribute to reduced bone mineral density and osteoporosis over time, coffee lovers should ensure adequate calcium consumption from food sources like dairy, leafy greens, tofu and calcium-fortified foods.
Positive Antioxidant Effects
Despite the downsides of its acidity, coffee boasts many antioxidants that benefit health, including:
– Chlorogenic acid – anti-inflammatory, lower blood pressure
– Caffeic acid – anti-inflammatory, anticarcinogenic
– Melanoidins – antioxidant, anti-inflammatory
These antioxidants reduce inflammation, protect cells from damage, improve cholesterol profiles and blood sugar regulation.
The beneficial antioxidants far outweigh coffee’s acidity given moderate, regular consumption. Those with sensitive digestive systems can use methods to minimize acid effects and still reap coffee’s perks.
Is Decaf Coffee Less Acidic?
Since caffeic and chlorogenic acids give coffee much of its acidity, you may wonder if decaffeinated coffee is less acidic.
Surprisingly, decaf coffee has similar acidity levels to regular coffee. Decaffeination only removes caffeine, leaving the other acids intact.
Decaf coffee is around 99.7% caffeine-free, but contains all the other coffee compounds like chlorogenic acids. So while it has less caffeine, its pH is nearly identical to regular brewed coffee.
Switching to decaf may help those sensitive to caffeine’s digestive effects, but not coffee’s acidity specifically.
Tips for Lower Acid Coffee
If you enjoy coffee but struggle with the acidity, these simple tips can help reduce irritation:
– Choose darker roasts, as they are less acidic.
– Brew coffee using methods like drip or pour-over that extract fewer acids.
– Use a 1:15 coffee-water ratio or dilute after brewing with more hot water.
– Add milk, cream or non-dairy milk – proteins help neutralize acids.
– Drink coffee with or after a meal to reduce acidity on an empty stomach.
– Avoid drinking coffee 2-3 hours before bed. Acids can reflux as you lie down.
– Some people tolerate cold brew coffee better due to lower acidity.
– Try coffee alternatives like chicory, dandelion tea or golden milk lattes.
You can also buy low-acid coffee that has been chemically or naturally treated to reduce acids:
– TechnoRoasting uses CO2 buffers to neutralize acids
– Puroast Coffee is slow-roasted to reduce acids
– Lennon Coffee Co. sprouts green coffee to mellow acidity
With some adjustments to your brewing routine or choice of beans, coffee lovers can continue enjoying their daily cup of coffee. Be sure to consume coffee in moderation, about 3-4 cups spread throughout the day maximum.
The Bottom Line
Coffee is acidic, with a pH of around 5 for black coffee. The organic acids occur naturally in the coffee beans and are extracted during brewing. Additional acids form during roasting and brewing processes.
Many factors like brew method, roast level and additives impact the final acidity. But coffee remains on the acidic end of the pH scale regardless of adjustments.
While acidic, coffee provides many health benefits due to its antioxidant content. But its acidity can cause dental erosion, heartburn, and digestive upset in excess. Using buffering additives like milk and drinking in moderation can help minimize negative effects while still enjoying your morning cup of joe.