Coffee is one of the most popular beverages in the world, not to mention coffee culture, present in all corners of the earth. Although depending on the location, different things come into mind when you think of coffee (for instance, in the Western world, most people would think of Starbucks), there’s one thing no one can deny – its impact on the world.
You can see so many companies that offer personalized coffee accessories, and you can even find websites that are created only to show off some of the best design ideas for cup sleeves.
Its success is based on the fantastic properties and a deep, sour flavor. Unfortunately, every coin has two sides, and coffee can often cause many problems, like stomach aches. In general, they are attributed to the acidity of coffee. But is it really it? And what does acidity even mean? Can you do anything to change the pH of your coffee? You will find the answers to these questions and more below.
What Is pH?
All substances are either alkaline or acidic, and this is measured on the pH scale. The scale runs from 0 to 14, with a neutral value of 7 (e.g., water). Anything with a pH less than seven is considered acidic, while with more than 7, alkaline.
A substance with a pH value of 6 is considered mildly acidic; something with a pH value of 0 is highly acidic. A value of 8 on the pH scale indicates a mild alkaline substance and a value of 14, a strong alkaline. With an average pH ranging between 4.8 to 5.10, coffee is considered slightly acidic – its acidity depends on different factors. For comparison, orange juice has a pH value of 3, tomato juice of 4, and milk of 6.
Probably the first thing you think about when you hear the word “acid” is a sour food that will be hard on your stomach. It’s safe to say that acidity is a term that is not usually desired in the food industry.
However, when it comes to coffee, it’s a desirable trait and a critical taste component. Actually, when coffee professionals talk about “acidity,” they refer to the presence of certain acids that influence the taste of the coffee.
Coffee beans contain at least 850 components that contribute to the unique taste, and among them, you can find seven major acids:
- Chlorogenic acid – during roasting, chlorogenic acid slowly decomposes and forms quinic acid.
- Quinic acid – is associated with an increase in the perceived acidity of coffee.
- Citric acid – best known because of lemons. It exists in high levels of green coffee, and it can be reduced while roasting.
- Acetic acid – found in vinegar, and it is created during processing and roasting. It contributes to a rounded, clean tasting cup, as it can create significant complexity.
- Malic acid – most commonly found in apples and pears, so that you can recognize coffee with a higher level by this fruity, punchy taste.
- Phosphoric acid – introduced to the plant during fertilization. Known to add a beautiful blackcurrant note to Kenyan coffees, it’s lighter and has a more sparkling acidity.
The one acid you can’t feel directly in the taste is lactic acid. It is responsible for making your coffee more creamy, and it deepens the body.
So, where does acidity come from?
It Starts With the Plant
Cellular respiration results in the formation of acids – this process can be affected by many environmental factors, like insolation or altitude. Shade-grown and high-altitude plants tend to have higher levels of organic acids, chlorogenic acids, caffeine, and sugar. Because of the lower sunshine levels, they are growing much slower, which allows more nutrients to be packed into the fruit.
There is also a big difference between various strains. For example, the Robusta coffee exhibits much higher levels of chlorogenic acids than Arabica. Chlorogenic acid imparts a bitter, vegetal taste, so particular coffee varietals play an essential part in the cup’s resulting flavor.
You can see the impact of processing when you compare dry, wet, or semi-washed beans. Washed coffee has the highest acidity level, as the fruits are first pulped and soaked, and it leaches content from coffee. Dry processed coffee leaves all fruits intact so that the sweetness is increased.
Coffee roasting both converts and breaks down acids, resulting in the formation of acids and influences their levels. For instance, malic and citric acids deplete during the roasting process, so the darker the coffee is, the more acids are broken down. However, some chlorogenic acids break down, and they create other acids, like quinic acid. Finally, when sucrose degrades during the roasting process, it forms acetic acid, which you would recognize as vinegar.
Brewing binds it all together. The number of acids extracted while brewing can affect the balance of acidity, the perceived strength/dilution of acidity, and the balance of acidity vs. sweetness. You can notice that the cooler the coffee is, the sourer it becomes.
The Flavor Profile
The sensory profile of a cup of coffee varies according to several factors like the type and blend of coffee beans, geographical source, roasting method, and method of preparation. On the Internet, you can find various maps and wheels of coffee flavors. The first one was made over 20 years ago by the Specialty Coffee Association of America (SCAA).
Sensory experts describe specific aroma and flavor profiles to differentiate various types of coffees and roasts. Aroma and taste are the most important factors determining coffee preference.
The more acidic coffee, the taste is sharper and more bright. Very acidic coffees have a complex flavor profile, and often you can feel flowery or fruity notes. The most significant factor that affects acidity is the altitude at which the plant grows. Coffees grown at higher altitudes tend to ripen more slowly, allowing more time for complex flavors to develop.
When people say that coffee is a cause of stomach problems, they probably mean reflux or heartburn. Generally, that is true, as coffee causes an increase in stomach acids. But is it really due to the pH of coffee?
According to research, the main factor for digestive issues caused by coffee is caffeine. Though caffeine is a powerful mental stimulant, it can increase the frequency of contractions throughout your digestive tract. Also, some research suggests that caffeine may increase stomach acid production, which could upset your stomach if it’s susceptible. Coffee indeed contains many acids, but they don’t play a significant role.
In some cases, the problems may be caused by additional substances like milk, sugar, sweeteners, or cream, which most people add to their coffees. For example, 65% of people can’t properly digest lactose which may trigger symptoms like bloating, stomach cramps, or diarrhea soon after consuming dairy.
If you are not sure why coffee is harmful to you, you can always do a test. Leaving out dairy is easy, as you can just give up on it, but what about caffeine? You can buy it in the form of pills or try a caffeinated energy drink. If you will feel bad, it means that you are oversensitive to it. So what now? The only remedy you can try is drinking low caffeine or decaf coffee for a while. It may prove to be more effective than looking for low acidic coffees, which may not be even that different in terms of pH.
Brewing is an important factor when it comes to acidity. Moreover, the technique and ingredients you use may influence the pH of coffee.
Coffee is 94-98% water, so the quality of it can make a big difference. You can divide water types into hard water and soft water. Hard water is rich in minerals in terms of magnesium and calcium, while soft water has low mineral content. According to Thomas Chandler, a top coffee roaster, molecular biologist, and chemist, carbonate is an “acid buffer”: the more carbonate in the water, the less acidic the brew. However, it is not the only compound buffer, and carbonate’s ability depends on other compounds’ presence.
On the other hand, soft water is rich in sodium, which allows the acidity to shine, but it doesn’t mean that it’s always better. Water with high calcium and magnesium levels will extract more flavors and acids.
So what to do? If your coffee is sour, dull, and lifeless, but you know it isn’t due to the coffee or your brewing, try changing the water. Use a filter or bottled water to see how the coffee tastes change.
The technique of combination of water and coffee is what makes the taste. Mixing coffee and water leads to the extraction, meaning the slow diffusion of coffee flavor and aroma compounds from coffee beans to water. The way you extract your coffee will influence the sweetness, balance, and bitterness of the coffee. Over-extracted coffee will be more bitter than under-extracted one. You have to strike the right balance depending on your personal preference. You just have to try different techniques and make mistakes to find out what you genuinely like.
Grind Size and Extraction
If you want to achieve a sparkling acidity, you may want to use a coarser grind. Because of its smaller surface area, the extraction is much slower, but it can result in sourness when taken too far. Summing up, if you want more acidity, you have to grind coarser, and if you like sweeter coffees, use fine grinds.
The extraction rate can also be impacted by the temperature of the water you use. The hotter the water, the faster the compounds will extract. However, some of them won’t do it at certain temperatures, and that’s why cold brew has a different taste. Moreover, remember that temperature interacts with grinding size, brewing time, etc.
Lowering the Acidity
Those who deal with the more constant acid reflux version often have trouble pinpointing the reason for the discomfort. If you drink coffee, therein may lie the root cause of your acid reflux. Even occasional heartburn can stem from a cup unless the coffee in the cup reduces acid coffee. So what is the best way to do it?
Cold brewing effectively neutralizes the acids in coffee, as it uses cold water instead of hot to extract the flavor from beans. As a result, it contains 70% fewer acids than regular, hot brewed coffee. The only downside is that you have to prepare it in advance, as it has to sit in the water for at least 12 hours (although it is best to leave it for 24). As you can see, it is not suitable for people in a hurry.
It may seem weird to use eggshells when making coffee, but this method actually works. They are very alkaline, which works to neutralize any acid you may want, and they can also reduce bitterness. The only thing you need to do is to take one or two eggs, rinse them in the water and break them. Use the egg inside to make breakfast or leave it for later in the fridge, and break the shells in your hands. Then, place the crushed eggs into your coffeemaker and brew as usual.
You should add salt to the grounds or the finished brewed cup, as it can add smoothness and reduce bitterness. It can also work wonders if you want to neutralize the acid in coffee to decrease an acid reflux flareup’s chances. Just add one small pinch into your cup.
The Bottom Line
Coffee is an integral part of many people’s lives. It can be a means for additional energy, a hobby, or even a job. The coffee pH point lies in-between. Although it’s not quite acidic, it is also not entirely neutral.
Coffee lovers are all around us, and like all people, there are various problems involved. Certain health conditions can affect our lives and prevent us from doing what we love. Fortunately, there are some solutions for most of them. These several methods of reducing the acidity of coffee can prove very helpful, and they can allow you to enjoy your morning cup of coffee without pain and discomfort.