Why Does Instant Coffee Go Black?

Table of Contents

There are many different chemical reactions that take place in coffee to get it the right color and taste. The type of chemical reaction that takes place determines what will happen next with the mixture. Black coffee is the result of some of these reactions.

The chemical make-up of coffee determines when it can turn black. This also applies to instant coffee. Certain compounds in the coffee mixed in with a different additive, such as sugar or creamer, will affect the chemical make-up of the coffee and cause a chemical reaction.

When instant coffee starts to turn black, that means there is a chemical reaction taking place within the components of the substance. This chemical reaction will be discussed as well as a few other reasons why your instant coffee might turn black.

The Maillard Reaction

The Maillard Reaction is a chemical reaction that takes place between amino acids and reducing sugars that give browned food a distinctive taste. This reaction happens in roasting marshmallows, bread, cookies, etc. This reaction only happens when the reducing sugars and amino acids are impacted by heat. For when the reducing sugars and amino acids interact they create a compound called glycosylamine (source).

A chemical reaction is required for different outcomes of certain types of variables. A chemical reaction is a process of one or more substances, (the reactants), being converted to one or more substances, (the product).

The reaction starts to occur in between the temperatures of 140 – 165 degrees Celsius (284 – 329 degrees Fahrenheit). This reaction takes place in coffee when the coffee beans are roasted. The roasting of the coffee beans brings out the different types of flavors and colors that people love to drink daily. In order to get the type of coffee you desire, whether instant or not, the beans have to go through this roasting process.


Acrylamide is a chemical that can form in certain foods during the heating process. For example, when coffee beans are roasted, acrylamide forms. This chemical can be potentially harmful to the human body if too much is consumed. This has to be regulated because this chemical reaction can hurt the body in different ways. Some symptoms are muscle weakness and nerve damage. Acrylamide is found not just in foods, but in household items, personal care items, and smoke (source).

Moisture in Coffee

Instant coffee is a hygroscopic type of substance. Hygroscopic is the phenomenon of a substance that absorbs and retains moisture from the atmosphere or surrounding environment. Water vapor from the atmosphere will be absorbed into the pores and external surface, to form a condensed layer. A hygroscopic material will either absorb or release moisture until it has reached its equilibrium (source).

There are many variables that could cause your instant coffee to be super black and solid. For example, it can happen if the container was not sealed properly in the production line or if you live in a humid climate. As you can see, there are many different causes that can take place to create this reaction to take place with this product.

In a situation where your instant coffee has absorbed all of the moisture, it can make it extremely difficult for people to enjoy the coffee. At this point, the coffee starts to become distasteful and more difficult to drink. Most people discard it because of this, and for good reason.

One important reason to keep in mind is food safety. With the humidity and moisture in the can and coffee, there is a chance of growing bacteria and fungus.

Chemical Make-up

A chemical make-up or chemical composition refers to the arrangement, type, and ratio of atoms in molecules in a chemical substance. Chemical compositions have the ability to change when things are added to a chemical substance or there is a chemical reaction inside the chemical. So in terms of coffee, heating it or adding other things to it may cause a difference in the color or taste of the drink.

Each chemical composition has different chemical constituents. A constituent is something that is necessary to make something else whole. That applies to any ingredient in a chemical that has a particular mixture. The main constituents of coffee are known as caffeine, tannin, carbohydrates, protein, and fixed oils. Other known chemical ingredients are Thiamin, Xanthine, Speridime, Guaiacol, Citric acid, Chlorogenic acid, Acetaldehyde, Spermine, Putrescine, and Scopoletin.

Chemical Formula

With every chemical composition, there is always a chemical formula. A formula may not seem important to those on the outside looking in, but it can prove useful. The molecular formula is C25H28N6O7. While the chemical formula for caffeine is C8H10N4O2. Meaning that coffee is made up of carbon, hydrogen, nitrogen, and oxygen. These formulas appear as a crystalized shape when examined to hold the components (source).

Chemical Acids

There are many different acids in coffee. One of the many types of acids that are out there, and within coffee, is a nonvolatile acid. A nonvolatile acid is a metabolic acid that is produced from an incomplete metabolism of carbohydrates and protein. This is important because citric acid and chlorogenic acid fall under this category. These acids can give taste to the substance of the product. For example, chlorogenic acids are one of the richest acids in coffee.


Coffee contains about 2-3% of caffeine, but when it is in the seeds it is presented as a salt of chlorogenic acids. A coffee drink has about 10% of caffeine and 6% of chlorogenic acids in it. Roasting the coffee beans decreases the natural amount of caffeine in coffee and comes out to a total of 2-3%. So companies put synthetic caffeine in the drinks to give the drinks more of a bitter taste than they should have.

In using synthetic caffeine they have to obtain it from uric acids and formamide. Synthetic caffeine is produced with a higher concentration than natural and is absorbed faster in the body. With synthetic caffeine, you are given a faster boost and have quicker energy at the moment but have a quicker crash afterward. This can cause instability in the body and can create other health problems if not regulated.

Shmulik Dorinbaum

Shmulik Dorinbaum

40 years old, from the age of 20 when I left the army until today, I drink more than 4 cups of coffee, only instant coffee, so I decided to write about my great passion that occupies me most of the day

About Me

40 years old, from the age of 20 when I left the army until today, I drink more than 4 cups of coffee, only instant coffee, so I decided to write about my great passion that occupies me most of the day

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