Coffee Tastes Burnt? Causes and Solutions

Burnt coffee can also be described as smoky or ashy, but more importantly, it can be virtually undrinkable. There are several possible causes. The causes can be the coffee beans or the coffee machine.

Sometimes coffee tastes burnt due to the roasting. Then we can just substitute the beans. However, more often than not, the burnt taste is due to an error during the brewing process.

It is also important to note that there are differences between burnt coffee and bitter coffee.

Difference between burnt and bitter coffee

Coffee can be bitter, but bitterness doesn’t necessarily mean an unpleasant taste, even though it’s one of the hallmarks of burnt coffee.

A really unpleasant bitter taste with no other flavors is an over-boiled coffee. This tastes like charcoal, but not in a pleasant, smoky way.

The taste of burnt coffee is an unpleasant mix of ash, bitterness, and burnt roast aromas. These properties result from the complicated chemical reactions that take place when the coffee beans are roasted.

In general, there is a strong resemblance between burnt coffee and bitter coffee. In fact, in most cases, the reasons for bitter and burnt coffee are similar, e.g. B. brewing with water that is too hot or using old beans.

How do you recognize burnt coffee?

You can easily tell if a coffee is burnt by its strong taste. It’s a flavor that conveys the sensations of a campfire, which can also be accompanied by an obvious overcooking if left on the heat for too long.

Maybe you can smell it before you even taste it. Guessing the taste of coffee based on the aroma is an exercise that gets refined with each exercise. If you already suspect a coffee might be faulty based on the smell, you might not need to try it at all.

Specialty Coffee Association of America Flavor Wheel

The Specialty Coffee Association of America (SCAA) offers a handy aroma wheel . First printed in 1995, this wheel catalogs the different tastes, nuances, aromas and notes found in a cup of coffee.

Within the Roasting category there is a sub-category called “burnt”. Various notes are found in this section, including “brown roast”, “smoky” and “ash”. Some of these flavors are intentionally added to the coffee, others are the result of errors in the brewing process.

Smoky and ashy flavors are more common in dark roasts. In this case, the method of darkening the beans with heat is said to produce smoky and ashy flavors to be enjoyed.

Reasons why coffee tastes burnt

A single mistake is enough to turn the taste into burnt. Below we address the most common mistakes that can lead to a burnt cup of coffee.

Too hot water

A water temperature that is too high can affect the quality of the coffee, as it can lead to a so-called over-extraction of the coffee, which can result in a burnt taste.

To avoid this problem, you should make sure that the water is at the ideal temperature. According to the National Coffee Association of the United States, the water should be used at a temperature between 90°C and 96°C (194° – 205° Fahrenheit).

A flavor produced with very hot water is slightly different from a burnt flavor obtained from darker roast beans. However, they are so similar that it is difficult to tell them apart.

Higher temperature water extracts more flavor, but also more aromas. At temperatures above 96°C (205°F), most of the extra flavors extracted are very strong flavors that many people dislike.

Incorrect ratio of water to coffee

Sometimes there may be too much coffee in the water. This changes the composition of the coffee and gives it a more burnt and sometimes bitter taste.

In general, the ratio varies between 10:1 and 18:1 and depends on the extraction method to be used.

Burnt or stale coffee beans

In most cases, it is the coffee beans that are responsible for the burnt taste of the coffee. This is when the beans have not been roasted properly and may have any of the following characteristics:

  • Coffee beans are partially green.
  • Coffee beans appear too dark and greasy.
  • The mixture consists of burned and normal looking beans.

Any roasting error affects the taste of the coffee. More aromatic flavors may be lost, or burnt and bitter flavors may be enhanced.

Well, there is nothing wrong with dark roasted coffee beans. Some people even prefer this strong taste. It just comes down to buying quality coffee from a reputable retailer or with a reputable guarantee.

On the other hand, it can be useful to store the ground coffee in an airtight container after opening the package so that it does not go rancid too quickly. Oxygen is the enemy of every coffee.

Dirty or non-functioning brewing equipment

Impurities in the coffee maker can affect fresh coffee beans. This can cause them to have a burnt taste. Proper cleaning of the coffee maker, reusable filters, milk frother, and every other utensil you use to brew a cup will greatly improve the taste.

With regular use, deposits can form inside the coffee machine, affecting the quality of the coffee.

Brewing process

The brewing method used can be responsible for why the coffee can taste burnt. For example, drip machines tend to make the coffee burnt and bitter because they use boiling water. Automatic coffee makers often use built-in water heaters that are programmed to boil the water before pouring it through the coffee.

In addition, the drip machines often do not succeed in distributing the water evenly over the coffee. As a result, part of the coffee becomes oversaturated while another part remains dry. Oversaturated coffee beans will cause over-extraction, as will boiling water.

How to prevent burnt coffee taste?

To avoid the unpleasant burnt taste, there are a number of preventive measures:

  • If possible, you should regulate the water temperature of the coffee maker. Make sure the water isn’t too hot or too cold as this will change the taste of your coffee.
  • Pay attention to high-quality coffee. Using low-quality coffee can result in burnt-tasting coffee.
  • Choose the right degree of grind for your coffee. There are differences depending on the type of coffee and the extraction method.
  • Always make sure to clean all utensils regularly. You should also descale your coffee machine once a month.

Can burnt coffee affect your health?

Some scientific studies have found that roasted beans contain small acrylamide compounds. A substance that can be carcinogenic, especially when consumed regularly, such as coffee every day.

What is acrylamide?

Acrylamide is a chemical found in burnt coffee. Just like in all types of coffee that are roasted. It is a chemical that can cause serious problems in the body.

Acrylamide can cause cancer if people regularly drink burnt coffee for several years or decades. This chemical has been shown to be present in high levels in roasted coffee due to the processing method.

In addition, the acrylamide content in coffee varies greatly. A 2013 study found that instant coffee contains 100% more acrylamide than freshly roasted coffee. In addition, the acrylamide content peaks at the beginning of the heating process and then decreases. Therefore, lighter coffee beans contain more acrylamide than darker beans that are roasted longer.

However, levels of this substance in coffee are low, and no studies have been found to indicate a high risk of cancer compared to the benefits of coffee consumption. There are even several studies claiming that coffee can prevent various types of cancer. However, the general recommendation is always “the amount makes the poison”.


Burnt coffee is usually a problem that can be solved with a few simple changes to the brewing process. In addition, you should also check other points such as the roasting or the coffee brewing equipment.