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Coffee Tips

Why Does Coffee Smell Like Poop?

Coffee is among the most popular beverages in the world. It has different tastes and aromas, most of them appealing. But, have you ever bought coffee expecting the usual pleasant aroma, only to smell poop? If you’ve been through this, you’re not alone. Many coffee lovers have been through this situation at least once in their lifetime.

The paramount reason as to why your coffee smells like poop is a result of over-roasted coffee beans. Excessively roasted coffee beans create a smell that is strong and unpleasant. This is because the oils in the coffee beans have been exposed to too much heat.

Over-roasted coffee beans sometimes smell like cat litter or tuna. This article will discuss why your coffee smells like poop and how to resolve the problem. Keep reading.

bad coffee smelling like poop

Reasons Why Your Coffee Smells Like Poop

  1. Over-Roasted Coffee Beans

As mentioned earlier, the key reason behind the poop smell in your coffee is over-roasting coffee beans. Once coffee beans are over-roasted they release oils and strong smells that may resemble poop or cat’s pee. Additionally, your coffee tastes sour and unpleasant. The poop smell in coffee isn’t good for anyone drinking the coffee since they’ll end up smelling like poop.

The logic behind the poop smell in coffee is that coffee beans contain oils and minerals such as potassium and magnesium. So, once the beans are roasted under high temperatures, the contents in them are activated, thus releasing strong and rich aromas that are the characteristics of the different types of roasts.

You’ll find that darker roasts have a more pungent smell and unpleasant flavor. This is because the coffee beans have been roasted longer, thus the more the activation of the oils and minerals. If you want to avoid the poop or cat pee smell in your coffee, consider buying lightly roasted coffee beans.


  1. Degassing

Another reason why your coffee smells like poop is a result of Oxidation. Oxidation refers to the contact of roasted coffee beans with oxygen gas. Oxidation may occur while the coffee beans are degassing, which is the process of releasing gasses from roasted coffee beans. So the poop smell may result from the reactions that occur as a result of contact between coffee beans and oxygen.

Oxidation in coffee beans results in vinegary-smelling and rancid-tasting coffee beans. Additionally, coffee beans’ exposure to light, higher temperatures, and air will result in a burnt or plastic taste in your coffee. This is because coffee beans become rancid when exposed to light, heat, and air.

If you experience rancid coffee beans, consider throwing them away since it means that they’re stale. Additionally, store your coffee beans in an airtight container, away from light and heat or sunlight to avoid chances of oxidation.


How Should Your Coffee Smell?

As mentioned earlier, different coffee beans will produce different smells. Additionally, the roasting of the coffee beans will also affect the aroma as well as the flavor. More often your coffee should have a pleasant aroma – the aroma should be strong but in a way, it’s not overwhelming. The taste should also be pleasant to your mouth.

Usually, coffee beans are roasted at high temperatures to create aromatic oils that are sometimes pleasant to smell and other times unpleasant. You’ll find that dark roasted coffee beans are more prone to poop or cat’s pee smell. This is a result of over-roasting. Generally, a perfect cup of coffee should have a pleasant smell – lightly caramelized and almost nutty, while stale coffee smells musty and cardboard-like.


Can Your Breath Smell Like Poop as a Result of Coffee?

Caffeine in coffee can make your breath smell like poop. This is because caffeine lowers the saliva production in your mouth, leading to bad breath. Usually, saliva in your mouth is responsible for killing the bacteria present and causing some initial digestion. So, once the saliva lessens, the bacteria responsible for bad breath are not killed so they multiply in number.

Foods in your mouth are also not digested properly and completely, so the bacteria break down the food themselves, contributing to the bad smell. Additionally, coffee contains a high sulfur concentration that’s broken down by the bacteria, leading to a bad smell. Equally important, over-roasted coffee has a strong unpleasant smell that makes your breath smell like poop.


How to Avoid the Poop Smell in Your Coffee and Breath?

Apart from over-roasted coffee beans, there are other reasons why your coffee smells like poop. They include additives such as sugars and creams. Usually, bacteria live on sugar and are a result of the bad smell of your coffee.

The first thing you need to do to avoid the poop smell in your coffee is to use lightly roasted coffee beans. After doing that, you can use sugar alternatives in your coffee such as vanilla beans, and cinnamon sticks.

Adding milk also helps in reducing sugars and bacteria since milk contains natural sugars. Some other remedies you can try to avoid the poop smell include:

  • Storing your coffee beans properly in airtight containers and far from sunlight, heat, and air to avoid oxidation. Additionally, ensure the coffee beans are fully dry before storing them.
  • Brush your teeth after drinking coffee
  • Drink plenty of water to prevent bad breath



Coffee is a widely consumed beverage. However, if your coffee smells like poop, try some lightly roasted coffee beans. Additionally, avoid too much consumption of coffee to avoid the poop smell since caffeine in coffee lowers your amount of saliva. This causes more bacteria in your mouth, which contribute to the bad smell. Also, store your coffee beans properly to avoid oxidation which may lead to rancid coffee beans.


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