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Why Does Coffee Smell Like Cat Pee?

As an avid coffee lover, you have probably tasted coffee that smells like ammonia, skunk, or poop. Worse still, you might have come across a cup of coffee that smells like cat pee. Such smells can put you off. But why does coffee smell like cat pee? Keep reading to find out.

coffee smell cat pee

What Should Coffee Smell Like?

Before we discuss why coffee may have such a strange smell like cat pee, it will help to know the basics of coffee smell. Essentially, the natural aroma of coffee is mainly a result of the acids in coffee beans. Coffee beans have different acids depending on the variety and how it was grown and processed.

Primary coffee acids in coffee include acetic (vinegar smell), citric (citrus scent), and mild (green apple scent). The proteins and fat in coffee beans also contribute to their smell. The scent of coffee is made up of about 50 compounds. These compounds vary in concentrations and ratios. Thus, different coffee blends may have different fragrances.

Before roasting, coffee beans have approximately 200 aroma compounds. These compounds increase to at least 800 odor compounds upon roasting. It is these aroma compounds that smell different like rancid, burnt, fruity, or cat pee.


Why Would Coffee Smell Like Cat Pee?

If you notice your coffee smelling like cat pee, it might be a result of certain things such as:


1. Improper coffee roasting

It is typically rare to find popular coffee beans on the market smelling like cat pee. However, this issue often happens when roasting coffee beans at home. The roasting process of coffee beans requires following strict standards. You must get the temperature and timing right. As such, the roasting tools, environment, and conditions should allow for the best roasting outcome, or else you will waste your coffee beans.


2. Brewing with stale coffee beans

The quality of the coffee beans you use to brew coffee largely determines the final taste of your drink. During roasting, coffee beans produce various gases including carbon dioxide (C02). The beans continue releasing CO2 after roasting. The more CO2 they lose, the blander they taste. Thus, you should preserve coffee beans properly for the best taste. If you store them for too long, they will brew coffee that smells like cat pee.

Research shows that coffee beans lose 10 percent of their flavor every 24 hours when exposed to room-temperature air. The loss is due to the release of CO2. Although a 10 percent loss may sound small, it is a significant loss for serious coffee lovers.

Preferably, avoid stocking up coffee beans. We recommend you buy a supply you can consume within 1 to 2 weeks. A 1-week supply will give you optimal freshness. Ensure to check the roasting date on the packaging instead of the expiration date. Do not use the beans for at least 4 days after roasting to allow them to degas for a more flavorful taste.


3. Failure to brew at the right temperature

The recommended temperature for brewing coffee is 96 degrees Celsius. Research shows that optimal extraction occurs at this temperature. If you exceed the temperature, the excessive heat will decompose the aroma of coffee beans. On the other hand, if the water is not hot enough, the brew will taste half-baked.


4. Brewing with dirty equipment and impure water

The kind of water you use to brew coffee also determines its final taste and aroma. Probably, impurities have found their way into your tap water. The impurities may cause unwanted reactions that can make your coffee smell like cat pee.

Also, brewing with a coffee pot that is not thoroughly clean can introduce foreign tastes and smells to your coffee. Also, impurities in cups, spoons and other utensils you use when making coffee can affect its smell and taste. Always wash your utensils and washable coffee maker components thoroughly after brewing coffee.


Can You Fix Coffee That Smells Like Cat Pee?

So why does coffee smell like cat pee? By now, you have answers to this question. Unfortunately, it is impossible to reverse this problem once it occurs. If the beans have overstayed, throw them away and get a fresh supply. If you must roast coffee beans at home, get the roasting process right. Also, brew coffee at the right temperature using clean equipment and pure water. That way, your coffee will not have any strange smells.