The science of how water interacts with coffee is a complex and fascinating process. When you add water to coffee grounds, the water begins to extract the soluble compounds and oils from the coffee, resulting in a flavorful and aromatic brew.

Multiple Factors

The first step in this process is wetting the coffee grounds, which causes them to expand and release carbon dioxide. This step is known as blooming, as it describes the literal expansion the grounds undergo when water is added, and it is an essential part of the brewing process. Blooming allows the carbon dioxide to escape, which prevents over-extraction and helps to ensure an even extraction of the coffee.

Next, the water begins to dissolve the soluble compounds in the coffee, such as caffeine, acids, and sugars. These compounds give the coffee its flavor, aroma, and body, along with that much needed caffeinated kick to your day. The degree to which these compounds are extracted depends on several factors, including the coffee-to-water ratio, the grind size, and the water temperature.

The water also interacts with the oils in the coffee, which contribute to the overall mouthfeel and texture of the coffee. These oils are released during the brewing process, and they are responsible for the crema on top of an espresso shot and the richness of a French press brew.

Finally, the water carries these extracted compounds and oils through the filter and into your cup. The balance of these compounds and oils is what determines the flavor, aroma, and body of your coffee.

But what does it mean when your cup of coffee tastes watery? And what can you do in order to prevent and improve your coffee in future brews?

Reasons Why is My Coffee Watery

If you’ve ever taken a sip of your coffee and found it to be weak and watery, you’re not alone. There are a few reasons why your coffee might taste this way, and understanding these reasons can help you make adjustments to your brewing process to achieve a stronger, more flavorful cup. Here are a few reasons:

1. Improper Coffee to Water Ratio: One of the most common reasons why coffee turns out watery is because of an improper coffee to water ratio. If you’re using too much water and not enough coffee, your coffee will be weaker and more watery in taste. As a general rule of thumb, aim for a ratio of 1-2 tablespoons of coffee per 6 ounces of water. Adjust the ratio according to your personal preferences, but try not to stray too far from this guideline.
2. Poor Quality Coffee Beans: Another reason why your coffee might be watery is because of the poor quality and roast of the coffee beans. If your beans are stale or of low quality, they won’t release as much flavor and aroma during the brewing process, resulting in a weak and watery cup of coffee. To avoid this issue, make sure to use freshly roasted beans and purchase from a reputable coffee supplier, like Volcanica.
3. Incorrect Grind Size: The size of the coffee grounds can also affect the strength and flavor of your coffee. If your coffee is too watery, it may be because the grind size is too coarse. This can cause the water to pass through the grounds too quickly, resulting in a weak and under-extracted brew. Try adjusting the grind size and experiment with different settings to find the perfect balance. You will notice that the coffee being too coarse not only from sight of how large the grind it but also the brew time of your coffee will be too quick, and thus not extracting enough of the solubles from the coffee.
4. Water Temperature: Finally, the temperature of the water can also affect the strength and flavor of your coffee. If the water is too cool, it won’t extract enough flavor from the coffee grounds, resulting in a weak and watery brew. On the other hand, if the water is too hot, it can over-extract the coffee, resulting in a bitter and unpleasant taste. The ideal water temperature for brewing coffee is between 195°F and 205°F.
5. Another common reason is that the coffee is under-extracted: This means that not enough of the soluble compounds and oils have been extracted from the coffee grounds, resulting in a weak and watery brew. Under-extraction can be caused by a variety of factors, including using too little coffee, using a grind that is too coarse, or brewing for too short of a time.
6. Over-dilution: This can happen when you add too much water to your coffee, either by using too much water in your brewing process or by adding too much hot water to your cup. Over-dilution can also occur when you use a brewing method that doesn't allow for a full extraction of the coffee, such as a drip coffee maker that doesn't brew for long enough.
7. Water quality can also affect the taste: If the water you're using to brew your coffee is too soft or too hard, it can result in a weak and watery brew. Hard water, which contains high levels of minerals like calcium and magnesium, can also affect the extraction process and result in a less flavorful cup of coffee.

All of these variables can be modified and played around with in order to dial in to your ideal cup of coffee. You can change the grind, the water temperature, and the way in which you brew your coffee to easily lead to your ideal cup of coffee that doesn’t taste watered down. By understanding these factors and making adjustments to your brewing process, you can enjoy a stronger and more flavorful cup of coffee.

There are a lot of different variables that can affect the flavor and dilution of coffee, and at times it can seem overwhelming. But there are very simple and effective changes that you have in your arsenal as a home barista that can help mitigate any water-related issues that may crop up in your home brewing efforts. 

Trial and Error 

In conclusion, watery coffee is a common problem that can be caused by a variety of factors, including under-extraction, over-dilution, and poor water quality. To avoid watery coffee, it's important to pay attention to the brewing process and make sure that you're using the right amount of coffee, grinding the beans to the correct size, and brewing for the appropriate amount of time.

Another key factor to consider is the quality of the water you're using. Using high-quality water that is free from impurities and at the appropriate level of hardness can help to ensure that you get the best possible flavor from your coffee.

If you're still experiencing issues with watery coffee, it may be worth experimenting with different brewing methods or adjusting your brewing process to see if you can improve the taste. Don't be afraid to try new things and make adjustments to find the perfect balance for your taste preferences.

Ultimately, with a little bit of experimentation and attention to detail, you can avoid the frustration of watery coffee and enjoy a delicious and satisfying cup every time.