When it comes to coffee, most people are interested in the caffeine content. However, coffee is composed of mostly water. In fact, coffee is around 98% water. The other 2% is made up of caffeine, oils, acids, and other plant matter. This means that for every 100 grams of coffee, only 2 grams are other compounds.
I know that when I grab a cup of coffee in the morning, I’m mostly getting water. But it’s the other 2% that makes coffee so unique.
It’s important to know the other compounds in my coffee. After all, caffeine is what gives me the energy I need to get through the day, but the rest gives us the fantastic flavor we all love.
Knowing what percentage of coffee is water is only the beginning. If you want to learn more about the other compounds in your coffee, keep reading!

Coffee composition
Coffee is more than just a morning pick-me-up. It’s a complex beverage made up of over 1,000 different compounds. And while most of these compounds are present in tiny amounts, they play a significant role in determining the flavor, aroma, and body of the final cup.
Of all the coffee compounds, caffeine is by far the most well-known. But despite its widespread popularity, caffeine is actually only present in coffee at levels of 2-3%. So while it may be the compound that gives coffee its signature kick, it’s certainly not the only player in the game.
Tannins are another vital component of coffee. These bitter-tasting compounds are responsible for giving coffee its astringent quality. Tannins are also believed to help balance out the sweetness of coffee, and they play a role in determining body and mouthfeel. Fixed oils are another key component of coffee. These oils give coffee its rich flavor and smooth texture. And finally, carbohydrates and proteins round out the list of significant coffee compounds. Carbohydrates contribute to sweetness, while proteins add complexity and depth of flavor.
So next time you take a sip of your favorite brew, remember that there’s a lot more going on beneath the surface. Each compound plays an important role in giving coffee its unique flavor and character, from caffeine to tannins.

Breakdown of coffee components

Now that we’ve covered the basics let’s dive a little deeper into the world of coffee composition.
Coffee is comprised of four main groups of compounds: alkaloids, oils, carbohydrates, and proteins.
Alkaloids are a group of compounds that includes caffeine. These bitter-tasting compounds are soluble in hot water, which is why they’re easily extracted from coffee beans during the brewing process.
Oils are another key component of coffee. These flavorful compounds are responsible for giving coffee its characteristic aroma and taste. Coffee oils are also responsible for the body and mouthfeel of coffee.
Acids are another important group of compounds found in coffee. These sour-tasting compounds contribute to the overall taste and aroma of coffee.
The plant matter is the final group of compounds found in coffee. This category includes tannins, which contribute to the astringent quality of coffee, as well as other minerals and vitamins that are present in small amounts.
These are the four main groups of compounds that make up your cup of joe.
But what about caffeine in coffee?
Let’s take a closer look at the most beloved compound in coffee: caffeine.
Caffeine is a bitter-tasting alkaloid that’s found in coffee beans. This compound is soluble in boiling water, allowing it to be readily extracted during the brewing process. Caffeine is also responsible for coffee’s stimulating effect on the human body.
Caffeine belongs to a class of compounds known as methylxanthines. These molecules are also found in chocolate and tea. Methylxanthines are believed to work by inhibiting the action of a neurotransmitter called adenosine. Adenosine is responsible for inducing feelings of fatigue, so by inhibiting its activity, caffeine helps to keep us awake and alert.
Caffeine has a variety of effects on the human body, including increased alertness, improved mood, and enhanced physical performance. Caffeine is also known to increase heart rate and blood pressure.
While caffeine is generally considered safe, it can be harmful in large amounts. Caffeine overdose can lead to symptoms like anxiety, restlessness, and irritability. In extreme cases, caffeine overdose can even lead to death.

How important is water in making coffee?
Having delicious, fresh filtered water is the key to brewing great-tasting coffee.
Water is responsible for extracting the flavor from coffee beans. This is why it’s essential to use fresh, filtered water when making coffee.
While the exact ratio of water needed for brewing coffee varies depending on the type of bean and grind, a general rule of thumb is to use about two tablespoons of coffee to eight ounces of water.
Keep in mind that the quality of the water you use will directly impact the flavor of your coffee. This is why it’s important to use fresh, filtered water when brewing coffee.
Why is filtered water better for making coffee?
Do you know what’s in your drinking water? Chances are, you don’t.
While most tap water is safe to drink, it can contain impurities that can impact the flavor of your coffee. This is why filtered water is always the best choice for making coffee.
Filtered water has been treated to remove impurities like microscopic particles, chlorine, radium, lead, and arsenic. This results in water that’s free of contaminants and has a neutral pH.
There are also special coffee water additives that you can use to further improve the flavor of your coffee.
When it comes to making great-tasting coffee, water is key. Because coffee is basically water, be sure to use fresh, filtered water for the best results.

What other factors affect the taste of coffee?
In addition to the type of bean and grind, there are a few other factors that can impact the flavor of your coffee.
The first is the brewing method. Different brewing methods extract different flavors from coffee beans. For example, French press coffee is known for its rich, full-bodied flavor, while drip coffee is known for its more mellow taste.
The second factor is the roast level. Coffee beans can be roasted to different levels, from light to dark. The roast level affects the flavor of coffee, with darker roasts typically being more bold and full-bodied.
The third factor is the water temperature. When brewing coffee, it’s important to use water that’s just below boiling. If the water is too hot, it can extract bitter flavors from the beans. If the water is too cold, it can make coffee taste weak and watered down.
The fourth factor is the grind size. The grind size affects the surface area of the coffee bean that’s exposed to water. A finer grind will result in more flavor being extracted from the beans, while a coarser grind will result in less flavor being extracted.
The fifth and final factor is the brew time. The longer your coffee is brewed, the more flavor will be extracted from the beans. This is why it’s crucial to not over brew coffee, as doing so can result in a bitter taste.
What are the best coffee beans for brewing coffee?
When drinking coffee, it’s important to choose beans that are fresh and of high quality. This is why most coffee aficionados recommend buying whole beans and grinding them at home just before brewing.
There are a few different factors to consider when choosing coffee beans, including the type of bean, the roast level, and the grind size.
The type of bean is the most essential factor to consider. Arabica beans are the most popular type of coffee bean and are known for their balance of sweetness and acidity. Robusta beans are popular in places like Vietnam, where they’re used to make strong, bold coffee.
There are many different types of coffee beans, each with its own unique flavor. The best coffee beans for brewing coffee depend on your personal taste preferences.
Some of the most popular types of coffee beans include:
- Columbian beans
- Brazilian beans
- Costa Rican beans
- Sumatran beans
- Ethiopian beans
- Kenyan beans
- Guatemalan beans
- Mexican beans
No matter what type of coffee bean you choose, be sure to buy them from a reputable source. Freshness is key when it comes to brewing great-tasting coffee.
Does coffee count towards your daily water intake?
The water content in a good cup of coffee does count towards your fluid intake. Hydration is important for your overall health, so it’s good to know that coffee can help you stay hydrated.
That being said, it’s important to remember that coffee has a slight diuretic effect, which means it can cause you to urinate more frequently. This can lead to dehydration if you’re not careful.
To avoid dehydration, be sure to consume other fluids to increase your hydration levels. Sports drinks are better than black coffee when it comes to hydration, but water is always the best option.
Final Thoughts
While caffeine is the most well-known compound in coffee, coffee lovers know water is actually the key to brewing great-tasting coffee. In order to extract the most flavor from coffee beans, it’s important to use fresh, filtered water. There are a variety of factors that can affect the taste of coffee, including the type of bean and grind, as well as the brewing method, water temperature, and grind size. By taking all of these factors into account, you can brew delicious coffee that’s tailored to your specific taste preferences.
As always, experiment with different beans, grinds, and brewing methods to find what you like best. There’s no wrong way to make coffee, so have fun and enjoy the journey. Happy caffeinating!