MHW-3BOMBER - Dec 18 2024
Why Does Coffee Taste Sweet? Where Does the Sweetness Come From?
When you visit a coffee shop, you often hear baristas mention flavors like cane sugar or caramel sweetness. However, when you take a sip, you might not taste any of that sweetness. So, the question arises: Where does the sweetness in coffee actually come from? Why can some people taste it, but others can’t?
What is the Sweetness in Coffee?
In reality, coffee is not inherently bitter. It's important to know that coffee beans contain about 50% carbohydrates, which include sucrose, pectin sugar, mannitol, glucose, galactose, and other types of sugars. Of course, not all of these sugars dissolve in water. Only a small portion of them can “enter” the coffee and be perceived by us as sweetness.
What Factors Affect the Sweetness of Coffee?
1. Variety and Origin
The variety of coffee beans and the region in which they are grown have a significant impact on sweetness. Some coffee bean varieties naturally contain more sugar. For example, Arabica beans typically have more natural sugars than Robusta beans, giving Arabica coffee a sweeter taste.
2. Altitude
Coffee grown at higher altitudes tends to have a more complex sweetness. At higher altitudes, the air pressure is lower, and there’s less oxygen, which affects the growth of coffee trees. To adapt, the trees grow slower, giving them more time to accumulate and store sugars. The slower growth process results in richer sugar content compared to coffee grown at lower altitudes.
Additionally, high-altitude regions typically receive stronger sunlight, even though the daylight hours are shorter. The thin air allows for more intense ultraviolet rays, causing plants to enhance their photosynthesis and convert more solar energy into sugars and nutrients. Therefore, coffee trees grown at higher altitudes usually accumulate more sugar.
By contrast, why do beans from low altitudes tend to taste more bitter and astringent?
This is due to the chlorogenic acid found in coffee beans! Low-altitude regions often have more pests, and the higher temperatures and dryness lead to increased chlorogenic acid production in the beans. In high-altitude areas, where pests are less of an issue and the temperature and humidity are more suitable, the level of chlorogenic acid is naturally lower.
3. Processing Method
The method used to process coffee beans also influences their sweetness. For instance, natural drying (or sun-drying) typically preserves more sugars and flavors in the beans, resulting in a sweeter taste. On the other hand, beans processed through the washed method tend to have more acidic flavors, as this method removes some of the sugars and compounds that contribute to sweetness.
4. Roasting
The degree of roasting affects the sweetness of coffee. After the first crack (the point when the beans begin to pop during roasting), sugars in the beans are transformed into caramel, especially sucrose. It’s important to remember that coffee is, after all, a fruit. Lightly roasted coffee beans usually retain more of their natural sugars and complex fruit acids, which emphasize the sweet and acidic notes.
Interestingly, the longer the roasting time, the more complex the sugars become. The Maillard reaction and caramelization during roasting create new flavor compounds, some of which enhance the sweetness of the coffee. Yes, the sweetness can be so intense that it even masks some of the bitterness — it’s not just a figure of speech!
5. Brewing Method
After roasting the sweet beans, the final step is extraction! How do we bring out the sweetness in coffee? This is a challenge faced by many baristas and coffee enthusiasts. The goal is to find the right balance — extracting enough sweetness while also controlling the brewing process. If the extraction time is too long (over-extraction), the coffee may become overly bitter, which can mask the sweetness. Conversely, if the extraction is too shallow, the sweetness might not be fully extracted.
The Expression of "Sweetness" in Coffee
1. Natural Sweetness
Good coffee often exhibits a natural sweetness that balances with other flavor elements such as acidity and bitterness, creating a complex and rich taste profile. For instance, some coffees may present sweetness reminiscent of fructose, honey, syrup, or even candy. This type of sweetness comes from the sugars naturally present in the beans and is enhanced by factors like the coffee's variety, growing conditions, and processing methods.
2. Caramel Sweetness
Dark-roasted coffee often carries a caramelized sweetness. This flavor comes from the breakdown of sugars during the roasting process, where sugars are converted into caramel and other sweet compounds. Typically, this type of sweetness is milder and smoother, giving the coffee a rich, warm feeling, especially in the aftertaste.
3. Textural Sweetness
In some cases, the sweetness in coffee may be experienced as a soft, rounded mouthfeel rather than a direct sugary taste. This textural sweetness provides a balanced sensation on the palate, without being as overtly sweet as typical sugar. It often feels like a smooth, velvety sweetness that enhances the overall drinking experience, complementing the coffee’s other flavors without overpowering them.
The Final Word
Although we've discussed the sweetness in coffee, it's important to note that most of the sugars in coffee beans are broken down during the roasting process. Roasted coffee beans do not directly contain large amounts of sweetness! The sugars in coffee can be categorized into polysaccharides, disaccharides, and monosaccharides. Polysaccharides like cellulose are not sweet, while sucrose (a disaccharide) breaks down into monosaccharides (glucose and fructose) during roasting and participates in the Maillard and caramelization reactions.
Arabica green beans contain about 8% sucrose. During roasting, sugars undergo the Maillard reaction and caramelization, which reduces their quantity, especially sucrose. By the end of the roasting process, the sugar content in coffee beans is significantly reduced, and only a very small amount of reducing sugars (usually around 0.3%) remains.
From a taste perspective, roasted coffee beans do not directly present sweetness. If you want to experience the sweetness in coffee, it's best to try green coffee beans, as the sugar breakdown during roasting significantly diminishes the perceived sweetness.
The reason we perceive sweetness in a cup of coffee is largely due to the retronasal pathway in our sense of smell. There are two ways we detect odors: orthonasal olfaction (smelling through the nose, like floral scents) and retronasal olfaction (smelling through the back of the throat, from the mouth). When the aroma travels through the retronasal pathway, we often mix taste and smell, leading us to mistakenly perceive sweetness. In reality, the sweetness we experience in coffee is not due to a high sugar content, but because of the interaction between the coffee’s taste and aroma, which tricks our brain into perceiving sweetness.
