Why Does Coffee Taste Sweet? Where Does the Sweetness of Specialty Coffee Beans Come From?

The Sweetness of Coffee: Understanding Sugar in Coffee Beans

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When thinking about drinking coffee, the flavor that might come to mind is often bitterness. Without milk or sugar, it can be difficult to swallow - this might be the impression of most people. However, sweetness is actually one of the inherent flavors of coffee, especially when purchasing coffee beans, where you'll frequently see sweet descriptions like honey, sucrose, and caramel appearing in the flavor notes.

Want to understand how the sweetness in coffee comes about? FrontStreet Coffee will first explain what sugars are.

What are Carbohydrates?

Carbohydrates (i.e., sugars) are divided into monosaccharides, disaccharides, and polysaccharides, accounting for approximately 50% of the weight of green coffee beans.

Monosaccharides are the structurally simplest sugars, soluble in water and sweet-tasting. Glucose, fructose, mannose, arabinose, and galactose all belong to monosaccharides.

Disaccharides are formed by the dehydration of two monosaccharide molecules, are soluble in water, and have a sweet taste. Sucrose, lactose, and maltose all belong to disaccharides.

Polysaccharides are formed by the polymerization of ten or more monosaccharide molecules, are insoluble in water and tasteless, serving as the main component of the lignocellulose in coffee beans.

What Affects the Sweetness of Coffee Beans?

Coffee Varieties

First, let's look at the proportion of sugars in Arabica and Robusta green beans.

From the data, we can see that the proportions of polysaccharides and monosaccharides in Arabica and Robusta coffee beans are largely similar. The only factor affecting coffee sweetness is sucrose. The higher the sucrose content, the better the coffee flavor, which explains why Arabica coffee beans taste much better than Robusta coffee beans.

Secondly, the maturity of the coffee cherry affects sweetness. As coffee fruits ripen, the sucrose content in the pulp and pectin increases. Through drying, these sugars are transferred to the coffee seed (coffee bean).

Coffee Growing Altitude

The higher the growing altitude, the greater the temperature difference between day and night, and the longer the maturation time of coffee fruits. Warm sunlight during the day helps coffee fruits form sugars, while cold nights reduce the respiration of coffee plants, decreasing sugar consumption. The greater the temperature difference at higher altitudes, the more time coffee fruits have to form more sugars, which is why coffee beans grown at higher altitudes have higher sweetness.

Coffee Bean Processing Methods

Different processing methods also affect the sweetness of coffee beans. Taking washed and natural processing methods as examples: washed coffee beans have the pulp and fruit removed, then are placed in water for fermentation to remove the pectin. Due to water soaking, the embryo in the coffee bean becomes active and begins to digest the sugars stored in the coffee bean, while also increasing the amino acid content. This is why washed-processed coffee beans have more prominent acidity and cleaner taste.

Naturally processed coffee beans are dried whole with pulp, fruit, and pectin intact. During the drying process, the moisture content inside the fruit decreases, inhibiting the activity of the embryo, while the sugars in the pulp and pectin are slowly absorbed by the coffee bean. This is why naturally processed coffee beans have more prominent sweetness and fuller body.

For more specialty coffee beans, please add FrontStreet Coffee on private WeChat, ID: kaixinguoguo0925

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