Why is coffee sweet? Where does the sweetness of boutique coffee beans come from?

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When it comes to drinking coffee, the taste that flashes through your mind may be very bitter. Without milk or sugar, you can't taste it at all. This may be the impression of most people. But in fact, sweetness is one of the flavors of coffee, especially when buying coffee beans, we will often see sweet descriptions such as honey, sucrose and caramel in the flavor bar.

If you want to understand how the sweetness in coffee comes from, first of all, front street coffee has to talk about what sugar is.

What is sugar?

Carbohydrates (sugars) are divided into monosaccharides, disaccharides and polysaccharides, accounting for about 50% of the weight of raw coffee beans.

Monosaccharides are the simplest sugars, soluble in water and sweet. Glucose, fructose, mannose, arabinose and galactose are all monosaccharides.

Disaccharides are formed by dehydration of two monosaccharide molecules, soluble in water and sweet. Sucrose, lactose and maltose are all disaccharides.

Polysaccharides, which are polymerized by more than ten monosaccharide molecules, are insoluble in water and have no sweet taste. they are the main components of lignocellulose in coffee beans.

What affects the sweetness of coffee beans?

Coffee variety

Let's take a look at the percentage of sugars in an Arabica and Robusta raw bean.

Arabica (raw bean)

Robusta (raw bean)

Polysaccharides

43% Mutual 45%

46.9% Mutual 48.3%

Monosaccharide

0.2% Mutual 0.5%

0.2% Mutual 0.5%

Disaccharide (sucrose)

6% 9%

3% Murray 5%

It can be seen from the data that the percentages of polysaccharides and monosaccharides of Arabica coffee beans and robusta coffee beans are more or less the same, and the only thing that can affect the sweetness of coffee is sucrose. The higher the sugar content, the better the flavor of the coffee, which explains why Arabica coffee beans taste much better than robista coffee beans.

The second is the maturity of coffee berries. As the coffee fruit ripens, the sucrose content in the pulp and pectin parts will be higher, and by drying, the sugar will be transformed into the coffee core (coffee beans).

Coffee planting altitude

The higher the altitude, the greater the temperature difference between day and night, and the ripening time of coffee fruit will be prolonged. The warm sunlight during the day helps coffee fruits form sugar, while the cold at night reduces the respiration of coffee plants and reduces sugar consumption. The higher the altitude, the greater the temperature difference, the coffee fruit has a lot of time to form more sugar, so this is why the higher the altitude, the sweeter the coffee beans.

Coffee bean treatment

Different treatments can also affect the sweetness of coffee beans. Take water washing treatment and sun treatment as examples. Washed coffee beans remove the peel and pulp and then put them into water for fermentation to remove pectin. Because of soaking in water, the germs of coffee beans are ready to digest the sugars stored in coffee beans and increase the content of amino acids in coffee beans, which is why the sour taste of washed coffee beans is more obvious and the taste is cleaner.

Sun-treated coffee beans are the whole peeled pulp pectin for sun-drying. in the process of drying, the moisture in the fruit will become less and less, inhibiting the imminent movement of the germ, and at the same time, the sugar in the pulp pectin will be slowly absorbed by the coffee beans. this is why the sun-treated coffee beans are sweeter and fuller.

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