The difference between the flavor characteristics of sun-cured coffee and water-washed coffee which is more sour by sun-washing?

Usually when we buy coffee beans, if we want to be sweeter, we will prefer sun-treated coffee to washing. Is tanned coffee really sweeter than washed coffee? Where does sweetness come from?

Qianjie's previous articles have explained that the "sweetness" in our coffee mainly comes from the amount of carbohydrates (sugars) in raw beans. The higher the sucrose content, the better the sweetness. The content of sucrose depends on the growth factors such as the variety of coffee, the maturity of berries and the altitude of planting, and is not affected by the treatment of raw beans.

In 1963, Coffee processing Technology (Coffee Processing Technology) written by Michael Sivetz, a well-known American coffee chemist, and a study by food chemist Alan Varnam in 1994 both pointed out that the ingredients derived from the sun method were obviously different from the water washing method, and the fat, sugar and acid content of sun-dried beans were higher than those of water-washed beans.

The structure of a coffee fruit can be divided into pericarp, pulp, pectin, sheepskin, silver skin, seed, we drink coffee is the innermost seed.

When washing, you need to peel and remove the meat by machine before drying, leaving the seed and a layer of sticky pectin to be thrown into the sink to allow the acid produced by fermentation to decompose the pectin. Soaked in water, the coffee bean mistakenly thinks it has come to a suitable growth environment, so it starts to sprout, prompting some chemical changes in the beans and consuming the monosaccharides (fructose and glucose) in the coffee, resulting in a decrease in sugar content in raw coffee beans and an increase in some amino acids. Amino acids are the antecedents of coffee to form a complex aroma.

During the sun treatment, the beans in the coffee are wrapped in the pulp for drying, the plant hormones and water in the pulp inhibit the germination of the seeds, the metabolism of the new town in the raw beans will stop completely, and the sugar content is certainly more than that of the washed coffee.

Compared with water washing, the fermentation time of sun treatment was longer, and the reaction degree between bacteria and pulp was higher. When the fruit begins to ferment, microorganisms produce more volatile compounds, especially esters. Although most sugars are destroyed during baking, these compounds are converted into another form of aromatic compounds during caramelization. It is also these aromatic substances that provide more floral aromas and fermented aromas of tropical fruits for ripe coffee beans, such as esters, which make sun-cured coffee wider and sweeter.

Although the sun method can preserve more monosaccharides, it does not mean that sun beans are necessarily sweeter than washed beans. Coffee beans are dehydrated and dried when the sugar content is the highest. If the fruit is overfermented to produce rotten acid, or if the fermentation process is not properly controlled, it is easy to release bad sour or bitter taste after brewing, which affects the sweetness of the final coffee.

In addition to the way of treatment, the difference between roasting and extraction can also affect the sweetness of coffee.

Roasting sublimates the sugar content of coffee, and professional roasters know how to reach the highest sweet spot and retain the acidity of the coffee, so that the sweet, sour and bitter aroma of coffee interact and ultimately influence the overall impression when we taste it. Therefore, under the reasonable roasting control, we may still drink washed coffee which is sweeter than sun-cured coffee.

A coffee bean that has reached a sweet spot in baking will also affect the final taste performance because of the difference in the configuration of cooking parameters. Acid will neutralize sweetness, bitterness will suppress sweetness, coffee that is too sour or too bitter will affect the sweet feeling in the mouth.

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