What is double fermentation? What's the difference between dry fermentation and wet fermentation?

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The word "fermentation" in life is often reminiscent of flour making cakes, Youtiao, steamed buns, steamed buns, or moldy food products. Fermentation has been so widely used in our daily life that we enjoy a wide variety of delicious fermented food. Huizhou hairy tofu, French wine, homemade pickled radish, northeast sauerkraut pork, canned Swedish herring, everyone knows it's fermented.

But in English, Fermentation is derived from the Latin fervere, which originally means "tumbling". It describes the phenomenon that yeast foams slightly or violently resembles boiling when yeast acts on grape juice or wort.

Simply put, fermentation is the process by which sugars and starches break down into acids or alcohol. Let's delve deeper. Sasa says yeast and bacteria are important for fermentation.

Yeast fermentation, called Saccharomyces cerevisiae, is a natural wild yeast that is also found in grapes, cocoa beans and other fruits. It is currently used in wine making, cocoa bean processing and coffee processing. "

And the strain is lactic acid bacteria.

During the natural fermentation of coffee, different biodegradation procedures take place, and enzymes produced by yeasts and bacteria begin to decompose the sugar in the pectin layer. Sugar breaks down lipids, proteins and acids and converts them into alkyd, which changes the smell, color, pH and composition of the pectin layer of coffee beans.

Sasa also said that there are many different fermentation methods in the world, but they are mainly divided into dry fermentation and wet fermentation.

Dry fermentation and its flavor

"after we remove the pulp, we put the coffee with endocarp in the fermentation tank, and the fermentation promotes the sweetness, chocolate and fruit flavor of the coffee." but one of the challenges of fermentation is temperature control.

Since temperature can affect the degree of fermentation, it will also negatively affect the stability and flavor of the process.

Wet fermentation and its flavor

You may have heard someone describe wet fermentation as double washing, double fermentation, Kenyan washing, etc., which is common in East African countries and is famous for its clean and clear flavor, but Sasa describes this treatment as adding flavor to the cup.

"when we remove the pulp and put the coffee with endocarp into the water, the water will help prolong the fermentation time, resulting in a softer mellow thickness, rich acidity and more elegant flavor characteristics of the coffee."

Of course, this does not mean that the treatment is not challenging. Sasa mentioned that temperature and water quality can also affect the results.

Sasa: "A few years ago, I did an experiment with Raul Riviera, the owner of Santa Rosa in El Salvador. We used Rain Water instead of spring water to ferment. Rain Water would absorb a lot of fruit flavor and sugar from the coffee fruit. As a result, the cup test score was reduced by five points. The coffee tasted insipid and had no distinct flavor. The effects of the water used for fermentation still need to be studied. "