Introduction of common fermentation treatment methods of coffee beans differences in flavor characteristics of coffee treated with sun, water washing and honey

The three most common fermentation methods of coffee beans

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.

The three most common fermentation methods of coffee beans

The fermentation of beer

There is no doubt that beer is produced by fermentation, and the best-known formula for the fermentation of alcohol is that sugars produce alcohol and carbon dioxide by yeast. But in fact, the fermentation of beer is much more than alcohol. All kinds of flavors that people like and dislike need to be precisely controlled by the fermentation environment and state in order to produce more good flavors and less bad flavors.

Whether making noodles or making wine, it depends on the life activities of microorganisms under aerobic or anaerobic conditions to prepare microbial bacteria themselves, or their direct metabolites or secondary metabolites.

Interestingly, in the process of beer fermentation, the late yeast is still crying for food, at this time the fermentable sugar may have been exhausted, a variety of fermentation metabolites by-products will become yeast food.

Yeast that works like a beast in beer

At this time, winemakers control the bad taste to be eaten more, and the good taste to be eaten less, which becomes subtraction from addition. This is the main reason why beer needs ripening and diacetyl reduction, and some bottled beers taste better after a long time, because the bad taste is getting less and less, and the quality of the wine becomes clearer and cleaner.

The fermentation of coffee

Different biological changes take place in the natural fermentation of coffee. Yeast produces enzymes and lactic acid bacteria decompose the sugar in coffee pectin. Lipids, proteins and acids in sugars are degraded and converted into alkyd (alcohol acidic acids). The smell, color and pH of coffee will change, and so will the pectin composition of coffee.

The core of treatment is fermentation.

In the process of fermentation, different substances are involved (coffee peel, coffee pulp, coffee pectin, bacteria species, bacteria distribution), different environments (water and water, oxygen and oxygen, PH environment, etc.). Different drying methods and processes (container material, natural sun, drying equipment, turning times, etc.), resulting in different post-processing flavor and taste.

The basic process of coffee is coffee planting-> raw bean treatment-> cooked bean roasting-> coffee brewing. However, in this process of raw bean treatment, all kinds of treatment methods are inextricably related to fermentation.

There are many fermentation methods, two of which require special attention: dry fermentation (dry fermentation) and wet fermentation (wet fermentation).

Dry fermentation Dry fermentation and its Flavor characteristics

Put the coffee with pulp and pectin on the surface in a concrete fermentation tank. Dry fermentation helps to improve the sweetness, chocolate and fruit flavor characteristics of the coffee. Dry fermentation is also accompanied by a challenge: controlling the temperature. Temperature affects the degree of fermentation, poor temperature control will have a negative impact on the consistency and flavor of coffee.

Wet fermentation Wet fermentation and its Flavor characteristics

Wet fermentation is sometimes called "double washing" double washed, "double fermentation" double fermented, "Kenyan water washing", and so on. This treatment is common in East Africa and can improve purity.

"after removing the peel and pulp of the coffee, we soak the coffee with parchment in water, which prolongs the fermentation time and produces a soft mellow thickness, complex acidity, and more subtle flavor.

Natural Process

Solarization method

Sun-Dried or Natural full sun exposure

As the name implies, sun-drying means that coffee fruits are completely dried by the sun.

Sun treatment is the simplest and cheapest traditional method in coffee bean processing. During processing, the harvested fruit should be spread on cement floor, brick floor or straw mat, viaduct bed and sun bed should be put in the sun, and rake is often used to prevent fermentation. If it rains or the temperature drops, the fruit must be covered to prevent damage.

After about treatment, the water content of each fruit will decrease to about 12%.

Honey Process

Honey treatment method

Honey (Miel) Processing honey treatment

Peel and pulp are removed by machine and pectin is retained for sun drying.

White Honey honey 80% mae 90% pectin was removed.

Yellow Honey yellow honey retains 50% pectin and has no fermentation. Receive the most light and dry for about 8 days

Red Honey red honey removes 25% pectin and has no fermentation. The sun lasts about 12 days, and a sunshade may also be used in the process.

Black Honey black honey basically retains all pectin and dries at a slightly higher temperature at low altitude. It is covered with slight fermentation in the first 24 hours, and then the drying process is transferred to an African drying bed for drying.

Gold Honey Jinmi basically retains all pectin, drying at low temperature at high altitude and prolonging the drying time.

In individual estates, the treatment of individual batches will be different.

Washed process

Washing method

Washed: semi-washed Semi-Wash and full-washed Full-wash.

The traditional water treatment is used to treat freshly picked coffee beans. The flesh of the coffee is peeled off immediately, and the shorter the interval is, the better. Then the coffee beans are soaked in water for 12-36 hours. This process softens its skin so that it can be washed off easily. Coffee beans are then sorted and dried in the sun.

The final product of both methods is: raw coffee beans with parchment.

Main difference: remove pectin directly by machine or through fermentation tank to remove pectin layer.

Semi-washed: after peeling and pulping, the coffee fruit does not go through the fermentation tank, but through a special pectin removal machine to remove pectin.

Full water washing: after removing the peel and pulp of the coffee fruit, enter the fermentation tank and remove the pectin layer after 1-2 days of fermentation (the time varies according to the temperature and humidity of the site). There are different ways of enzyme and no enzyme.

Ethiopian water washing: belongs to the traditional wet fermentation treatment. The coffee cherries are washed, peeled and introduced into the fermentation tank to ferment with water below the water level of the fruit, rinse, soak in a clean sink for one night, and dry in the greenhouse the next day. Fermentation with water for up to three days, need a lot of clean water, need to monitor the process of PH should not be lower than four or five.

Kenyan washing: the famous K72 mode. Coffee cherry wash, peel, dry fermentation 24 hours, wash, dry fermentation again 24 hours, wash, dry fermentation again 24 hours, cycle treatment, reach 72 hours fermentation, after washing, soak the sink for one night, and start drying the next day.