What is anaerobic fermentation in coffee treatment? Do anaerobic fermented beans taste good?

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Today, Qianjie Coffee introduces what is anaerobic fermentation?

Anaerobic fermentation is not a new term in fermented food. Anaerobic bacteria are involved in the fermentation process of kimchi and wine. Now that we know that the post-processing of coffee beans is a fermentation process, the rest is the principle of fermentation.

Traditional sun exposure, water washing and honey treatment are mostly exposed to an open environment, so the existing bacteria that interact with them are usually oxygen-loving bacteria, such as photosynthetic bacteria and yeasts (yeast is facultative or oxygen-free). Anaerobic fermentation naturally uses the operating mechanism of anaerobic bacteria, such as lactic acid bacteria, filamentous bacteria and yeasts.

To produce anaerobic fermentation is not to throw any bacteria to the coffee beans, but to create an environment for the coffee beans to ferment, so it is usually necessary

1. Closed enclosed space: if you don't need to borrow other flavors, you should use easy-to-clean storage space such as white iron or stainless steel, but white iron is too expensive. (I don't think I can use a gasoline can.)

two。 Control the temperature and grasp the right time

3. Enough high-quality coffee beans (with a certain sweetness)

As for the need for peeling, dry treatment or wet treatment, this is the trade secret of the landowners, and there is no unified standard.

It is also logically reasonable, because a large part of the role of anaerobic fermentation falls on microbial species, and lactic acid bacteria convert glucose into the sweet and sour feeling of lactic acid under the action of no oxygen.

The chemical formula for the reaction of lactic acid bacteria with sugar is as follows:

C6H12O6 (glucose etc.) + 2 ADP+2 phosphate → 2 lactic acid (lactic acid) + 2 ATP

However, in an anaerobic environment, yeast undergoes anaerobic fermentation to convert glucose into alcohol (ethanol):

C6H12O6 → 2C2H5OH (ethanol) + 2CO2+2ATP

Alcohol is then converted into esters with other organic acids (such as lactic acid mentioned earlier), which is an important source of flavor for coffee fruits. So the anaerobic fermented coffee bean alcohol is thicker and has a wine-like mellow feeling, but the sweetness or fruit flavor is better than honey treatment.

Some handlers will keep the coffee beans from the pulp for anaerobic treatment, but the risk is that the yeast will convert glucose into alcohol, there is too much pulp in the glucose content must be very high, if there is not enough organic acid can not be fully converted into alcohol, there will be too strong fermented wine flavor, too much wine taste is terrible.