About coffee aroma / defective smell

Defective smell

Aromatic Taint

There is no gold, and so is coffee. In addition to the natural and fresh aroma of flowers and fruits, sweet caramel, coffee will also have a bad smell, which is what we are going to talk about today.

Before a cup of coffee is presented to guests, it often goes through many processes: picking, processing, transportation and storage of raw beans. Due to the complexity of the production chain and defective flavor, it may be produced in a certain step. Improper management of coffee beans leads to a decline in quality and even defective beans, affecting the drinking experience.

For healthy coffee beans, due to different treatment methods, the bean color should be blue-green, light green or yellow-green. If coffee beans have different colors, spots and gaps, it is the performance of defective beans.

Black bean

All black beans and half black beans

Cause of formation

The reasons for the formation are complicated, mainly caused by coffee tree disease, caused by an organic pathogen Colletotrichum coffeanum, which originated in Africa, excessive washing and sun fermentation, coffee fruit pollution, unripe beans dried at high temperature and so on.

Influence

Contains Geosmin, which can produce miscellaneous soil smell, over-fermented sour smell, bad smell, bitter taste and potion smell, and even affect health.

Sour bean

Sour beans and semi-sour beans

Cause of formation

The main reason is excessive fermentation, fruit ripening or ripe damaged fruit on the ground; fermentation pool pollution, will also produce sour beans.

Influence

The sour smell of overfermentation, the skin and interior turn dark brown.

Moth-eaten bean

Light worms and serious borers

Cause of formation

Coffee pests drill into and lay eggs in coffee beans during the planting of coffee trees.

Influence

The bean surface often has small black pores in the shape of bruises, resulting in dirty, sour, fungal and phenolic odors.

Moldy bean

Cause of formation

The storage environment is moist, breeds mold at a certain temperature and humidity, and infects other coffee beans; contaminated during fermentation.

Influence

Everlasting mildew soil flavor, phenol flavor.

Unripe bean

Reason

Inappropriate picking; late-maturing varieties grown at high altitudes.

Influence

Produce the smell of grass and straw.

In addition to the above defective beans, there are shell beans, floating beans, shell beans, condensed beans and so on, which will affect the quality and flavor of coffee.

The content of precursors in coffee beans is significantly reduced due to oxidation or fungal infection, but natural bitter substances such as "chlorogenic acid" and "caffeine" are not reduced. What is more, it will produce dioxy butyraldehyde and trioxy butyraldehyde, resulting in sour smell and pungent potion and leather smell. The group of defects in the fragrance bottle has the following odors:

Native Earth

Rice straw Straw

Coffee pulp Coffee pulp

Leather Leather

Fragrant rice Basmati rice

Cooked beef Cooked beef

Smoke Smoke

Potion flavor Medicinal

Rubber Rubber

So far, we have introduced four groups in 36 fragrant bottles: Meena group, caramel group, dry distillation group and defect group. But the flavor of coffee is much more than that. The overall flavor of a cup of coffee is determined by its volatile aroma, water-soluble taste and mellow thickness, which requires us to use the three senses of smell, taste and touch to appreciate it.