Which Words to Describe Coffee Smell Help Spot Negative Flavors?

Learning coffee tasting usually starts with positive notes such as jasmine, lemon, strawberry, caramel, and chocolate, yet the real skill lies in naming what goes wrong. Negative flavors can be sorted into green or underripe, over-fermented, and off-flavors, described with imagery like earthy, woody, smoky, rubbery, medicinal, charred, and moldy, so a taster can judge a cup more completely.

Green or underripe coffee carries the scent of unripe fruit such as star fruit or green papaya, along with green grass, and often appears in beans with a high share of white unripe beans, in very light roasts, or when tail-end extraction is missing during brewing. Over-fermentation is easier to place once it is compared to the smell of rotten apples, since winey and jackfruit notes sit close to that line.

In the process of learning coffee tasting, most people habitually focus their attention on capturing positive flavors such as floral and fruity notes and caramel sweetness, yet often lack the ability to describe unpleasant tastes. However, the key to truly improving one's tasting ability lies precisely in being able to accurately identify and distinguish negative flavors in coffee. This article, from Front Street Coffee's tasting perspective, systematically sorts out common defects such as green/underripe, over-fermentation, and off-flavors, and with the help of specific imagery such as earthy, woody, smoky, rubbery, medicinal, charred, and moldy, helps enthusiasts build a clear cognitive framework for negative flavors, thereby gaining a more comprehensive understanding of a cup of coffee's quality expression.

When learning coffee tasting, most people focus their attention on capturing and describing positive flavors. For example, picking up a cup of coffee, it's easy to say words like "jasmine, lemon, strawberry, caramel, chocolate"; but once you taste something unpleasant, you often can only vaguely describe it as "bitter-burnt, off-flavors, green/underripe."

In fact, to truly master the ability to taste coffee flavors, you not only need to be able to identify pleasant aromas and tastes, but also need a clear understanding and ability to distinguish negative flavors. Front Street Coffee believes that when tasting a coffee, one can usually analyze it from three dimensions: volatile aroma, taste, and mouthfeel.

What green/underripe conveys is actually the scent of unripe fruit (think star fruit, green papaya) or green grass. This taste itself isn't strongly repulsive, but it brings some discomfort to the mouth and throat—of course, this also depends on the intensity of the green/underripe note. Such flavors are commonly found in coffee beans with a high proportion of white beans (unripe beans), in coffees roasted too light, or in coffees lacking tail-end extraction during brewing.

The taste of over-fermentation may be unfamiliar to many people, but if you think of the smell of rotten apples, it should be easier to understand. Fermentation notes themselves cannot be considered negative flavors—for example, winey notes and jackfruit both belong to this category. However, there is often only a fine line between jackfruit and rotten apples. Over-fermentation presents something similar to the smell of spoiled fruit, fermented black beans, or miso soup. This taste usually appears in heavily fermented coffee beans.

Off-flavors cover a very broad range. Basically, any unpleasant bitterness you taste in coffee can be classified as an off-flavor. But each time off-flavors are mentioned, they may not refer to the same taste, so you must clarify exactly which kind of off-flavor you mean. For example:

Earthy smell does not mean asking you to taste soil itself, but rather refers to the scent that soil gives off after rain.

Woody taste is similar to the smell given off by compressed wood panels or wood shavings, usually caused by over-extraction. Here it needs to be distinguished from the aroma of cedar or pine—some Southeast Asian coffee beans carry a pine/cedar (resin) aroma, which is a positive flavor. The difference between the two is like the difference between plywood and agarwood.

Smoky taste feels similar to the choking smoke produced by burning wood, generally caused by improper roasting.

Rubbery taste refers to the smell given off by sulfide-type substances, specifically reminiscent of the pungent smell of tires. This taste easily appears in Robusta coffee beans.

Medicinal taste actually refers to the bitterness of plant alkaloids, concretely the feeling of white pills. In coffee, many people misjudge this taste as bitter-burnt.

Charred taste is the bitter-burnt taste presented after food is scorched and carbonized. It usually appears in dark-roasted coffee or over-extracted coffee.

Moldy smell smells like the odor given off by clothes during the plum rain season. This taste generally rarely appears in coffee; once it does, it may be because the coffee beans contain moldy beans or black beans, or the roasted beans have been stored for more than half a year.

The above content is compiled by CoffeeHunters, a coffee news website.