How to judge whether a cup of coffee is good or bad? What is the measure?

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Underextracted coffee

Insufficient extraction means that there are not enough coffee powder substances brought out by water, and there are many residual substances in coffee powder, which can increase the flavor of this cup of coffee.

Imagine a cup of espresso with a short extraction time, that is, a boutique Italian concentrated ristretto, with a smelly sour taste, a lack of sweetness, a strange salty taste and a disappointing finish. These four characteristics are obvious signs of insufficient extraction, let's take a closer look at the phenomenon of insufficient extraction.

Salty taste

At present, not everyone agrees with the author, but this part must insist that under-extracted coffee will be salty. This is not like "I'm sorry I added salt to the coffee" kind of salty, but underextracted coffee, almost always have the taste of the salty taste. From a tactile point of view, it's like being slippery in contact with alkaline food (please don't drink Amonia to feel the taste, believe me).

# Science Lecture-sour and salty tastes dissolve more easily than sweetness, which is why underextracted coffee has sour and salty tastes, and sweet substances do not have enough time or opportunity to dissolve completely.

Yu Yun is short.

The aftertaste of a well-extracted coffee can last for several minutes (or even a few hours of luck). It can be imagined that someone has put a piece of brown sugar on your tongue, or that you have just eaten a delicious taffy.

The underextracted coffee does not have this aftertaste. When you swallow the coffee, the flavor dissipates. There is no pleasant feeling left in your mouth, which makes you experience the short and unsatisfactory taste of this cup of coffee, which is bad and not delicious.

There are other bad feelings that represent insufficient extraction, but the above four items are more obvious and definite. Whenever you drink these properties, you can be sure that you are drinking coffee that is not sufficiently extracted. Over-extracted coffee, over-extracted coffee means to bring out too much soluble matter in the coffee, the result of this extraction is a bad flavor.

Imagine a cup of fine espresso with an extraction time of 40-50 seconds. Don't pretend you haven't tasted this exquisite coffee. This kind of coffee can be bitter and dry, which represents the most obvious feature of over-extracted coffee. Let's take a look at these characteristics again.

Bitter taste

We have all had bitter coffee. The over-extracted coffee is really bitter, and I don't want to have such a bitter taste unless I'm drinking Kimberly bitterness. Much of the bitterness comes from caffeine, but bitterness is also related to many other chemicals. Deep-roasted coffee will reach a charred state and form more bitter chemicals.

Astringent feeling

It is very uncomfortable to drink dry coffee in coffee, because the dryness is very strong and will last for a long time. This feeling is called astringency, just like you drink unsweetened black tea, new wine, overbrewed white wine. The astringency in wine comes from the polyphenol effect: these are chemicals that are easily found in plants, seeds and bark, and may also make coffee feel dry.

Polyphenols are bitter and bind to the proteins in your saliva. As most people know, polyphenols dry your tongue and produce a rustling or dry feeling in the mouth (this should not be confused with "crisp" or "dry" in wine. These adjectives indicate distinct acidity or low sweetness, not necessarily taste)