The extraction of hand-brewed and espresso is insufficient, what is the taste of excessive extraction? What is over-extraction?

Be reasonable, although everyone's taste is different, but everyone can reach a consensus on the bad taste! As long as there is an unpleasant taste in the coffee, such as irritating, astringent, bitter, charred, etc., this cup of coffee will most likely be judged to be untasty.

When these flavors appear, people will speculate on the reasons, such as insufficient extraction or excessive extraction is that people get the most results after calculation! So, for the novice rookie, how to judge that the extraction of this cup of coffee is insufficient? Appropriate? Or excessive?

What is insufficient extraction? What is over-exquisite? In 1952, Dr. Lockhart and his team found that there were 30% soluble substances in a coffee bean, and different degrees of extraction of these substances could lead to a change in the taste of the final coffee. Then they immediately investigated the finding, which is to sample the coffee preference of the American people. After many careful verification, it is concluded that when the extraction rate of coffee is in the range of 18% to 22%, it will have the most popular taste! And this is what we now know as gold cup extraction! When the extraction rate of coffee is less than 18%, the cup of coffee will be classified as insufficient extraction; when the extraction rate is more than 22%, it will be classified as excessive extraction!

However, Qianjie does not recommend directly measuring the extraction rate to determine whether this cup of coffee is suitable for extraction. On the one hand, we are not having an academic discussion, and on the other hand, even within the scope of gold cup extraction, there will be an uncomfortable negative smell. Mainly, Qianjie this article is mainly aimed at the problems you will face when making your own coffee at home: "how to judge whether the extraction is appropriate or not"! Therefore, Qianjie is more recommended to distinguish whether coffee extraction is appropriate according to the flavor tasted.

So, what is the taste of under-extraction and over-extraction respectively? Although Qianjie has shared this passage many times, it still needs to be mentioned again, because only by understanding this paragraph can we understand the true meaning of underextraction / over-extraction: coffee beans are mainly divided into three kinds of flavor substances, sour substances, sweet substances, and bitter substances. Although they will be released together at the beginning of extraction, their release rates are completely different! Sour substances are released in large quantities in the front, sweet substances are released in the middle, and bitter substances are released in the latter! Coffee will have a very different taste because of the different amounts of these three substances.

The taste of underextracted coffee will generally tilt to the sour end, with uncomfortable irritation, or other obvious negative taste! Of course, it can also be taste. Such as acetic acid, acidity, etc., are the most common negative manifestations in underextracted coffee; secondly, after drinking, there is almost no aftertaste, if so, it is likely to have the same astringency as eating immature fruit. And it may also have a more obvious salty taste! The salty taste of coffee always exists, but when the extraction is appropriate, it will be covered by sour, sweet, bitter and other flavors. In the case of insufficient extraction, the taste that can cover the salty taste is much less, so it can stand out!

And over-extracted coffee will have a more prominent and obvious feeling. When you drink in the coffee bitter, bitterness and other more prominent bitter taste, you will know: this cup of coffee is too good! Because of the over-extraction, it is to extract a lot of bitter substances from the coffee. Although there are some bitter substances in a cup of coffee with normal extraction, it is not so easy to detect because it is relatively small.

But when the extraction enters the latter stage, the bitter substance will begin to be released in large quantities, which will break the balance of taste, and the whole cup of coffee will tilt to the bitter end. In addition to the bitter taste, this cup of coffee will also have negative feelings such as dryness and emptiness. Dryness is mainly due to the fact that polyphenols bind to proteins in saliva and give rise to a rough taste, while the void is about the heavy, boring performance of coffee, which does not have any layering and does not stir up any waves in the taste buds.

So, what should be improved after the emergence of these two situations? The lack of extraction is mainly due to the fact that the brewing time is too fast, resulting in the fact that the water does not fully dissolve the substances in the coffee particles, while the excessive extraction is due to the fact that the boiling time is too long, causing the water to extract all the substances that should not be extracted.

Therefore, when this happens, we only need to control the rhythm of brewing (brewing method), or by adjusting the degree of grinding, water temperature and other extraction strength to correct the insufficient / excessive extraction, so that we can flush out the right taste of coffee!

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