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萃取不足（Under-extracted Coffee）

萃取不足是指沒有將咖啡粉中足夠多的風味物質溶解出來，咖啡粉中依然有大量物質沒有被萃取出來。咖啡粉中的物質原本可以被萃取出來更多，來平衡掉不好的風味。

在你的印象中也許你曾經喝到過萃取時間過短的Espresso，比如說一杯用時下流行的精品咖啡烘焙度做的Ristretto。它會有刺激的酸、不足的甜感，怪異的鹹味和令人失望的短暫餘韻——這四個特徵是萃取不足最明顯的信號。接下來我們從細節層面逐一探討一下。

Under-extracted Coffee

Under-extraction occurs when you haven’t taken enough flavour out of the coffee grinds. There’s still a lot left behind that could balance out the following undesirables.

Cast your mind to a shot of espresso that was far too short; a ristretto of a typical Specialty espresso roast. It’s sour, lacking sweetness, weirdly salty and has a disappointingly quick finish. These four things are the most obvious indicators of under-extraction. Let’s go through them in a little more detail.

尖酸（sourness）

尖酸（sourness）是一個微妙的存在，特別是我們總想在咖啡中尋求好的酸質（acidity）的時候。很多人問我“尖酸（sourness）和酸（acidity）是不是一回事？”其實這個問題也在情理之中，因爲在很多語言中“sourness”和“acidity”就是同一個詞“酸”。因此你可以想象得出這樣的情況會讓不同語言的杯測變得有多麼的不便。

This is a tricky one, especially with our desire for acidity in coffee. I hear lots of people ask “Aren’t sourness and acidity the same thing?” and it’s a very valid question; in a lot of languages ‘sourness’ is the same word as ‘acidity’. As you can imagine, this makes multilingual cuppings a little difficult.

爲了區別起見，我通常把“尖酸”（sourness）定義爲負面的。尖酸（sourness）是一個非常迅速和強烈的感受。它會迅速地讓你產生生理反應，你會噘起嘴脣，舌頭兩側會有強烈而又尖銳的感覺。尖酸（sourness）是一種讓人不愉悅的味覺感受。

To clear this up, I always define sourness as being negative. A sour flavour hits you quickly and aggressively. It creates an immediate physiological reaction, you might pucker your lips or it might feel electric or sharp on the sides of the tongue. Sourness is undesirable and distracting.

無論何時我討論酸（acidity），它既可能是好的也可能是不好的。更恰當地說，它是一個風味範疇同時包含了正面和負面的特性。舉個例子，“那杯咖啡的酸非常讓人愉悅”（That coffee’s acidity isdelightful）和“那杯咖啡的酸非常尖銳”（That coffee’s acidity isvery sour）這兩種說法對我來說都說得通。酸（Acidity）裏包含了尖酸（sour）/果汁般的酸（juicy）/明亮的酸（bright）/刺激的酸（tart）等諸多內容。關於酸（acidity）我還有很多很多內容可寫，不過本週的內容主要是關於萃取，酸的話題姑且打住。

Whenever I talk about acidity it can be either good or bad. It’s more of a category of flavour than a positive or negative attribute. Example: “That coffee’s acidity is delightful” or “That coffee’s acidity is very sour” are both logical to me. Acidity is the umbrella under which lies all sour/juicy/bright/tart things. I could write volumes about acidity, but this week is all about extraction. Back to it.

缺少甜感（Lacking Sweetness）

在我看來，咖啡風味裏最重要的一個方面就是它的“甜感”。甜感即是奧義。你可曾聽過有人抱怨過“這杯 espresso太甜了”？你儘可好好想一想。我深信我們應該始終追尋甜感。它是我所追求的終極目標，想要實現是非常困難的，不過一旦你達到你將獲得超乎想象的回報。萃取不足是沒有甜感的，且與之相去甚遠。萃取不足總是會留下一些空洞的感覺讓你無法滿足，喝了一杯後會覺得“遠遠不夠”。缺乏甜感的一個好處就是它會使尖酸（sourness）更加容易辨識，從而使萃取不足更容易被發現。

Lacking Sweetness -
In my opinion, the most important aspect to a coffee's flavour is its sweetness. Sweetness is the best. Have you ever heard someone say 'this espresso is too sweet!'? Think about that for a second. I strongly believe that we should always be chasing sweetness. It’s my holy grail: something that’s really difficult to find and stupendously rewarding once you get it. Under-extraction isn't sweet. It's far from it. It almost always displays an emptiness that leaves you with an unsatisfying 'I-want-more' feeling after drinking. The good thing about this lack of sweetness is that it also accentuates the sourness, making under-extraction much more obvious.

鹹（Salty）

很多人也許都不太認同這個觀點，但我一定會據理力爭：“萃取不足的咖啡是會鹹的”。這種鹹不是那種“抱歉我不小心放了鹽”的鹹，萃取不足的咖啡總是會帶有鹹鹹的觸感和味覺。從口腔觸覺的角度來說，這種咸和鹼性溶劑會帶來的滑膩感很相似。（千萬別爲了證實這點去試喝氨水。相信我就好）

Salty -
Not everyone agrees with me here, but I’ll argue til I’m red in the face that under-extracted coffee is salty. It’s not quite ‘sorry I added table salt’ salty, but under-extracted coffee almost always has the mouthfeel and/or taste of saltiness. From a tactile point of view, it’s kind of similar to the slipperiness you get from alkalinity (Don’t go and drink ammonia to learn this one. Just trust me).

#註釋--酸和鹽的溶解性比糖要來得高。這也就是爲什麼萃取不足的咖啡會是尖酸和鹹的—萃取時間不夠長無法讓糖類完全溶解出來。（歡迎指正）

#PocketScience - Acids and Salts are more soluble than Sugars. This is why an under-extracted coffee is sour and salty - the sugars haven’t had enough time or chances to dissolve completely just yet. [citation needed]

餘韻短暫（Quick Finish）

一杯理想萃取的咖啡餘韻會持續數分鐘（甚至數小時，如果你夠幸運的話）。這種回味就像你剛喫了一塊黑糖，或者是剛喫了一塊太妃糖一樣，非常美味！

一杯萃取不足的咖啡則無法提供這些回味。當咖啡液體被你喝下去後，一切旋即消失，你不會感受到多少令你愉悅的回味。吞嚥後，一切戛然而止，這種意猶未盡的體驗，真的不是那麼美妙。

A well extracted coffee has a finish that lingers for minutes (or hours if you're lucky). This finish can feel as though someone has left dark brown sugar on your tongue, or as though you've just finished a toffee. Yum!

An under-extracted coffee doesn't have this finish. Once you swallow, it disappears straight away. You're not left with any pleasant lingering sensation. It's an abrupt and unsatisfying end to your coffee experience. Less Yum.

當然會有其他一些風味表現也會揭示出萃取不足的情況，但以上四個方面是最爲顯著的。當你嚐到了這四個風味表現時，你可以確認你的咖啡存在着萃取不足的情況。

接下來，讓我們把注意力轉移到萃取之路的另一端——萃取過度。

There are other flavours that indicate under-extraction, but these four are certainly the most obvious. Whenever you taste them, be sure that some part of your coffee is under-extracted!

Let's now cast our attention to the opposite end of Extraction Street.