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Mano / Al's Sweet Spot Rule
« 於: 三月 27, 2007, 08:07:22 pm »
早年網際網路不太發達的時代，咖啡討論必須依附在美食論壇裡，直到1994.3.21有了alt.coffee的出現，咖啡人終於有了自己的園地。alt.coffee剛起步的時候，花了數年的時間來建立大家對於咖啡基礎認知的水平，但是那個階段裡所有的資訊面是仍在業者手中，而且是在較有歷史、規模較大的業者身上，雖然illy跟Schomer的叢書相繼問世，貢獻了一些觀念性與實務性的資訊，但也常見新興業者或玩家，因為基礎理論模糊，而充斥錯誤的解讀或過度延伸。所幸，有一些很雞婆的業界職人願意花時間上網，來替大家一步一步做概念紮根和導正，這其中不乏知名業者。
上週是Al's Sweet Spot Rule發表七週年，一些歐美知名職人都在blog或是各論壇回憶這段往事........
2000年的3月，一切都因為那時還很菜的Mark Prince轉貼了一篇報章花絮開始，討論從義大利espresso的標準定義，到Mark的義大利見聞，最後有人搬出Schomer書中的章節，話題突然轉到ristretto這個名詞上......正當大家開始有點霧煞煞，懷疑東懷疑西的時候，Al Critzer（曾任職illy USA、Cimbali）加入了這個討論串，他提供了一個經過業者大量測試的歸納結果，並且為ristretto做了註解。對他而言可能不感覺到什麼特殊意義，因為一般相信這並非他個人獨到的見解（他自己也說This info was passed on to me by Dr. illy and his disciples, so I guess it is an Italian way of thinking as well as the single most respected scientific mind in the field of espresso. ），他可能只是一個傳播資訊的好心人而已，但絕對是當時網路論壇的經典大事件。他告訴了一大堆有研究咖啡熱情，卻缺乏正確理論基礎的人，一個可以朗朗上口的口訣。他所講的那幾段話，之後這些年經過千錘百鍊，不但是歐美最有共識的espresso觀念，甚至後來幾乎所有能在網路上看到的萃取文獻都以此為藍本，被稱為：Al's Rule，『艾爾鐵則：甜蜜點公式』。
原文如下：
It seems that everyone's close, but pretty much all around it. As I was trained, the perfect espresso is 30ml in 30sec. That's assuming that all other factors are in line. For longer extractions, the contact time of water to coffee would have to be lessened so that undesirable elements associated with overextraction wouldn't be present in the cup. With shorter extractions, the water to coffee contact time would have to be increased to ensure that underextraction doesn't occur. This is accomplished by grind adjustment. A good rule of thumb I have developed is this: For every 5ml of espresso above 30ml, subtract 1 sec of extract time. By this formula 1 1/2oz (45ml) would require 27sec extraction, 2oz (60ml) would require 24sec, etc. The same holds true in reverse. This will find the sweet spot in espresso regardless of volume in the cup (within reasonable limits of .75oz to 2.5oz), as you are optimizing extraction to the desirable elements, maintaining the balance between under- and overextraction. For some reason, grinder adjustment and it's crucial impact on espresso is the most difficult concept to explain and grasp in all the trainings I do.
大意是
至於那個年代也有爭議的ristretto定義，Al Critzer也順便做了他的解釋：
As to ristretto. This a different drink altogether. If your grinder is set for regular espresso, and you choose to stop the pour at 25ml, this is simply an underextracted espresso. You haven't hit the sweet spot yet. The " restricted" part referred to as ristretto is not so much related to volume as it is to water flow through the coffee puck. The ristretto that has been used for cuppings is a 25ml cup in 30-35sec. This extraction intensifies the organoleptic perceptions of the eyes, nose, taste buds and upper pallate to better isolate the positive attributes of a given blend. Where the positives are accentuated, the negatives are exacerbated as well. The extractions are characterized by a very thin mouse's tail with rich, dark brown crema. Most people don't drink this as their everyday drink, but it is helpful in developing blends. If you customarily drink 25ml (or 50ml doubles), your grinder should be adjusted accordingly. Damn, I did it again....
Al Critzer當時在討論串裡與知名業者Dr. Joseph John（Josuma Coffee Company）的另一段對話也很經典：
Dr John,
you didn't mention if this was done with the single filter or double. I'm hoping it was with the single. I personally am of the opinion that any espresso (single) should not be less than 25ml. A 1/2 oz (15ml) espresso has proved impossible for me to make in any drinkable state.
這裡Al等於是重申了他的公式是在setting work的最初，採用single basket沖煮的數據來作為推算的依歸。也就是縱然你的店裡平時出杯都是使用double濾器，single濾器仍然是設定的基準。而他個人經驗看法中，任何espresso（指single）都不應該少於25cc。一杯15cc的espresso對他而言，是無法達到『可以喝』的狀態（drinkable這個字離好喝還很遙遠） ，這也等於對後來一些喜歡30cc double ristretto的人提前做出了忠告。
以上整個相關討論串，仍然可以在alt.coffee 找的到，Al Critzer當時用的ID為ACKC3380。
......................
延伸閱讀
Jeremy R. Thompson的 How Al's Rule Saved My Life
Jim Schulman的 'extraction space' of espresso
上週是Al's Sweet Spot Rule發表七週年，一些歐美知名職人都在blog或是各論壇回憶這段往事........
2000年的3月，一切都因為那時還很菜的Mark Prince轉貼了一篇報章花絮開始，討論從義大利espresso的標準定義，到Mark的義大利見聞，最後有人搬出Schomer書中的章節，話題突然轉到ristretto這個名詞上......正當大家開始有點霧煞煞，懷疑東懷疑西的時候，Al Critzer（曾任職illy USA、Cimbali）加入了這個討論串，他提供了一個經過業者大量測試的歸納結果，並且為ristretto做了註解。對他而言可能不感覺到什麼特殊意義，因為一般相信這並非他個人獨到的見解（他自己也說This info was passed on to me by Dr. illy and his disciples, so I guess it is an Italian way of thinking as well as the single most respected scientific mind in the field of espresso. ），他可能只是一個傳播資訊的好心人而已，但絕對是當時網路論壇的經典大事件。他告訴了一大堆有研究咖啡熱情，卻缺乏正確理論基礎的人，一個可以朗朗上口的口訣。他所講的那幾段話，之後這些年經過千錘百鍊，不但是歐美最有共識的espresso觀念，甚至後來幾乎所有能在網路上看到的萃取文獻都以此為藍本，被稱為：Al's Rule，『艾爾鐵則：甜蜜點公式』。
原文如下：
It seems that everyone's close, but pretty much all around it. As I was trained, the perfect espresso is 30ml in 30sec. That's assuming that all other factors are in line. For longer extractions, the contact time of water to coffee would have to be lessened so that undesirable elements associated with overextraction wouldn't be present in the cup. With shorter extractions, the water to coffee contact time would have to be increased to ensure that underextraction doesn't occur. This is accomplished by grind adjustment. A good rule of thumb I have developed is this: For every 5ml of espresso above 30ml, subtract 1 sec of extract time. By this formula 1 1/2oz (45ml) would require 27sec extraction, 2oz (60ml) would require 24sec, etc. The same holds true in reverse. This will find the sweet spot in espresso regardless of volume in the cup (within reasonable limits of .75oz to 2.5oz), as you are optimizing extraction to the desirable elements, maintaining the balance between under- and overextraction. For some reason, grinder adjustment and it's crucial impact on espresso is the most difficult concept to explain and grasp in all the trainings I do.
大意是
- 以30cc/ 30sec得到一杯完美的Espresso的結果為出發點。這二個數值當然視豆子而定，烘焙方式、烘焙度、配方比例的差異自然會導致基準點的變動。
- 萃取量與萃取時間互為反比：
當萃取量越多的時候，咖啡粉與熱水接觸的時間必須越短（避免過度萃取）
反之，當萃取量縮減，咖啡粉與水接觸時間要增加（避免萃取不足） - Al公式：每增加5cc的萃取量，萃取時間要減去1sec。反之，則要加上1sec。
例如，萃取量增加到45cc時，30-(45-30)÷5=27，萃取時間縮減為27sec。
萃取量60cc時，萃取時間變成24sec。 - 這個公式在0.75-2.5oz的Espresso合理限定內，都能迅速正確的獵取甜蜜點（Sweet Spot），有效地抓到令人滿意的成分，並維持過度萃取與萃取不足之間的恐怖平衡。
- 控制的方式以調整研磨粗細為主要手段。
至於那個年代也有爭議的ristretto定義，Al Critzer也順便做了他的解釋：
As to ristretto. This a different drink altogether. If your grinder is set for regular espresso, and you choose to stop the pour at 25ml, this is simply an underextracted espresso. You haven't hit the sweet spot yet. The " restricted" part referred to as ristretto is not so much related to volume as it is to water flow through the coffee puck. The ristretto that has been used for cuppings is a 25ml cup in 30-35sec. This extraction intensifies the organoleptic perceptions of the eyes, nose, taste buds and upper pallate to better isolate the positive attributes of a given blend. Where the positives are accentuated, the negatives are exacerbated as well. The extractions are characterized by a very thin mouse's tail with rich, dark brown crema. Most people don't drink this as their everyday drink, but it is helpful in developing blends. If you customarily drink 25ml (or 50ml doubles), your grinder should be adjusted accordingly. Damn, I did it again....
- ristretto是一種跟正常espresso截然不同的飲料
- 如果研磨不變，用正常的espresso流速，提早結束萃取，比如說原先的30sec/ 30cc流速下，只取25cc，這就是一杯萃取不足的成果，因為還沒到達甜蜜點
- 所謂的ristretto就是受限定的意思（restricted），習慣作法是25cc/ 30-35sec
- 所有感官上能察覺的感受，包括眼睛看到的、鼻子聞到的、舌頭嚐到的，不論是好的味道，或是壞的味道，都被加重呈現
- ristretto的表徵是老鼠尾巴特別細，加上更深褐色的crema
- 大多數人不會每天喝這種東西，但是有利於仍在發展中的blend
- 如果你就是習慣要喝ristretto的人，不管是25cc或是50cc，那你的研磨就要去對應調整。怎麼調整？一樣啊，Al' Rule重新來過吧
Al Critzer當時在討論串裡與知名業者Dr. Joseph John（Josuma Coffee Company）的另一段對話也很經典：
Dr John,
you didn't mention if this was done with the single filter or double. I'm hoping it was with the single. I personally am of the opinion that any espresso (single) should not be less than 25ml. A 1/2 oz (15ml) espresso has proved impossible for me to make in any drinkable state.
這裡Al等於是重申了他的公式是在setting work的最初，採用single basket沖煮的數據來作為推算的依歸。也就是縱然你的店裡平時出杯都是使用double濾器，single濾器仍然是設定的基準。而他個人經驗看法中，任何espresso（指single）都不應該少於25cc。一杯15cc的espresso對他而言，是無法達到『可以喝』的狀態（drinkable這個字離好喝還很遙遠） ，這也等於對後來一些喜歡30cc double ristretto的人提前做出了忠告。
以上整個相關討論串，仍然可以在alt.coffee 找的到，Al Critzer當時用的ID為ACKC3380。
......................
延伸閱讀
Jeremy R. Thompson的 How Al's Rule Saved My Life
Jim Schulman的 'extraction space' of espresso