Espresso requires the finest grind of any brew method besides Turkish coffee, which means your espresso grinder is working a lot harder than your filter grinder to process the same amount of coffee. When you consider that most specialty coffee shops go through more espresso than filter, it’s clear who your workhorse is. You need an espresso grinder that can take some abuse. Espresso grinders can be divided into two camps: conical burr grinders and flat burr grinders. Just like Ford vs. Chevy or Tupac vs. Biggie, both camps have their advocates and detractors.

義式磨豆機
濃縮咖啡相較其他沖煮法需要最精細的研磨（土耳其咖啡除外），這表示若要得到相同量的咖啡，濃縮咖啡要比過濾咖啡的研磨負荷重許多。當精品咖啡店推出的濃縮比過濾咖啡多時，磨豆機的負荷會很重，因此更需要一台濃縮咖啡用的義式磨豆機。（咖啡苗認為，一個小時如要製作60杯以上的拿鐵，如一杯粉量是16克，一個小時就是960克，約莫一公斤的咖啡粉，刀盤的連續操作穩定度就很重要。）
義式磨豆機可分為兩種：錐刀型磨豆機、平刀型磨豆機。這兩者就像福特汽車對比雪弗蘭，都有各自的擁戴者。

Conical Burrs
Conical burr grinders, like the ubiquitous Mazzer Robur E and Compak K10, have been the industry standard for years. As the name implies, conical burrs are cone-shaped, with a male and female piece. This allows more efficient, faster grinding than with flat burrs.
錐刀型磨豆機
錐刀型磨豆機多年來就像是咖啡的業界標準：無處不在的Mazzer Robur和Compak K10。錐刀型顧名思義就是錐狀、以一公一母的形式組成，這讓錐刀型的磨豆速率比平刀型更高。

Conical burr grinders produce what is called a bimodal particle size distribution. This means if you looked at the coffee grounds under a microscope and grouped like-sized particles together, you would be predominately left with two groups: one composed of smaller particles; and one, larger. The smaller particles restrict the flow of water through the coffee bed, giving the larger particles more time to saturate. A conventional espresso recipe is dependent on this slower flow rate.
錐刀型磨豆機構成了雙峰的粒徑分布，當你在顯微鏡下觀看研磨出的咖啡粉，相似粒徑的粉會集結再一起，主要分為較小與較大的顆粒，較小的顆粒限制了水通過咖啡粉的流速，使較大的顆粒有更多時間達到飽和，傳統的濃縮咖啡配方依賴這樣的方式來減緩流速。
 

A bimodal grind from conical burrs tends to produce a stronger shot of espresso with more body, something their advocates appreciate. Proponents of flat burr grinders point to the uneven extraction that comes from having two different groups of particle sizes. Different particle sizes will saturate at different rates, leading to differences in extraction percentages between the various particles.

錐型造成雙峰分布的研磨結果，將使煮出來的濃縮咖啡更飽和、濃郁。平刀型磨豆機的擁戴者則指出這些雙峰分布的顆粒大小，顆粒的大小會產生不同的飽和速度，而不同的飽和速度決定了其萃取率。

Flat Burrs
Recent years have seen a decided shift toward flat burr grinders. True to their name, flat burrs feature two matching burrs that set flush against each other. This creates a more uniform particle size distribution, allowing the barista to extract more of the coffee without worrying about bitter, dry flavors drawn from finer particles. The lack of flow restriction with flat burr grinders, because there are fewer fine grinds, however, forces the baristas to either grind finer (which has its limits) or pull longer shots. The move to much larger shots was made possible by these grinders, and if you’re hoping to break out of SCAA parameters for your espressos, you’ll need a flat burr grinder to do it.
平刀型磨豆機
近年來大家對平刀型磨豆機有改觀，平刀型就是兩個相符的磨盤組成，彼此不干擾運作，這形成了更均勻的粒徑分佈，使咖啡師萃取咖啡時不必擔心會從較細顆粒的咖啡粉，萃取出苦澀的味道。平刀型磨豆機因為有較少的精細研磨，而無法控制流速，但是這也迫使咖啡師將研磨刻度調細（有它的極限），或拉長沖煮時間。使用這些磨豆機讓製作量大的濃縮更駕輕就熟，而如果你希望跳脫出SCAA的濃縮參數，你需要一台平刀型磨豆機來做到。

The popularization of flat burr grinders can be attributed to Matt Perger’s 2013 World Barista Championship routine, in which he shocked the coffee world by preparing all of his beverages with a Mahlkönig EK 43. Originally designed as a spice grinder, the EK 43 features gigantic ninety-eight millimeter steel burrs (Mazzer’s flat-burr machines have eighty-three millimeter burrs, for comparison). Those giant burrs help the EK 43 create its unrivaled tight particle size distribution.
平刀型磨豆機的發揚，源自於Matt Perger在2013年世界咖啡師大賽時，使用Mahlkönig EK 43磨豆機製作他的飲品（可參考Come True Coffee翻譯的EK43文章）。一開始EK43是發明用作香料研磨，98釐米的巨大鋼刀盤（Mazzer的平刀型磨豆機磨盤則為83釐米）。這巨大的刀盤幫助EK43創造出無出其右的粒徑分布。
 

Whether you opt for a fan or a heater, make sure your house espresso grinder has some sort of temperature regulation.
Espresso preparation with the EK 43, however, is cumbersome to say the least, which has opened the door for a new generation of espresso grinders to mimic the EK 43’s larger burrs but in a machine built for espresso preparation. One of the first companies to respond to this new demand was Nuova Simonelli with their Mythos series. Last year, Mahlkönig released the Peak, named for the visualization of a unimodal grind distribution, accomplished here with an eighty millimeter steel burr.
無論你選擇用風扇或是加熱器，都要確保義式磨豆機能調節溫度
用EK43製備濃縮咖啡很繁瑣，但這至少開啟模仿EK43大尺寸刀盤的新紀元，也闢建了用咖啡機製備濃縮咖啡的方式。第一個因應這新需求的公司是推出Mythos系列的Nuova Simonelli。2015年Mahlkönig發表Peak這台磨豆機，是以80釐米鋼刀盤的單峰粒徑分布而命名。
 

Espresso Grinder Problems
Whether or not you choose conical or flat burrs, practically all models of espresso grinders have two obstacles to overcome: temperature fluctuations and grind retention.
Friction generates heat, and grinding for espresso creates a lot of friction as the bean is broken down to a finer and finer size. As any barista in the middle of a rush can tell you, the fluctuating temperature of a busy espresso grinder can wreak havoc on espresso parameters. Shot times will speed up as the temperature increases in the machine during the morning rush, only to slow to a crawl once the line dies down and the machine cools.
義式磨豆機的問題
不論你選錐刀還是平刀磨豆機，實際上所有義式磨豆機都有兩個困難要克服：溫度的起伏及研磨的殘粉。
摩擦生熱，而研磨煮espresso的咖啡豆時，因為咖啡豆要磨得極細而不斷摩擦，任何咖啡師再忙都知道，義式磨豆機研磨時造成溫度的起伏將會嚴重破壞濃縮咖啡的參數，在早上營運尖峰時段，沖煮時間將會隨著磨豆機溫度的上升而加快，只能停止運轉讓機器冷卻。
 


Previously, a popular explanation was that the temperature fluctuation was causing the burrs to expand and contract. This theory has been soundly rejected. Even the hottest grinders don’t reach the necessary temperature to cause steel or titanium to expand. More recently, theorists have proposed it’s the coffee’s changing temperature that produces the difference. Cooler coffee is more brittle, causing more fines to be produced during grinding. Conversely, at higher temperatures coffee beans are more malleable, reducing the production of fines. Fewer fines result in a faster flow rate, thus explaining the change in shot times.
先前一種說法是溫度的起伏造成刀盤的擴張與收縮，而這理論已被推翻，即使在磨豆機最熱的時候也不能達到足以讓鋼及鈦金屬變形的溫度。最近提出一個理論是咖啡溫度的變化而形成差異，溫度越低咖啡豆越容易被磨碎，而讓研磨越精細。相反的，當刀盤造成咖啡豆溫度越高，精細程度則降低。精細程度越低造成流速越快，這解釋了為什麼連續大量研磨會改變沖煮時間。


 
Because an ideal grind for filter coffee includes minimal fines, all three companies use flat burrs in their grinders.
Most higher-end espresso grinders try to compensate for temperature issues by using a fan. As temperatures rise, the fan will turn on to cool the grinding chamber. In the case of the Mahlkönig Peak, the barista has the option to turn the fan on constantly. Nuova Simonelli took an unprecedented move by adding a heater in their Mythos Clima Pro One. “It actively heats the grind chamber to between thirty and forty degrees Celsius,” explains Rhinehart. “It will then heat or cool it throughout the day to keep it in that range. Because it holds the temperature stable you don’t see as much variation throughout the day.”
理想的沖煮咖啡應包含最精細的研磨，而這三家公司都用平刀型磨豆機。
最高級的義式磨豆機會利用風扇來解決溫度的問題，當溫度上升時，風扇會啟動來降低磨床的溫度。在Mahlkönig Peak的案例中，咖啡師讓風扇持續運轉。Nuova Simonelli則在Mythos Clima Pro One這台機器加上加熱器。Rhinehar說：「這可讓磨床溫度保持在30到40度間，透過增溫或降溫以維持溫度範圍，為維持溫度的穩定，我們將不會看到太多的變化。


 
Whether you opt for a fan or a heater, make sure your house espresso grinder has some sort of temperature regulation. Cheaper espresso grinders without it might pass as your decaf grinder, but you don’t want to depend on them for any sort of volume.
不論你選擇用風扇或加熱器，都要確保你的義式磨豆機有調節溫度的功能，便宜的義式磨豆機沒辦法調節溫度，研磨粗的咖啡豆可能會變成萃取率較低的咖啡，因此就更不可能應付量大的需求。
 

An even bigger headache for baristas trying to dial in espresso is the grinder’s retention of grinds. Some of the ground espresso will always stay in the chute and between the burrs. This means whenever you grind coffee, at least some of the coffee that comes out of the grinder was ground previously.
對咖啡師來說磨豆機更讓他們頭痛的問題就是殘粉，一些咖啡粉會留在磨豆機的溝槽及刀盤間，這代表無論何時你研磨咖啡，都會伴隨先前某些咖啡豆的殘粉。
 
 
“I think grinder technology has a long, long way to go in improvements in the core ability to grind coffee,” says Mark Prince, senior editor of coffeegeek.com. “My main concern is stale coffee. Far too many grinders leave up to ten grams of ground coffee inside their chutes, channels, and burr sweep areas between grinding sessions. Freshness of the grind is 100 percent more important, in my opinion, than the slight differences between what a quality flat burr grinder can produce compared to a conical burr grinder.”
Coffeegeek.com的高級編輯Mark Prince說：「我認為改進磨豆機研磨咖啡的核心功能還有很長的路要走，我主要擔心會有不新鮮的豆子，有許多磨豆機會有將近十克的咖啡殘粉，遺留在磨豆機的溝槽、刀盤運轉的區域。咖啡豆最重要的是新鮮，就我來看，平刀跟錐刀磨豆機磨出來的品質差異很些微。
 
 
Beyond freshness issues, grind retention is also a problem when adjusting settings. Even if you purge two to three doses, you can not be completely sure all of the previously retained coffee has been expunged. As a result, future shots might be a mixture of multiple particle sizes, leading to uneven extraction and increasing the chances of channeling.
探討新鮮度問題時，殘粉依舊是調整參數時的問題，即使你磨了兩到三份豆，你仍然不能完全確認先前磨的咖啡都不在機器裡，因此，研磨出來的咖啡則會有不同的粒徑大小，導致不均勻的萃取、及增加阻塞的機會。

Filter Grinders
Although expresso grinders present the greatest challenges, equal thought should be put into choosing and maintaining your filter grinder. Filter grinders grind larger, coarser batches, which requires components built to withstand higher volumes while still providing a precise particle size distribution.
家用單品磨豆機
雖然義式磨豆機有許多艱鉅的挑戰，我們也要同時專注在選擇及維護它，磨豆機磨了更大更粗的咖啡粉，表示它要能承受更大的用量，並同時提供精確的粒徑分布。
 

 
“Volume is a big thing,” says Rhinehart. “If you’re brewing a two-gallon Fetco, and you’re brewing a fresh one every hour or more, you need a grinder that can keep up with that volume.” Reinhart suggests checking the manufacturer’s recommended usage, and then erring on the cautious side. “You don’t want to be stuck with a grinder that’s going to break down faster because you’re putting undue stress on it,” he says.
Rhinehart說：「產量也很重要，如果你要每小時沖煮兩加侖的滴漏咖啡，你會要一台磨豆機以達到需求產量」，Reinhar建議確認製造商所寫的建議使用方式，並小心使用。「你不會希望因為過度使用，讓磨豆機運作被影響、而造成損壞」。
 


For bulk filter grinders, three companies dominate the market: Mahlkönig, Ditting, and Bunn. Because an ideal grind for filter coffee includes minimal fines, all three companies use flat burrs in their grinders. “You can’t go wrong with any of them,” says Rhinehart, who does admit to a preference for Mahlkönig products.
量產磨豆機的廠商龍頭為：Mahlkönig、Ditting、 Bunn，因為家用單品磨豆機需要極精細的研磨，這三家公司都使用平刀型磨豆機。Rhinehart說：「有了它們你不可能出錯。」而他也承認它對Mahlkönig產品的偏好。
 


For cafés that serve both batch brew and by-the-cup offerings, Rhinehart recommends having a designated coffee grinder for pour-overs. “It’s a wise investment path,” he says. “If you have to take your grinder down to replace the burrs you still have another grinder.”
對於同時提供手沖咖啡及濃縮咖啡的咖啡店，Rhinehart建議可以設計倒殘渣的地方：「這是很好的投資，如果你必須卸除磨豆機的刀盤，你還是需要另一台磨豆機運作」。（咖啡苗認為，這段應該在寫敲粉台或拆卸磨豆機清理的方便、區域設計，如有些磨豆機會設計敲粉台抽屜，讓清理與保養更加簡易。）
 


At the end of each day, grinders should be vacuumed out and the hoppers should be wiped clean.
One grinder custom-tailored for manual brew methods is the Baratza Forté. This flat-burr grinder features innovative grind-by-weight technology that allows the barista to program the grinder to grind a precise amount of coffee. “It reduces the amount of labor time,” explains Kennedy. “And it reduces one thing they have to think about.” Kennedy also sees another use for grind-by-weight grinders. “It’s a great coffee grinder to be used in restaurants and offices. It gives the coffee shop control over how their coffee is being brewed,” she says.
當每天結束沖煮時，必須用吸塵器清乾淨磨豆機內部，並清潔豆槽（咖啡苗建議，如要清洗豆槽，請使用海綿不要使用菜瓜布，以免刮傷豆槽。）
Baratza Forté是客製化來手沖咖啡的磨豆機，平刀型搭配創新的研磨重量技術，使得咖啡師可以精準秤量咖啡粉重。Kennedy說：「這減少了人工的製程，也減少一個咖啡師要操心的事，這很適合用在餐廳或辦公室裡，這可以管控咖啡店如何沖煮他們的咖啡。」

Grinder Care and Maintenance
After you select the right grinders for your café, proper care and maintenance is essential for proper function and product longevity.
At the end of each day, grinders should be vacuumed out and the hoppers should be wiped clean. Periodically, espresso grinders should be disassembled and deep cleaned, as fines and oils will accumulate over time. Be sure to read the manual and contact the manufacturer before disassembling.
磨豆機維護及保養
選擇適當的磨豆機後，合宜的維護及保養對磨豆機的功能及耐久性很重要。每天結束使用時，磨豆機必須徹底清潔內部，並將溝槽擦拭乾淨。而義式磨豆機必須定期拆解並深層保養，清潔累積的細粉及油脂。務必觀看使用指南並在拆解磨豆機前聯絡製造商。



Café managers should also keep a record of how many pounds of coffee passes through a grinder each year. Different burrs have different life spans, but most busy cafés should plan on changing the burrs of their main grinders annually.
咖啡店的經理則必須記錄每年磨豆機磨了多少磅重的咖啡，不同的刀盤有不同的生命週期，但生意好的咖啡店必須每年定期更換主磨豆機的刀盤。
 
 

—Michael Butterworth is a barista and trainer at Louisville’s Quills Coffee and founder of theCoffee Compass.
作者Michael Butterworth是Louisville Quills Coffee的咖啡師兼員工訓練者，他也是Coffee Compass的創辦人。

Original Source:
http://www.freshcup.com/grinding-for-a-purpose/