如何调制完美的咖啡_English Corner

How to Make Perfect Coffee

Coffee has become recognized as a human necessity. It is no longer a luxury or an indulgence; it is a corollary of human energy and human efficiency.

- William H. Ukers, All About Coffee (1922)

It was November 23, 2010. We were in Surf City, North Carolina, getting ready to fortify ourselves before another grueling day. As the thin, black liquid oozed into the stained carafe, we stood bleary-eyed.

We were roommates, Marine infantry officers, perpetually sleep-deprived from the training, the planning, the preparations for war. Back then coffee was little more than a bitter, caffeine-delivery system. It was just what we needed to stay awake.

We were missing so much.

Fast-forward a few years. We've hung up our uniforms, we're in the kitchen, and we're making coffee. Great coffee. The kind that reminds you first thing in the morning of everything else you appreciate in life. It's about the art, the ritual, and the moments shared across a table.

And yet, if you're like us, no one ever taught you how to make coffee properly. Or how to appreciate it. When you stop in at your local coffee shop, everything is hidden away behind the counter, too far removed for you to understand. That was us not too long ago. But through trial and error—and an absurd amount of mistakes—we've managed to learn. It's a shame to waste these moments on bad coffee, and if you're going to drink it every day, or if you're going to serve it to other people, it may as well be good, right?

Actually, it should be better than good. It should be perfect.

What is Good Coffee?

To understand good coffee, we have to start with how the coffee world measures its brews. After all, if you're trying categorize your coffee, it helps if you have a benchmark.

Measuring the quality of coffee goes back to the 1950s, when MIT chemistry professor E. E. Lockhart conducted a series of surveys to determine American preferences. Basically, he surveyed a lot of coffee drinkers and asked them what they liked.

Lockhart published his findings in the form of the Coffee Brewing Control Chart, a graphical representation of what Americans at the time considered to be the best coffee. In the years since, the Specialty Coffee Association of America (SCAA) has confirmed that American tastes haven't changed all that much. Perfection, at least to Americans, is a coffee that falls in the range of 18 to 22 percent Extraction with a brew strength between 1.15 and 1.35 percent Total Dissolved Solids.

Confused by the jargon? Don't be.

The Percentage Extraction is the amount of coffee particles extracted from the original dry grounds. The Percentage of Total Dissolved Solids is the percentage of coffee solids actually in your cup of coffee (commonly known as "brew strength"). When you correlate these, the result is a Coffee Brewing Control Chart, with a target area in the center that highlights the optimal brew strength and extraction percentage.

When you're brewing coffee, the goal is to get into that center square of perfection. Everyone seems to advocate their own sort of mystical process for achieving the right extraction, but we're here to tell you it's not that crazy.

Instead, the key is to start with the Golden Ratio of 17.42 units of water to 1 unit of coffee. The ratio will get you into that optimal zone, plus it is unit-less, which means you can use grams, ounces, pounds, stones, even tons if that's your thing. So if you're hoping for a 20 percent extraction against 1.28 percent Total Dissolved Solids, you can start with 30 grams of dry coffee grounds, 523 grams of water, and then adjust from there.

Meanwhile, a common mistake is to mix up Percentage Extraction with Total Dissolved Solids. It's important to understand the difference.

Strength refers to the solids that have dissolved in your coffee. Percentage Extraction refers to the amount that you removed from the dry grounds. The point is that strong coffee has almost nothing to do with bitterness, caffeine content, or the roast profile, and everything to do with the ratio of coffee to water in your cup.

The great innovation in measuring all this stuff came about in 2008, when a company called Voice Systems Technology decided to use a refractometer—a device that bounces light waves off of particles—in conjunction with a program they developed called ExtractMojo.

The device allows you to get an accurate reading on Total Dissolved Solids and then compare your brews to the Coffee Brewing Control Chart. In this way, you can refine your results based on science as well as taste.

Some purists chafe against the idea of introducing a device like this to measure the quality of a cup of coffee. As former Marines, it reminds us of a similar debate on the topic of gun control.

Are guns the problem, or is it how people use them?

Are refractometers the problem, or is it how people use them?

These are hotly debated issues and for good reason. But both are tools, and just like any other, they can be misused.

We prefer to think of it like castle doctrine; use your refractometer in the privacy of your own home.

The Principles of How to Make Coffee

Once you understand what good coffee actually is, and once you understand how people measure it, it's much easier to learn how to make coffee.

The six fundamental principles are:

Buy good coffee beans: They should be whole beans, sustainably farmed, and roasted within the past few weeks. Plus, if you want to take part in the "third wave" coffee renaissance currently sweeping America, they should be a lighter roast so you can actually taste the flavors—the terroir—of the coffee. With darker roasts, you're missing out. We know it's a weird analogy, but a dark roast is just like taking a nice steak and charring it beyond recognition.

Grind your coffee just before brewing: Roasted coffee is very delicate and perishable. Coffee has many more flavor compounds than wine, but those compounds deteriorate quickly when exposed to oxygen. Grinding your coffee just before you brew it keeps those compounds intact, and it's the number one thing you can do to improve your coffee at home.

Store your coffee properly: Beans which you aren't using immediately should be kept in an airtight container and away from sunlight. A major point of debate in the coffee world is whether to freeze or not freeze your coffee. We fall somewhere in between. If it's going to be more than two weeks before brewing, we freeze our coffee. Otherwise, we avoid it.

Use the right proportion of coffee to water: A major error people make is not using enough coffee. We empathize—it almost seems wasteful to add that extra scoop. But the Golden Ratio we mentioned earlier really is a great starting point and the simplest way to get into that perfect zone.

Focus on technique: It's beyond the scope of this guide to go through step-by-step instructions for every method, but underlying all of them is the fact that brewing great coffee is about precision and consistency. Each brewing method has its own particular techniques, but by doing the same thing over and over you fix your mistakes and improve incrementally.

Use quality tools: You're going to get better results from high quality tools than you will with junk from the bargain bin. Yes, it's more of an upfront investment, but in the long run it's worth it. Good tools last longer and make the entire brewing process much easier.
Classic Methods and Fine Tuning

With these principles in mind, pick a preparation method. These lie along a spectrum: Body on one end, flavor clarity on the other, with variations in between. The balance between body and flavor clarity is determined by the parts of the coffee bean that make it into your cup.

Unfortunately, way back at the beginning of our journey when this was all foreign to us, no one ever explained why a French press had so much body or why a pour over had such articulate flavors. It was all shrouded in secrecy. So we took these mysteries at face value and filed our questions away.

Eventually, we discovered that the answer lay in chemistry, which divides the world into soluble and insoluble compounds. Soluble particles are extracted from the coffee grounds and contribute to flavor and aroma, while insoluble particles primarily contribute to the body of coffee. Since a roasted coffee bean is made up of both types of particles, the way you balance those during the extraction process determines the resulting character of your cup.

Do you prefer a richer, grittier cup of coffee? Try a French press. Looking for a cleaner cup that can highlight citrus notes from South America or berry flavors from Africa? Check out the pour over. Everyone's preferences vary, but once you select a method, you can further fine tune your coffee by adjusting these variables:

The grind size of your coffee beans: Grind size affects the extraction rate because it affects surface area. Beans that are coarsely ground have less surface area than the same amount of finely ground beans, making it more difficult for the water to penetrate and extract the coffee solids. A uniform grind size means that the extraction rate of the oils and acids in the coffee will be consistent. You won't have large pieces that under-extract and small pieces that over-extract. It's for this reason that you'll often hear coffee experts exhorting people to invest in a good burr grinder. And guess what? They're right.

The temperature of your water: Temperature affects extraction rate because solids dissolve more quickly at higher temperatures. Temperature also affects flavor because it determines which solids get dissolved. Using water that's too hot will lead to sour coffee since it releases unpleasant acids from the coffee beans. For this reason, we recommend brewing with water between 195 and 202 degrees. And remember, measure the water actually in the coffee and not just what you're pouring. There's often a difference.

The amount you agitate your coffee grounds during brewing: You can further manipulate the brewing process by agitating the coffee grounds as the water passes through them. Agitation works because it accelerates the spread of dissolved coffee solids throughout the water, exposing the coffee grounds to fresher water more quickly. But agitation also has the effect of cooling the water, which we know can affect the process. In the end, it's just one of those things that you learn through trial and error.

The ratio of water to coffee: Strange how it keeps coming back to this, right? The key difference here is that when you're fine tuning, you aren't sticking strictly to the Golden Ratio. Instead, you're adjusting to taste. To make adjustments more easily, invest in a scale. You can be more precise by using weight—instead of volume—to measure your coffee and water.
One final point. As any good barista will tell you, make sure to adjust only one variable at a time so you can accurately track results. Changing two variables at a time confounds the outcome, and you won't know whether it was because you changed variable X or variable Y.

This Isn't Rocket Science

For all our talk of chemistry, particles, molecules, and extraction percentages, brewing great coffee is much less about science and much more about art. Once you learn the principles that underly the brewing process, you can develop a routine which suits you perfectly.

And that's the beauty of coffee. When we first started our journey, we were embarrassingly ignorant about the most basic aspects. The choices, the culture, the equipment—it was all so overwhelming that we had no clue where to begin.

But pretty quickly we found ourselves climbing the coffee learning curve. Learning to brew great coffee didn't have to take forever. It was a hobby that you could pick up on a Saturday morning and feel good about.

As we explored, there were good moments and bad ones, and stretches where it felt as if we couldn't do anything right. We wasted a ton of time. We destroyed a lot of coffee. And although we read as much as we could, there were occasions when we were as stubborn as we were ignorant, days when we had to learn from our own mistakes because we didn't understand or didn't listen to what we had been taught.

But each mistake also meant progress. We had discovered one more thing which didn't work. There was always something new to try, and in this haphazard fashion, we grew.

For us, this was the enduring lesson, that learning is continuous, that there is always room to improve, to explore, and to innovate.

And while much of the knowledge already existed, and although the modern exploration of coffee has been going on for at least a hundred years, through this journey, it was our turn to participate.

And now it's yours.

咖啡已经成为公认的人类生活必需品。它不再是一种奢侈品，也不再代表放纵；它是人类心血与能力的结晶。
——威廉•H•尤克斯《关于咖啡的一切》（1922）
2010年11月23日，我们在北卡罗来纳州的瑟夫市，正准备为紧张劳碌的新一天充实体力。我们睡眼惺忪地立在那，让稀薄的黑色液体缓缓流进卡拉夫铁瓶中。
我们是室友，同为海军陆战队步兵军官。训练、作战计划以及各种战争准备让我们永远处于缺觉的状态。当时的咖啡不过是一种苦涩的、能提供咖啡因的东西，我们只是需要用它来保持清醒。
我们忽略了咖啡的太多妙处。
几年时光匆匆而过，我们也已解甲归田。如今的我们在厨房里，调制着咖啡。美妙的咖啡。
那种能在每天早上第一时间唤醒你对美好生活感激之情的咖啡。它是艺术，是仪式，是围桌分享的时光。
如果你像我们一样，从来没有人教过你如何正确地调制咖啡，或如何品鉴它。当你驻足当地的咖啡馆，关于咖啡的一切都隐藏在柜台后面，离你太远而无法让你去了解。不久之前，我们就是那样。但我们经历反复的试验，犯的错误多得离谱，而后终于学会了正确的方法。在糟糕的咖啡上浪费这些时间多么让人惭愧。如果你每天都要喝，或是每天都要调制给别人喝，还不如把咖啡品质做得好一点。我们想要的是好咖啡，对吧？
实际上，我们要的不止是好咖啡，而是完美的咖啡。
什么是好咖啡？
想要了解什么是好咖啡，我们首先要知道咖啡界对其冲煮技术的衡量标准。毕竟，如果你想判定自己咖啡能否归为佳品，有一个标准做参考会很有帮助。
衡量咖啡品质这件事可以回溯到二十世纪五十年代。当时麻省理工大学化学系教授E.E.洛克哈特进行了一系列调查，来研究美国人的口味偏好。他大体上就是对许多喝咖啡的人进行了调查，询问他们的喜好的口味。
洛克哈特用一张“咖啡冲煮控制图”发表了他的研究成果，用图表的形式呈现出当时的美国人心目中最好的咖啡是怎样的。多年以后，美国专业咖啡协会（SCAA）证实了美国人的口味变化不大。至少对美国人来说，完美的咖啡就是提取率在18%~22%、冲煮后固体总溶解量在1.15%~1.35%范围内的咖啡。

为专业术语而困惑？别这样。
提取率是指从原始的干咖啡渣种中提取出的咖啡粒子的量。固体总溶解量表示咖啡固体在一杯咖啡中的实际占比（也就是通常说的“冲煮强度”）。把这些信息联系起来，你就得到了咖啡冲煮控制图，图中中心区域突出显示的就是冲煮强度与提取率的最优组合。
我们调制咖啡的目的是要至臻完美。似乎每个人都在吹嘘自己的达成最佳提取率的独特而神秘的过程，但我们在这里告诉你，这没什么了不起。

相反，这其中的关键是要以1份咖啡兑17.42份水的黄金比例为基础。这个比例最能让你达到最佳区域，并且没有单位限制，也就是说你想以克、盎司、磅、英石还是以吨位单位都是你自己的事儿。因此，如果你想调制提取率为20%且固体总溶解量为1.28%的咖啡，你可以用30克干咖啡原料加523克水打底，然后以此为基础进行调整。
同时，人们常常错将提取率和固体总溶解这两个概念混淆。搞清楚这两个概念的区别很重要。
冲煮强度是指溶解在你咖啡里固体咖啡的量。而提取率表示你从干咖啡原料里得到的提取物的量。重点是，浓咖啡和苦涩度、咖啡因含量或者烘焙曲线没有任何关系，只和你杯子里咖啡和水的比例有关系。
所有这些数值的测量方法在2008年得到了伟大的革新。一家名为“语音系统技术公司”的企业决定将折射计原理——折射计是一种用来侦测粒子折射的光波的仪器——应用到一个项目中，并由此开发出一款叫做ExtractMojo的咖啡浓度分析仪。
这个仪器可以精确显示咖啡的固体总溶解量值，再将其与“咖啡冲煮控制图”对照，就可以既科学又注重口味地调制出更好喝的咖啡了。

有些纯粹主义者反对用这样的设备来衡量一杯咖啡的品质，这让作为退役海军陆战队员的我们想到一个类似的话题，那就是大家对于熗支管控的讨论。
是熗支本身有问题，还是大家使用熗支的方式有问题？
是浓度分析仪有问题，还是大家使用这个仪器的方法有问题？
这些问题引发了激烈的讨论，讨论的出发点是好的。但是熗支和浓度分析仪都是工具，与其他工具一样，他们也都可能被不恰当的使用。
让我们还是用“堡垒原则”(castle doctrine)来看这个问题吧：在家悄悄的用浓度分析仪就好了。
冲煮咖啡的基本原则

一旦弄明白什么是好咖啡以及大家是如何衡量好坏的，学会冲煮咖啡就容易多了。
六个基本原则是：
1.选购优质咖啡豆：请选用可持续种植的全豆咖啡，采摘后几周内即要进行烘焙。而且，如果你有意加入如今正风行全美的咖啡复兴运动“第三次浪潮”(third wave)，就选择用较轻度烘焙的咖啡豆，这样才能真正品尝到咖啡特有的风味。深度烘焙会使咖啡豆失去这些风味。我们知道这样说听起来有点奇怪，但是深度烘焙的咖啡豆就好比一块本来还不错但被烤得面目全非的牛排。
2.冲煮咖啡前现磨咖啡：烘焙过的咖啡豆是很脆弱且易腐坏的。咖啡比红酒含有更多香味成分，但是这些香味成分被氧化后很快会变质。冲煮咖啡前现磨咖啡可以保留这些成分的原味。想让你的自调咖啡更好喝，这是最重要的一点。
3.正确存放咖啡：不立即用的咖啡豆应存放在密闭容器中，避免阳光照射。对于咖啡是否要冷藏储存这个问题，咖啡界内存在诸多争议。我们可以折中一下。两周内不会用的咖啡豆可以冷藏存放；两周内会用到的咖啡豆就不用冷藏。
4.正确配比咖啡和水：大家常犯的一个错误就是咖啡放的不够多。我们舍不得——总觉得多放一勺咖啡就跟浪费了似的。但是之前我们提到过的黄金比例绝对是做出好咖啡的重要起点，也是达到这个目的的最简单方法。
5.注重技巧：讨论如何一步步完成每种冲煮咖啡的方法超出了这篇文章的范畴，但是所有方法背后有一个共通事实，那就是做出好咖啡是一件要求准确度和协调性的事。每种冲煮方法都有些特殊技巧，但经过一遍又一遍的反复练习，你就能修正错误，进步越来越大。
6.使用优质工具：相较于从打折区里淘来的便宜货，优质工具冲煮出的咖啡会更好喝。是的，这些工具更像是前期投资，但长远来看是值得的。优质工具的使用寿命更长，也能让冲煮咖啡的整个过程简单很多。
经典微调方法：

记住这些原则之后，就可以选择一种咖啡冲煮方法了，而所有冲煮方法要考虑到的因素不外乎这些：一个是咖啡的醇厚度，一个是咖啡风味的纯正度，还有就是两者的组合变化。醇厚度和纯正度两者之间的平衡在一定程度上取决于用来做这杯咖啡的咖啡豆。
在我们刚刚开始接触这一切、对咖啡还不熟悉的时候，可惜没人能解释清楚为什么法式压滤壶(French press)做出的咖啡如此醇厚，或是为什么手冲咖啡(pour over)能有这么纯粹的口味。这些问题的答案被竭力掩藏起来。我们只看到这些不解之谜的表象，把疑问暂搁一旁。
最终我们通过化学方法找到了问题的答案。从化学角度来说，世界中的物质被分为可溶解物质和不可溶解物质两类。从咖啡粉中萃取出的可溶解颗粒产生了咖啡特有的风味和气味，而不可溶解颗粒的主要作用则是使咖啡有了醇厚感。烘焙过的咖啡豆由这两种颗粒共同构成，所以萃取过程中如何平衡这两种成分，也就决定了你的咖啡最后会是怎样。
你更喜欢口感较浓郁、砂感较强的咖啡？试试法式压滤壶吧。在寻觅口感纯净、能突出南美咖啡豆的柑橘香或是非洲咖啡豆浆果风味的咖啡？去瞧瞧手冲咖啡机。大家各有所好，但只要选好了冲煮方法，你便可以通过调节这些变量来进一步对咖啡进行精细的调配：
1.咖啡豆的研磨粒度：研磨粒度影响着颗粒的表面积，进而影响提取率。粗磨的咖啡豆与等量细磨的咖啡豆相比，表面积更小，使得水分更难进行渗透或提取咖啡固体。均匀的研磨粒度意味咖啡中油与酸的提取率相当，从而不会出现未被充分萃取的大颗粒或是萃取过度的小颗粒。这也正是咖啡专家们总是倡导大家购置一台优质磨盘式研磨机的原因。你猜怎么着？他们是对的。
2.水温：由于温度较高时，固体溶解得更快，所以温度影响提取率。此外，温度还决定着哪种固体会溶解，进而影响口味。水温过高会使得咖啡发酸，因为高温会把咖啡豆中口感不佳的酸性物质释放出来。因此，我们推荐你使用195至202华氏度的水来冲煮咖啡。请记住，这里是指咖啡的实际温度，而不是水温。二者之间通常是有差异的。
3. 冲煮时搅动咖啡渣的次数：你可以在水流经过时，搅动咖啡渣，进一步控制冲煮过程。搅动之所以有用，是因为它会提高已溶解的咖啡固体在水中的扩散速度，让咖啡渣能够更迅速地接触到水。但搅动同样有降低水温的作用，我们知道这会影响冲煮过程。但说到底，这只是那种你反复摸索就能掌握的技巧。
4．咖啡和水的配比：说来说去都要回到这一点上，有点奇怪，对吗？但这里的关键区别在于，调配咖啡时，你不用严格依照黄金比例。而是，依照个人口味进行调节。为了使调配更容易，购置一台天平吧。与测容量比起来，测咖啡和水的重量得出的结果会更加精确。
最后一点。好的咖啡师会告诉你，保证一次只调节一个变量，这样才能够准确地观测到成果。一次调节两个变量，会混淆结果，你会分不清究竟是变动了X变量还是Y变量，引发了结果的变化。
这可不是什么复杂的航天科学
尽管我们大谈特谈了化学反应、粒子、分子以及提取率等概念，煮出好咖啡与其说是门科学，不如说是门艺术。一旦掌握了冲煮程序背后的规律，你就能研究出一套最适合自己的方法。
那就是咖啡的魅力所在。刚进入这个领域的时候，我们十分尴尬，对大部分的基本知识都一无所知。选料、加工、器具——一股脑全涌过来，我们根本无从下手。
但很快，我们就会发现，自己正沿着咖啡研习之路向上攀爬。煮出好咖啡并不必穷其一生。它是我们可在周六早上随手练起、陶冶情操的一种爱好。
随着我们不断地摸索，情况也时好时坏，我们有时会陷入窘境、手足无措。我们耗费了大量时间。我们浪费了许多咖啡。尽管我们尽可能多地阅览相关书籍，有时还会固执己见、无知盲目，总会有那么几天，由于不理解、不依照别人教授的技巧来操作，我们犯了错误，然后才将要领掌握。
但是，吃一堑、长一智。我们便总结出了哪些方法是不凑效的。总有新鲜的事物去尝试，我们也便这样无计划地自然成长着。
对我们来说，这是一项长期的修行，我们一直在学习，总有提高、探索及创新的空间。
大多数咖啡相关的知识早就存在，而且现代人对咖啡的探索也已持续了一百多年。那么现在，则轮到我们投身这趟咖啡学习之旅了。
现在轮到你行动了。

[Free Talk] 如何调制完美的咖啡