科学家们说，让我们回到浓缩咖啡的制作上

科学家们说，让我们回到浓缩咖啡的制作上

The morning coffee is a sacred drink. Get it right and you’re set for the day, but if it’s wrong the hours stretch ahead of you. If your drink of choice is an espresso, you’re probably used to variation between your brews.

早晨的咖啡是神圣的饮料。如果做对了，你就为这一天做好了准备，但如果做错了，你的时间就会延长。如果你选择的饮料是浓缩咖啡，你可能已经习惯了不同的口味。

Katy Pallister

However, a study published in the journal Matter by a multi-disciplinary team from four countries has used mathematical modeling to help produce a more consistent espresso. The answer? Fewer coffee beans, ground more coarsely, and less water use.

然而，来自四个国家的一个多学科团队在《Matter》杂志上发表的一项研究已经使用数学模型来帮助生产更一致的意式浓缩咖啡。答案是什么?咖啡豆越少，研磨越粗糙，用水量越少。

As Dr Jamie Foster, a mathematician from the University of Portsmouth and co-author of the research, explained: “The conventional wisdom is that if you want a stronger cup of coffee, you should grind your coffee finer. This makes sense because the finer the grounds mean that more surface area of coffee bean is exposed to water, which should mean a stronger coffee.”

正如朴茨茅斯大学数学家、该研究的合著者杰米•福斯特博士所解释的那样:“传统观点认为，如果你想要更浓的咖啡，就应该把咖啡磨得更细。”这是有道理的，因为咖啡渣越细，咖啡豆接触到水的面积就越大，这就意味着咖啡越浓。”

Dr Jamie Foster, co-author of the paper, wanted to challenge the "common espresso wisdom". University of Portsmouth

Not only are coffee beans ground finely, but current brewing techniques rely on a relatively large mass of coffee beans, around 20 grams (0.7 ounces), to make an espresso shot.

不仅咖啡豆磨得很细，现在的冲泡技术也需要大量的咖啡豆，大约20克(0.7盎司)，才能做出一杯浓咖啡。

In practice, the team found that this method resulted in clogging of the coffee bed – what you find in the basket of an espresso machine – inhibiting the water’s passage. This spells bad news for a multitude of reasons. The amount of coffee dissolved in the water (extraction yield) is reduced, leading to a waste of raw material and a variation in taste.

在实践中，研究小组发现，这种方法会导致咖啡床堵塞——就像你在咖啡机的篮子里发现的那样——抑制水的流动。从多方面来看，这都是坏消息。咖啡在水中的溶解量(萃取率)降低，导致原料的浪费和口味的变化。

To find a solution, the team started by creating a mathematical model for a single grain of coffee. The extraction yield for the whole brew relies on modeling the extraction of millions of individual grains, which are placed irregularly on the coffee bed. Add to that the variability in the water pressure as it flows through the coffee, and the team had a real problem on their hands.

为了找到解决方案，团队首先为一粒咖啡创建数学模型。整个咖啡的萃取率依赖于对数百万粒单独谷物的建模，这些谷物被不规则地放置在咖啡床上。再加上流经咖啡的水压的可变性，团队面临着一个真正的问题。

In fact, Foster remarked that “you would need more computing power than Google has to accurately solve the physics and transport equations of brewing on a geometry as intricate as a coffee bed.” To simplify the equations, the researchers borrowed modeling methodologies from electrochemistry. Likening how caffeine dissolves out of coffee beans to how lithium ions are transported between the electrodes of a battery proved successful for the team.

事实上，福斯特评论道:“你需要比谷歌更强大的计算能力来精确地解决在像咖啡床一样复杂的几何图形上酿酒的物理和运输方程。”为了简化方程式，研究人员借用了电化学中的建模方法。将咖啡因如何从咖啡豆中溶解出来比作锂离子如何在电池的电极之间运输，这个研究小组被证明是成功的。

Coupling the maths with many shots of espresso, the researchers reached their conclusion. “One way to optimize extraction and achieve reproducibility is to grind coarser and use a little less water, while another is to simply reduce the mass of coffee," said Dr Chris Hendon (aka Dr Coffee), a computational chemist at the University of Oregon and co-author of the paper.

把数学和许多杯浓缩咖啡结合起来，研究人员得出了他们的结论。俄勒冈大学的计算化学家克里斯·亨登博士(又名咖啡博士)是这篇论文的合著者，他说:“优化提取并实现重现性的一种方法是磨出更粗的咖啡，用更少的水，而另一种方法是简单地减少咖啡的质量。”

The team's espresso method for success. Cameron et al. 2020/Matter

When the findings were put into practice at a small US coffee shop, the new recipe was found to save them thousands of dollars every year. If applied to the whole of the US coffee industry, the total savings could stand at $1.1 billion each year.

当研究结果在美国一家小咖啡店付诸实践时，人们发现这种新配方每年能为他们节省数千美元。如果应用于整个美国咖啡行业，每年可节省11亿美元。

“A good espresso beverage can be made in a multitude of ways,” Hendon concluded. “The point of this paper was to give people a map for making an espresso beverage that they like and then be able to make it 100 times in a row.”

“一杯好的浓缩咖啡有很多种制作方法，”亨登总结道。“这篇论文的目的是给人们提供一张制作他们喜欢的浓缩咖啡饮料的地图，然后让他们能够连续制作100份。”