手機APP下載

您現在的位置: 香港集運王 > 在線廣播 > 科學美國人 > 科學美國人科學系列 > 正文

科學美國人60秒:研磨粗糙一些 咖啡口感可能更佳

來源:可可英語 編輯:aimee   VIP免費外教試聽課 |  可可官方微信:ikekenet
 下載MP3到電腦  批量下載MP3和LRC到手機
加載中..
LbMZx;h@,oyXUR=eNhKE

+ra0TtX@8L^j2YZI)n

This is Scientific American's 60-second Science. I'm Karen Hopkin.
Making a cup of coffee isn't rocket science. But a new study shows that a background in math and analytical chemistry doesn't hurt. Because researchers who applied their skills in materials science and modeling to brewing espresso have made a grounds-breaking discovery: contrary to popular belief, using fewer beans and a coarser grind will give you a more consistent shot. Their work appears in the journal Matter.
If you're a coffee aficionado, you've no doubt noticed that some days, you may get a great espresso; other days, not so much. Even with the same coffee, the same machine, the same settings.
To understand that variability, the researchers developed a mathematical model to explore how coffee is extracted or dissolved as water passes through the bed of grounds.
"Basically, what we did was to start by writing down some equations, which apply to just a single ground."
Jamie Foster, a senior lecturer in mathematics and physics at the University of Portsmouth.
"So it's a less intimidating task, because in a real coffee bed, you've got millions and millions of particles that are packed together in this very complicated way. And so a more tractable problem is to write down the equations on a single ground."

i_j)ki54oVn0PPkZoOC

咖啡.jpg
To model the entire coffee bed, Foster and his colleagues copied that equation millions of times, stirred in a bit more math and then poured on the theoretical water.
"The model tells us what we should expect in an ideal situation when all of the coffee is being contacted by all of the water equally."
Christopher Hendon, a computational chemist at the University of Oregon, who also took part in the study.
"And indeed, the model describes reality very well for particular grind settings, where there is a sufficient amount of large particles so the water can flow freely through that bed. But when you grind sufficiently fine, that's when we started to see, in real life, a divergence from the expectation that the model was telling us."
With the fine grind, some shots were stronger than predicted. But some were considerably weaker, which flies in the face of conventional wisdom.
"The thinking, if you want a stronger cup of coffee, is, well, I'll grind it finer, because by doing that, I'll have smaller particles in my grounds, and the smaller particles will have a higher surface area. And so this high surface area allows for more rapid extraction from the grains."
But what the researchers found is...
"If you kind of overdo the grinding, what ends up happening is: the particles are so small, in fact, that they kind of clog up the gaps where the water's trying to flow. And that actually hampers the extraction rather than helping it."
And the same is true for the amount of coffee you start with—so that less can, counterintuitively, end up tasting like more.
"Since these articles came out, there has been a tremendous amount of activity on Twitter—arguing, discussing, just general excitement and interest in the project. And independent of whether this helps make more reproducible coffee or not, this is a tremendous success—that we have got millions of people to have read a scientific article and engage with science. That's a great success for scientific literacy."
And we can all drink to that.
Thanks for listening for Scientific American's 60-second Science. I'm Karen Hopkin.

V4_-6QUNG,

Y[YOa|TelvBv18P

HbIstOtRr,e#7RjwjiD=mw[r3L=JJznAeN6EcP-A69sQj=vQ_

重點單詞   查看全部解釋    
foster ['fɔstə]

想一想再看

vt. 養育,培養,促進,鼓勵,抱有(希望等)

聯想記憶
extraction [iks'trækʃən]

想一想再看

n. 抽出,取出,抽出物 n. 血統

聯想記憶
understand [.ʌndə'stænd]

想一想再看

vt. 理解,懂,聽説,獲悉,將 ... 理解為,認為<

 
moderate ['mɔdəreit,'mɔdərit]

想一想再看

adj. 適度的,穩健的,温和的,中等的
v.

聯想記憶
equation [i'kweiʃən]

想一想再看

n. 相等,方程(式), 等式,均衡

聯想記憶
engage [in'geidʒ]

想一想再看

v. 答應,預定,使忙碌,僱傭,訂婚

 
complicated ['kɔmplikeitid]

想一想再看

adj. 複雜的,難懂的
動詞complica

 
theoretical [θiə'retikəl]

想一想再看

adj. 理論上的

 
expectation [.ekspek'teiʃən]

想一想再看

n. 期待,期望

聯想記憶
grind [graind]

想一想再看

vt. 磨,碾碎,擠壓,壓迫
vi. 磨得吱吱

 
發佈評論我來説2句

    最新文章

    可可英語官方微信(微信號:ikekenet)

    每天向大家推送短小精悍的英語學習資料.

    添加方式1.掃描上方可可官方微信二維碼。
    添加方式2.搜索微信號ikekenet添加即可。