Hey Mental Floss I have a strange question. How do they make decaf coffee when the caffeine is in the bean

Mental Floss你好，我有個奇怪的問題。如果咖啡因是在咖啡豆裡面，他們是怎麼做出無咖啡因的咖啡？

That's not a strange question what's a strange question is why would anyone drinks decaf,

這不是個奇怪的問題，奇怪的是為何會有人想喝無咖啡因的咖啡

but I'll answer your question.

但我還是會回答你的問題。

I want to begin by telling you about a 2006 study done at the University of Florida

我想先告訴你一個2006年在佛羅里達大學所做的研究來做為開場。

researchers tested ten 16 ounce decaf coffees from 9 coffee shops

專家們測試了十杯九家不同咖啡店的 16 盎司無咖啡因咖啡。

they found that nine of the 10 cups contain between 8.6 milligrams and 13.9 milligrams of caffeine

他們發現十杯裡面有九杯的咖啡因含量介於 8.6 mg 和 13.9 mg 之間。

and 0 milligrams of purpose.

沒有一杯是完全無咖啡因的。

Put that aside this is still much less than a regular eight-ounce cup of coffee which has about eighty five milligrams of caffeine.

把這方一邊不談，這還是比一杯八盎司咖啡的咖啡因含量還少，它有 85 mg的咖啡因。

The only cup that didn't contain any caffeine was Instant Decaf folders Coffee Crystals

唯一杯沒有任何咖啡因的是 "Instant Decaf folders Coffee Crystals" 的咖啡。

Why am I telling you this?

為什麼我要告訴你這些呢?

Well, I thought you should know that decaf coffee isn't always perfectly decaffeinated

這麼嘛...我想你應該要知道去咖啡因咖啡並不是完全無咖啡因的。

If you're trying to go caffein free, be aware what you're drinking plus it allows me to tell you without shocking you

如果你想要無咖啡因，你應該注意一下你所喝的咖啡，還有這也讓我在不嚇到你的同時告訴你，

that decaffeination process doesn't remove a hundred percent of caffeine from coffee beans usually 94 to 98 percent is removed.

去咖啡因的過程並不會百分之百的把咖啡因從咖啡豆中完全去除，通常只除去 94% 到 98%。

See, you are not shock now because I told you that.

看吧~ 你沒有嚇到對不對，因為我已經跟你講了。

So it's back up to before those the decaf coffees were lying to unsuspecting consumers when they were just little caffeinated beans

讓我們倒退一下，回到這些含少許咖啡因的咖啡豆變成自稱無咖啡因的咖啡豆來欺騙無知民眾之前。

Before coffee beans are right and are roasted they are green

在咖啡豆被剝皮和烘焙之前，它們是綠色的。

It's these green coffee beans that are used in a decaffeination process

而這些綠色的咖啡豆才是用來去咖啡因用的豆子。

before any other step the beans are usually soak in water or steam

在進入其他步驟前，這些豆子通常會泡在水哩，或用蒸氣蒸，

because it makes it easier for caffeine to be extracted

因為如此才能讓咖啡因更容易被萃取出來。

and the ideal temperature for decaffeination is a 162 to 210 degrees Fahrenheit

而去咖啡因最佳的溫度是介於華氏 162 到 110 度之間。

or blah de blah Celsius. I'm....not a Canadian I don't know.

或是攝氏...嗯...不知道多少度。我是....加拿大人，所以我不太清楚。

There are a few different methods for decaffeinated coffee beans one of these is called supercritical carbon dioxide decaffeination

有幾個不同的方法可以去咖啡因，其中一個是「超臨界液態二氧化碳法」。

just felt like it needed to be said like that green coffee beans are put in a

我只是覺得這樣念會聽起來比較專業。

Green coffee beans are put in a pressure vessel with air pressure at around two hundred and fifty times what we're used to.

綠咖啡豆會被放進一個加壓管裡，裡面的氣壓是250大氣壓。

carbon dioxide in the vessel is used as a solvent to remove the caffeine

在管子裡的二氧化變成了幫助去除咖啡因的溶劑。

A few hours later the carbon dioxide now containing the caffeine is removed from the vessel,

幾個小時候，含咖啡因的二氧氧化碳會從管子裡移除。

another way to decaffeinated coffee beans is the direct solvent method

另一個去咖啡因的方式是「直接溶解法」。

Instead of using carbon dioxide to remove caffeine a different solvent is used like that chloro methane or ethyl acetate

有兩種不同的溶劑可以用代替二氧化碳來去咖啡因，一個是氯甲烷，另一個是乙酸乙酯。

basically back in store the caffeine is in the bean

基本上咖啡因就在咖啡豆裡。

but we can use different solvents to remove the majority of that caffeine

但是我們可以用不同的溶劑把大部分的咖啡因去除掉。

and here's a little historical background so you can impress your friends.

這還有個小歷史故事，你可以用來在你朋友面前賣弄一下知識。

Decaf coffee was invented by a German man and Ludwig Roselli in the early nineteen hundred's

無咖啡因咖啡是由一位德國人和 Ludwig Roselli 在19世紀發明的。

He used the chemical compound benzene, not to be confused with my last name

他使用了化學物苯，不要把這個跟我的姓搞錯囉!

I'm green coffee beans. in those days benzene was also used in after shave and pain it turns out benzene is not good for you

哈哈我是綠咖啡豆。在那個時候，苯適用於鬍後水和止痛用的，而苯是對你身體不好的東西。

if you have a big question on your own that you'd like answered leave it below in the comments

如果你有甚麼特別的問題想要問，請在底下留言。

Thanks for watching Mental Floss on YouTube see you next week come on by to see what bruin you probably won't have anything but coffee.

感謝你在YouTube在收看Mental Floss。下禮拜見，順便來看一下有甚麼是「熊熊先生」，除了咖啡應該沒甚麼可以給你了。