Why does your mouth feel like it's on fire when you eat a spicy pepper?
为什么吃辣椒时嘴里像是着了火一样？
And how do you soothe the burn? Why does wasabi make your eyes water?
怎样才能缓解这种灼烧感？为什么山葵酱能让人流泪？
And how spicy is the spiciest spice? Let's back up a bit.
最辣的辛香料究竟有多辣？让我们从头说起。
First, what is spiciness?
首先想一个问题：什么是辣味？
Even though we often say that something tastes spicy, it's not actually a taste, like sweet or salty or sour.
我们常说一些食物很辣，但实际上辣并不是一种味道，它不同于甜、咸、酸这些可以尝到的味道。
Instead, what's really happening is that certain compounds in spicy foods
之所以会感到辣是因为辛辣食物中的一些复合物
activate the type of sensory neurons called polymodal nociceptors.
激活了人体中一种叫“伤害性感受器”的感觉神经元。
You have these all over your body, including your mouth and nose,
这种神经元遍布全身，嘴和鼻中就有这种神经元。
and they're the same receptors that are activated by extreme heat.
值得一提的是，当身体接触到热烫物体时，也能激活这种神经元。
So, when you eat a chili pepper, your mouth feels like it's burning
当你吃辣椒时，嘴里之所以像是着了火，
because your brain actually thinks it's burning.
是因为大脑的确认为嘴里起火了。
The opposite happens when you eat something with menthol in it.
而如果这时再吃一些含薄荷醇的食物，嘴里就会有相反的感觉。
The cool, minty compound is activating your cold receptors.
这是因为凉凉的薄荷味复合物激活了你的冷觉感受器。
When these heat-sensitive receptors are activated,
当热敏感受器被激活，
your body thinks it's in contact with a dangerous heat source and reacts accordingly.
大脑会认为你贴近了危险的热源，身体会做出一定的反应。
This is why you start to sweat, and your heart starts beating faster.
因此这时你会开始流汗，心跳加速。
The peppers have elicited the same fight-or-flight response with which your body reacts to most threats.
吃辣椒引起的身体本能反应跟身体应对危险状况的本能反应是一样的。
But you may have noticed that not all spicy foods are spicy in the same way.
你可能已经发现不同辣食的辣味各有不同。
And the difference lies in the types of compounds involved.
食物中的不同复合物形成了不同的辣味。
The capsaicin and piperine, found in black pepper and chili peppers,
比如，黑胡椒和红辣椒中含有的辣椒素和胡椒碱
are made up of larger, heavier molecules called alkylamides, and those mostly stay in your mouth.
是由一种叫“烷基胺”的分子组成，这种分子较大、较重，能滞留在嘴中。
Mustard, horseradish, and wasabi are made up of smaller molecules, called isothiocyanates,
而芥末酱、辣根酱、山葵酱中含有一种叫“异硫氰酸盐”的分子，这种分子较小，
that easily float up into your sinuses.
能轻松扩散到鼻窦处。
This is why chili peppers burn your mouth, and wasabi burns your nose.
所以，吃红辣椒时嘴里会有灼烧感，而吃山葵酱时鼻子里会有灼烧感。
The standard measure of a food's spiciness is its rating on the Scoville scale,
食物辣度的标准计量方法是借助史高维尔辣度单位，
which measures how much its capsaicin content can be diluted before the heat is no longer detectable to humans.
测量方法是不断稀释被测物中的辣椒素，直到人感觉不到辣为止。

A sweet bell pepper gets 0 Scoville heat units, while Tabasco sauce clocks in between 1,200-2,400 units.
甜椒的史高维尔辣度单位是0，塔巴斯科辣沙司的辣度单位在1200-2400之间。
The race to create the hottest pepper is a constant battle,
现在，培植最辣辣椒俨然成为一种国际竞赛。
but two peppers generally come out on top: The Trinidad Moruga Scorpion and the Carolina Reaper.
目前公认最辣的两种辣椒是：千里达莫鲁加毒蝎椒和卡罗来纳死神辣椒。
These peppers measure between 1.5 and 2 million Scoville heat units, which is about half the units found in pepper spray.
这两种辣椒的史高维尔辣度单位在150-200万之间，相当于一半的辣椒喷雾剂辣度单位。
So, why would anyone want to eat something that causes such high levels of pain?
为什么有人愿意吃能造成如此巨大痛苦的食物呢？
Nobody really knows when or why humans started eating hot peppers.
我们无法得知人类最早食用辣椒的时间和原因。
Archaeologists have found spices like mustard along with human artifacts dating as far back as 23,000 years ago.
考古学家从两万三千多年前的古人类器皿中发现了类似芥末的香料。
But they don't know whether the spices were used for food or medication or just decoration.
但尚不明确这些香料是用作调味、治病，还是仅仅作为装饰。
More recently, a 6,000 year old crockpot, lined with charred fish and meat, also contained mustard.
最近，考古学家还发现一个六千多年前的瓦罐，罐旁有烤鱼和烤肉的遗迹，罐内有芥末。
One theory says that humans starting adding spices to food to kill off bacteria.
有观点认为古人类从这时开始在食物中加入香料，以此杀菌。
And some studies show that spice developed mostly in warmer climates where microbes also happen to be more prevalent.
一些研究显示，在古代，香料主要生长在气候较热的地区，而这些地方也更容易滋生细菌。
But why we continue to subject ourselves to spicy food today is still a bit of a mystery.
至于为什么人类到了今天仍对辛辣食物欲罢不能，这还是个解不开的谜团。
For some people, eating spicy food is like riding rollercoasters;
对一些人来说，吃辛辣的食物就像坐过山车，
they enjoy the ensuing thrill, even if the immediate sensation is unpleasant.
虽然当时最直接的感受并不舒服，但他们非常享受随之而来的刺激感。
Some studies have even shown that those who like to eat hot stuff
还有研究显示，喜欢吃辣食的人
are more likely to enjoy other adrenaline-rich activities, like gambling.
也更乐于从事其他能激起肾上腺素的活动，比如赌博。
The taste for spicy food may even be genetic.
对辛辣食物的喜好程度甚至也有遗传的因素。
And if you're thinking about training a bit, to up your tolerance for spice, know this:
如果你想训练得自己更能吃辣，有这么几条信息跟你分享：
According to some studies, the pain doesn't get any better. You just get tougher.
一些研究显示，辣带来的灼烧感从不会减轻。只是吃辣的人的忍耐力提高了。
In fact, researchers have found that people who like to eat spicy foods
研究人员发现，喜欢吃辣食的人
don't rate the burn any less painful than those who don't.
跟不喜欢吃辣食的人体验到的辛辣感是一样的。
They just seem to like the pain more.
只是喜欢吃辣的人更享受那种灼烧感。
So, torment your heat receptors all you want,
所以，尽情磨练你的热觉感受器吧，
but remember, when it comes to spicy food, you're going to get burned.
不过要记住，当你吃辣食的时候，大脑会认为你被灼烫了。