为什么英国人如此钟爱茶的味道(1)

Tea has become entrenched in the British way of life, from the humble tea break to the afternoon tea to be enjoyed – in a jacket and tie, of course, gentlemen – at the very swankiest of London hotels.

从简易的普通茶歇，到伦敦顶级奢华酒店供应的下午茶，饮茶俨然已成为英伦生活方式中不可或缺的一部分。而为了享用茶餐，绅士们甚至还要穿着西装、打上领带。

But what are the molecules behind the taste of this beloved beverage? And does how you take your tea say something about who you are?

而身为饮品界的英伦宠儿，茶香的根源到底是什么呢？我们又能否从一个人喝茶的方式中，多少窥探出些许关于其真实境况的信息呢？

To answer that, it’s worth first trying to work out what it is exactly that makes tea taste the way it does. Tea’s flavour is intimately affected by how it is grown, processed, and brewed – beginning with the light. Tea bushes – Latin name camellia sinesis – are grown in terraces all over the tropics and subtropics. But if the intent is to make certain kinds of green tea from them, like matcha, growers will make sure they are carefully shaded with nets or mats. Less sun causes them to produce more chlorophyll as well as fewer polyphenols, a class of molecules that imparts tea’s singular astringency.

想要解答这些问题，首先，我们有必要设法搞清楚：究竟是什么赋予了茶以独特的味道。茶叶的味道深受其栽培方式、加工方式以及冲泡方式的影响。而所有这些都得从阳光说起。在全球热带和亚热带的梯田中，人工种植的茶树（拉丁名为“camellia sinesis”）随处可见。然而，倘若种植者意在将它们制作成某种特定类型的绿茶（比如抹茶），他们便会小心翼翼地用网眼织物或者席子遮住茶树，确保它们不会过度曝光。这是因为太阳光照越少，茶叶生成的叶绿素就会越多，同时多酚类物质就会越少，而茶本身那种奇异的涩味便是源自于后面一类分子。

Of course, some of us may like that taste, and tea processing can amp it up. After the new leaves and buds have been plucked from a bush, they are laid out to dry. How long they lie again depends on the kind of tea intended. For green teas, the leaves are almost immediately tossed in a hot pan or steamed (tea might look like the rawest of edibles, but it is actually cooked, or at least heat-treated). An oolong results when the leaves are dried a little, bruised and only then cooked. And a black tea – the most popular variant, accounting for 78% of the tea drunk world-wide – results when the bruised leaves dry quite a long while before being finished in the pan.

当然，我们之中可能有些人会喜欢那种味道，而且制茶工艺还可以加重这种味道。茶农先将新叶和嫩芽从一株株茶树上采摘下来，然后把它们摊开来放置，以便晾干，而摊放时间的长短则取决于要制作的茶的类型。如要制成绿茶，茶农几乎需在第一时间就把鲜叶扔进热锅里加热杀青，也有的绿茶是蒸气杀青（尽管乍一看上去，茶可能像最原始而未经加工的食品，但实际上，茶是烹熟的，或者起码也经过了热处理）。如要制成乌龙茶，茶农需要在叶子稍干一些后，将其捣碎、揉捻，在这之后再烘焙烹熟便可大功告成。而如果要制成红茶，茶农需先把叶子捣碎、揉捻，再将它晾相当长的一段时间，然后在锅中完成最后的烘炒。红茶是最为流行的茶品种，占到全世界茶饮消费总量的78%。

What’s behind all this is that as the tea leaves are drying, enzymes native to the tea plant are busily transforming simple molecules into more complex ones. The longer the tea spends drying, the longer those enzymes have to work – and the more these molecules build up in the tea leaves. The most famous in tea-chemistry circles is probably theaflavin, a tangle of carbon rings responsible for some of the ruddy colour of black teas as well as some of the astringency.

蕴藏在这一切背后的化学原理，就是茶树原生的各种酶素在茶叶逐渐晾干的过程中，马不停蹄地将结构简单的分子转化成结构复杂的分子。茶叶晾干的时间越长，这些酶素发挥效用的时间就越长，进而这些在茶叶中组合聚集起来的分子也就越多。在茶叶化学界最负盛名的恐怕要数茶黄素了，这是一团纠结在一起的碳环，因了它的存在，红茶多了几分红润的色泽，还多了些许涩味。

Firing the tea leaves calls the process to a halt by destroying the enzymes. As a result, there’s very little theaflavin and related molecules in, say, green teas. But aside from polyphenols, hundreds of other compounds build up in the tea over time; their roles in crafting tea’s bouquet and taste are not yet clear. Regardless, the end result is a different chemical profile for each kind of tea.

茶叶的烘烤焙制工艺开始后，这一反应过程因酶素被摧毁而被迫终止。因此，在诸如绿茶等一些茶制成品中，茶黄素及其相关分子的含量微乎其微。不过，随着时间的推移，除了多酚类物质，茶叶中还组合聚集了数百种其它种类的化合物；而在茶的香味和口感的缔造过程中，它们发挥了怎样的作用，如今尚无定论。无论如何，最终的结果便是，每种茶都有了不同的化学剖面。

Given how much tea people drink, there's growing interest in understanding whether this habit has any medical benefits. It appears that molecules found in tea can protect cells in a dish from some kinds of damage, but despite copious research,there is conflicting evidence on whether tea-drinking provides benefits beyond warm hands and an alert mind.

鉴于人们的饮茶量如此之大，学界对于饮茶习惯是否具有医学效用这一问题的研究兴趣日益高涨。尽管有大量研究表明，在茶叶中发现的分子似乎可以在培养皿中保护细胞，使其免受某些类型的损伤，但在饮茶是否能为人们带来暖手和提神之外的其它益处的这个问题上，各种证据之间又充满了矛盾。

Because, of course, there are the stimulants. Brewed tea has roughly half the caffeine of an equivalent volume of coffee, but it is still plenty for a mid-afternoon pick-me-up. You might have heard that caffeine in tea gives a different high from the caffeine in coffee. Many studies have found that if this is the case, it’s because of an amino acid called theanine, which occurs in tea. When volunteers consume both caffeine and theanine – versus caffeine and other tea molecules – they show moderately more alertness and better ability to switch between tasks than with caffeine alone. The amount in a given cuppa may not be the same as the doses given during a study, however, and the effect of theanine is not enormous. But all on its own, the caffeine will give you a nice lift.

这是因为茶的确对大脑神经有刺激性。虽然与同等剂量的咖啡相比，煮好的茶所含的咖啡因大约只有前者的一半，但依然足够起到午后提神的作用。你或许已有耳闻，茶中的咖啡因所带给人的兴奋感与咖啡所含的咖啡因有所不同。许多研究已经表明，如果事实的确如此，那么差异的出现源自于茶叶中存在的一种氨基酸，它名为“茶氨酸”。当志愿者同时摄入咖啡因与茶氨酸时，相较于同时摄入咖啡因与其它的茶分子（单靠咖啡因醒神），他们表现出略微强一些的敏捷性和更好的多任务切换能力。不过，一杯茶水中所含的茶氨酸和研究中所用的剂量可能会有差异，而且茶氨酸的效用也并不是很大。但是，就咖啡因自身而言，茶的提神效果还是挺不错的。