You’ve just opened a bottle of wine for dinner. On the label, you see these words: Contains Sulfites. What are sulfites? And what are they doing in your wine?

　　Chemical Compounds

　　Sulfites are chemical compounds found naturally in grapes, garlic and other plants. Thousands of years ago, people realized something nifty about sulfites: they kill or slow the growth of bacteria and most yeasts. This comes in handy for winemakers, who add specific yeasts to ferment wine, and don’t want wild yeasts or bacteria to spoil it. Sulfites prevent spoilage in wine, acting as a preservative.

　　The amount of sulfites naturally in grapes is very small, and there’s a bit more produced during fermentation. But to take full advantage of sulfites’ preservative abilities, winemakers add a little more to the process. The Egyptians sterilized wine containers with sulfites, and sulfites have been added to wine for hundreds of years.

　　Wine And Sulfites

　　So the relationship between wine and sulfites goes way back. But in 1985, the Food and Drug Administration required wine with added sulfites to say so on the label. Why?

　　Researchers had recently discovered that less than one percent of the population is sensitive to sulfites. Most have mild reactions, like an itchy rash. But some folks have life-threatening reactions, including difficulty breathing and low blood pressure.

　　These rare but serious reactions are most often seen in asthmatics. Not all asthmatics are sensitive to sulfites, but the label’s there for those who need to steer clear. As the old saying goes, in wine–and now on the label–there is truth!

　　亚硫酸盐是什么？

　　设想一下，你在晚餐时刚刚打开了一瓶酒，你会在酒瓶的标签上看到：含亚硫酸盐。亚硫酸盐是什么？这些成分在你的酒中发挥什么样的作用呢？

　　化合物

　　亚硫酸盐是在葡萄，大蒜和其他植物中常见的一种化合物。几千年前，人们就发现了亚硫酸盐的一些妙用：它们能杀死细菌，或者降低细菌滋生和发酵的速度。这个发现对于酿酒师来说是非常重要的，他们通常会在酒中加一些特定的酵母使酒发酵，但是同时，他们又不想野生酵母和细菌破坏了这个过程。而亚硫酸盐就能阻止酒的腐坏，在其中发挥了防腐剂的作用。

　　葡萄中含有亚硫酸盐的量非常少，在发酵过程中数量会有稍许的增加。但是，为了有效利用亚硫酸盐的防腐作用，酿酒师们通常会在酿酒过程中多添加一点点亚硫酸盐。埃及人也曾使用亚硫酸盐对酒类容器进行杀菌，而且，亚硫酸盐被添加进入酒类也已经有了几百年历史了。

　　酒和亚硫酸盐

　　因此，酒和亚硫酸盐的关系其实可以回溯到很久很久以前。但在1985年，食品与药品管理局要求，若酒类有添加亚硫酸盐，需要在标签上注明，为什么？

　　因为有研究人员之前发现，有不到1%的人会对亚硫酸盐产生过敏反应，虽然多数人的反应比较轻微，比如说会起很痒的皮疹，但有部分人的过敏反应会威胁到生命安全，这些反应包括呼吸困难或低血压等。

　　我们经常会在哮喘症患者身上看到这些少有但严重的反应。其实，也并不是所有的哮喘症患者都会对亚硫酸盐过敏，标签上的说明只是为了警示需要注意的人避开这些成分。就像老话常说的那样，酒后，现在是标注在标签上-吐真言！