【英语时差8,16】蜂蜜：可作食品酵母和天然防腐剂

 Leave it on the shelf too long and honey begins to crystallize.   Heating the honey returns it to its original condition, but if you add water, you could ruin the honey completely. That's because honey, which is a preservative¹ in its original state, ferments³ once it's diluted⁴.

In ancient times, honey was used as a food preservative. It works as a preservative because the high concentration of sugar in honey forces the water out of any yeast⁵ or bacteria cells that could otherwise contaminate the food. This process, known as "osmosis," is also what makes salt such an effective preservative. Eventually, the process of osmosis destroys those cells by drawing out all their water--in other words, by drying them up.

So because of its high sugar concentration, pure honey will never ferment² or go bad. It may crystallize but by soaking the jar in hot water you can turn it back into a liquid. Adding water, however, lowers the concentration of sugar in the honey and turns a natural preservative into an excellent food for yeast and bacteria.

You may not want a fermented⁶ jar of honey on your shelf, but ancient people turned that characteristic of honey to their advantage in creating what may well have been the very first alcoholic⁷ beverage⁸. Honey mixed in water and allowed to ferment, produces the drink called "mead⁹."So you may or may not want to add water to your honey. If what you want is mead, go ahead, but if you want your honey to last, . . . keep it pure.

Next time on "A Moment of Science," we'll see why honey can help baked goods last longer.  

1 preservative   

n.防腐剂；防腐料；保护料；预防药

参考例句：

• New timber should be treated with a preservative.新采的圆木应进行防腐处理。
• Salt is a common food preservative.盐是一种常用的食物防腐剂。

2 ferment   

vt.使发酵；n./vt.（使）激动，（使）动乱

参考例句：

• Fruit juices ferment if they are kept a long time.果汁若是放置很久，就会发酵。
• The sixties were a time of theological ferment.六十年代是神学上骚动的时代。

3 ferments   

n.酵素( ferment的名词复数 )；激动；骚动；动荡v.（使）发酵( ferment的第三人称单数 )；（使）激动；骚动；骚扰

参考例句：

• These chemically active ferments cause havoc. 这些化学活性的酶造成广泛损害。 来自辞典例句
• High solid ferments and yeast lees contract to highlight textural qualities. 采用固体发和酵母分离技术提高酒的品质。 来自互联网

4 diluted   

无力的，冲淡的

参考例句：

• The paint can be diluted with water to make a lighter shade. 这颜料可用水稀释以使色度淡一些。
• This pesticide is diluted with water and applied directly to the fields. 这种杀虫剂用水稀释后直接施用在田里。

5 yeast   

n.酵母；酵母片；泡沫；v.发酵；起泡沫

参考例句：

• Yeast can be used in making beer and bread.酵母可用于酿啤酒和发面包。
• The yeast began to work.酵母开始发酵。

6 fermented   

v.（使）发酵( ferment的过去式和过去分词 )；（使）激动；骚动；骚扰

参考例句：

• When wine is fermented, it gives off gas. 酒发酵时发出气泡。 来自《简明英汉词典》
• His speeches fermented trouble among the workers. 他的演讲在工人中引起骚动。 来自辞典例句

7 alcoholic   

adj.（含）酒精的，由酒精引起的；n.酗酒者

参考例句：

• The alcoholic strength of brandy far exceeds that of wine.白兰地的酒精浓度远远超过葡萄酒。
• Alcoholic drinks act as a poison to a child.酒精饮料对小孩犹如毒药。

8 beverage   

n.(水，酒等之外的)饮料

参考例句：

• The beverage is often colored with caramel.这种饮料常用焦糖染色。
• Beer is a beverage of the remotest time.啤酒是一种最古老的饮料。

9 mead   

n.蜂蜜酒

参考例句：

• He gave me a cup of mead.他给我倒了杯蜂蜜酒。
• He drank some mead at supper.晚饭时他喝了一些蜂蜜酒。