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Chemical reactions: foundations Reading and listening
When the miracle became science The earliest evidence of the production and consumption of wine is found in a ceramic vase found in the Zagros mountains (in what is now Iran and Iraq) which is dated around 5400 BCE. Traditionally wine, and even more so its production process, has been related to the mysterious and divine. In fact, both the Greeks and later the Romans had a god of wine and vineyards: Dionysus and Bacchus, respectively. These beliefs changed, developed and eventually disappeared with the help of logic and curiosity. This meant that in the Middle Ages it was thought that wine resulted from the decomposition of matter (grape juice), while in the 19th Century it was discovered that wine was the result of a chemical reaction: fermentation. The French chemist Louis Pasteur was the first person to explain fermentation, and thereby provided a scientific basis for the production of wine. This chemical change involves the transformation of sugar (glucose) into ethyl alcohol and carbon dioxide, which occurs due to the activity of yeasts (fungi) such as Candida, Pichia, Zygosaccharomyces or the popular Saccharomyces cerevisiae. There is now a science that specialises in the study of these chemical process. Do you know what it’s called?
1 Who was the Greek god of wine? 2 What chemical reaction is responsible for the production of wine? 3 When was fermentation discovered? 4 What turns into what in the fermentation process? 5 What are the main organisms responsible for fermentation?
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