A piece of chocolate, honey on bread, in tea or fruit juice is something everyone of us indulges in once in a while. All these foods have one thing in common - a sweet taste caused by the sugars they contain. Sugar is a basic ingredient that we know and use every day. It is found in various parts of plants, but is only obtained industrially from sugar beet and sugar cane. When we take some sugar in our mouth, our body quickly converts it into the energy that our body cells need to function.

However, sugar can be used for purposes other than sweetening tea. With a little help from microorganisms called yeast, we can turn sugar into alcohol. Yeasts are microscopic organisms that live around us - in the air, on fruit or in dough. When yeast comes into contact with sugar, it starts working. If there is no oxygen in the surrounding environment, they process the sugar to form carbon dioxide and alcohol - ethanol.

Imagine you have a glass of fruit juice. If you add yeast to it, and ideally put a fermentation stopper (that is, one that allows carbon dioxide to escape from the glass but prevents oxygen from getting in), you will find after a while that the juice is not as sweet and tastes different - it contains alcohol. In the food industry, fermentation of sugars produces most types of alcohol, from beer, wine, cider to mead and more.

This transformation of two seemingly completely different raw materials is an example of a natural change that, although not visible to the eye, gives rise to something that has played an important role in human culture and tradition for thousands of years.