What the sommelier should know: the fermentation process
To start off let's jump back a few centuries, since only from the 17th century on, when the effects of yeast became known, different brewing methods could evolve. Before that time the success of the fermentation process was more or less a matter of pure luck, often regarded as depending on the favour of the gods.
It was the French chemist and microbiologist Louis Pasteur who first found out that tiny organisms (yeast fungus) had the most important share in the fermentation process. Tody many different types of yeast suitable for brewing beer are known.