I don't intend to comment on the origins of alcohol. This writeup merely points at one of the many facets of alcohol that we may take for granted.
Alcohol was being consumed unwittingly by our ancestors long before the cereals we know of were used to make bread. A weak, unfiltered, variant of the beer we know and love today was the first use of Barley known to man. The beer was made to be stored during months of drought, since plain water could not be stored for a long period of time before becoming stagnant and very harmful due to the high bacterial content. The small amounts of alcohol contained in that early beer was enough to keep the bacterial content to an acceptable limit.
The same may be said about wine. One may wonder why Christian religions claim that Jesus left us bread and wine as a symbol of Himself when bread and water might seem more appropriate. Again, the warm weather in Israel made stored water 2000 years ago a certain death. Wine, on the other hand, contained sufficient alcohol to keep the stored liquid close enough to sterility.
So the question arises. Should we thank alcohol for our existence today? The answer in my humble opinion is a definite yes. Survival of the race has always depended on sufficient amounts of safe water during times of drought and alcohol made this possible in Western civilisations.
The reason for which I specify western civilisations is that Eastern Civilisations seemed to emphasise the use of tea far before it was transported to the West. Tea was believed to have miraculous, life-extending properties, but in view of what is said about alcohol, the probability is that boiling served the same purpose, killing off harmful pathogens before the water was consumed.